[V0 Deprecation] Remove V0 core (#25321)

Signed-off-by: Woosuk Kwon <woosuk@thinkingmachines.ai>
Signed-off-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>

.buildkite/test-pipeline.yaml

@@ -148,7 +148,6 @@ steps:
   num_gpus: 4
   source_file_dependencies:
   - vllm/distributed/
-  - vllm/core/
   - tests/distributed/test_utils
   - tests/distributed/test_pynccl
   - tests/distributed/test_events
@@ -867,8 +866,6 @@ steps:
   - tests/distributed/
   - vllm/compilation
   - vllm/worker/worker_base.py
-  - vllm/worker/worker.py
-  - vllm/worker/model_runner.py
   - entrypoints/llm/test_collective_rpc.py
   - tests/v1/test_async_llm_dp.py
   - tests/v1/test_external_lb_dp.py

.github/CODEOWNERS

@@ -4,10 +4,8 @@
 # This lists cover the "core" components of vLLM that require careful review
 /vllm/attention @LucasWilkinson
 /vllm/attention/backends/abstract.py @WoosukKwon @zhuohan123 @youkaichao @alexm-redhat @comaniac @njhill
-/vllm/core @zhuohan123 @youkaichao @alexm-redhat @comaniac @njhill
 /vllm/executor/executor_base.py @zhuohan123 @youkaichao @alexm-redhat @comaniac @njhill @22quinn
 /vllm/worker/worker_base.py @zhuohan123 @youkaichao @alexm-redhat @comaniac @njhill @22quinn
-/vllm/worker/worker.py @zhuohan123 @youkaichao @alexm-redhat @comaniac @njhill
 /vllm/model_executor/layers/fused_moe @mgoin
 /vllm/model_executor/layers/sampler.py @zhuohan123 @youkaichao @alexm-redhat @comaniac @njhill @NickLucche
 /vllm/model_executor/layers/quantization @mgoin @robertgshaw2-redhat @tlrmchlsmth @yewentao256

pyproject.toml

@@ -70,7 +70,6 @@ line-length = 80
 "vllm/_version.py" = ["ALL"]
 # Python 3.8 typing - skip V0 code
 "vllm/attention/**/*.py" = ["UP006", "UP035"]
-"vllm/core/**/*.py" = ["UP006", "UP035"]
 "vllm/engine/**/*.py" = ["UP006", "UP035"]
 "vllm/executor/**/*.py" = ["UP006", "UP035"]
 "vllm/worker/**/*.py" = ["UP006", "UP035"]
@@ -117,7 +116,6 @@ files = [
     "vllm/*.py",
     "vllm/assets",
     "vllm/entrypoints",
-    "vllm/core",
     "vllm/inputs",
     "vllm/logging_utils",
     "vllm/multimodal",

vllm/attention/backends/differential_flash_attn.py

@@ -4,7 +4,7 @@
 from collections import defaultdict
 from dataclasses import dataclass
 from itertools import accumulate
-from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple, Type
+from typing import Any, Dict, List, Optional, Tuple, Type
 
 import torch
 from einops import rearrange
@@ -34,9 +34,6 @@ from vllm.utils import async_tensor_h2d, make_tensor_with_pad
 from vllm.vllm_flash_attn import (flash_attn_varlen_func,
                                   flash_attn_with_kvcache)
 
-if TYPE_CHECKING:
-    from vllm.worker.model_runner import ModelInputForGPUBuilder
-
 logger = init_logger(__name__)
 
 
@@ -329,7 +326,7 @@ class DifferentialFlashAttentionMetadata(AttentionMetadata):
 class DifferentialFlashAttentionMetadataBuilder(
         AttentionMetadataBuilder[DifferentialFlashAttentionMetadata]):
 
-    def __init__(self, input_builder: "ModelInputForGPUBuilder"):
+    def __init__(self, input_builder):
         self.input_builder = input_builder
         self.runner = input_builder.runner
         self.sliding_window = input_builder.sliding_window
@@ -350,9 +347,8 @@ class DifferentialFlashAttentionMetadataBuilder(
         self.num_decode_tokens = 0
         self.has_prefix_cache_hit = False
 
-    def _add_seq_group(
-            self, inter_data: "ModelInputForGPUBuilder.InterDataForSeqGroup",
-            chunked_prefill_enabled: bool, prefix_cache_hit: bool):
+    def _add_seq_group(self, inter_data, chunked_prefill_enabled: bool,
+                       prefix_cache_hit: bool):
         """Add a sequence group to the metadata. Specifically update/append
         1. context length.
         2. block table.

vllm/attention/backends/dual_chunk_flash_attn.py

@@ -4,7 +4,7 @@
 """
 import math
 from dataclasses import dataclass
-from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple, Type
+from typing import Any, Dict, List, Optional, Tuple, Type
 
 import torch
 import torch.distributed
@@ -22,9 +22,6 @@ from vllm.utils import async_tensor_h2d
 from vllm.vllm_flash_attn import (flash_attn_varlen_func,
                                   flash_attn_with_kvcache, sparse_attn_func)
 
-if TYPE_CHECKING:
-    from vllm.worker.model_runner import ModelInputForGPUBuilder
-
 logger = init_logger(__name__)
 
 
@@ -224,9 +221,8 @@ class DualChunkFlashAttentionMetadataBuilder(FlashAttentionMetadataBuilder):
         super().prepare()
         self.orig_seq_lens: List[int] = []
 
-    def _add_seq_group(
-            self, inter_data: "ModelInputForGPUBuilder.InterDataForSeqGroup",
-            chunked_prefill_enabled: bool, prefix_cache_hit: bool):
+    def _add_seq_group(self, inter_data, chunked_prefill_enabled: bool,
+                       prefix_cache_hit: bool):
         super()._add_seq_group(inter_data, chunked_prefill_enabled,
                                prefix_cache_hit)
         for prompt_len, seq_len in zip(inter_data.prompt_lens,

vllm/attention/backends/flash_attn.py

@@ -4,7 +4,7 @@
 from collections import defaultdict
 from dataclasses import dataclass
 from itertools import accumulate
-from typing import TYPE_CHECKING, Dict, List, Optional, Tuple, Type
+from typing import Dict, List, Optional, Tuple, Type
 
 import torch
 
@@ -31,9 +31,6 @@ from vllm.utils import async_tensor_h2d, make_tensor_with_pad
 from vllm.vllm_flash_attn import (flash_attn_varlen_func,
                                   flash_attn_with_kvcache)
 
-if TYPE_CHECKING:
-    from vllm.worker.model_runner import ModelInputForGPUBuilder
-
 logger = init_logger(__name__)
 
 
@@ -312,7 +309,7 @@ class FlashAttentionMetadata(AttentionMetadata):
 class FlashAttentionMetadataBuilder(
         AttentionMetadataBuilder[FlashAttentionMetadata]):
 
-    def __init__(self, input_builder: "ModelInputForGPUBuilder"):
+    def __init__(self, input_builder):
         self.input_builder = input_builder
         self.runner = input_builder.runner
         self.sliding_window = input_builder.sliding_window
@@ -332,9 +329,8 @@ class FlashAttentionMetadataBuilder(
         self.num_decode_tokens = 0
         self.has_prefix_cache_hit = False
 
-    def _add_seq_group(
-            self, inter_data: "ModelInputForGPUBuilder.InterDataForSeqGroup",
-            chunked_prefill_enabled: bool, prefix_cache_hit: bool):
+    def _add_seq_group(self, inter_data, chunked_prefill_enabled: bool,
+                       prefix_cache_hit: bool):
         """Add a sequence group to the metadata. Specifically update/append
         1. context length.
         2. block table.

vllm/attention/backends/mla/common.py

@@ -193,8 +193,7 @@ from collections import defaultdict
 from contextlib import contextmanager
 from dataclasses import dataclass
 from itertools import accumulate
-from typing import (TYPE_CHECKING, Any, Dict, Generic, List, Optional, Tuple,
-                    Type, TypeVar)
+from typing import Any, Dict, Generic, List, Optional, Tuple, Type, TypeVar
 
 import torch
 
@@ -233,9 +232,6 @@ except ImportError:
     except ImportError:
         flash_attn_varlen_func = None
 
-if TYPE_CHECKING:
-    from vllm.worker.model_runner import ModelInputForGPUBuilder
-
 is_hip = current_platform.is_rocm()
 
 
@@ -638,7 +634,7 @@ class MLACommonMetadataBuilder(AttentionMetadataBuilder[T], Generic[T]):
     """
     BLOCK_TABLE_EXTENDER: list[list[int]] = []
 
-    def __init__(self, input_builder: "ModelInputForGPUBuilder"):
+    def __init__(self, input_builder):
         self.input_builder = input_builder
         self.runner = input_builder.runner
         self.sliding_window = input_builder.sliding_window
@@ -668,9 +664,8 @@ class MLACommonMetadataBuilder(AttentionMetadataBuilder[T], Generic[T]):
         self.num_decode_tokens = 0
         self.has_prefix_cache_hit = False
 
-    def _add_seq_group(
-            self, inter_data: "ModelInputForGPUBuilder.InterDataForSeqGroup",
-            chunked_prefill_enabled: bool, prefix_cache_hit: bool):
+    def _add_seq_group(self, inter_data, chunked_prefill_enabled: bool,
+                       prefix_cache_hit: bool):
         """Add a sequence group to the metadata. Specifically update/append
         1. context length.
         2. block table.

vllm/attention/backends/placeholder_attn.py

@@ -4,7 +4,7 @@
 from collections import defaultdict
 from dataclasses import dataclass
 from itertools import accumulate
-from typing import TYPE_CHECKING, Dict, List, Optional, Tuple, Type
+from typing import Dict, List, Optional, Tuple, Type
 
 import torch
 
@@ -13,9 +13,6 @@ from vllm.attention.backends.abstract import (AttentionBackend, AttentionImpl,
                                               AttentionMetadataBuilder)
 from vllm.attention.backends.utils import CommonAttentionState
 from vllm.multimodal import MultiModalPlaceholderMap
-
-if TYPE_CHECKING:
-    from vllm.worker.model_runner import (ModelInputForGPUBuilder)
 from vllm.utils import async_tensor_h2d
 
 # Placeholder attention backend for models like Mamba and pooling models that
@@ -204,7 +201,7 @@ class PlaceholderAttentionMetadata(AttentionMetadata):
 class PlaceholderAttentionMetadataBuilder(
         AttentionMetadataBuilder[PlaceholderAttentionMetadata]):
 
-    def __init__(self, input_builder: "ModelInputForGPUBuilder"):
+    def __init__(self, input_builder):
 
         self.input_builder = input_builder
         self.runner = input_builder.runner
@@ -220,9 +217,7 @@ class PlaceholderAttentionMetadataBuilder(
         self.num_prefill_tokens = 0
         self.num_decode_tokens = 0
 
-    def _add_seq_group(
-            self, inter_data: "ModelInputForGPUBuilder.InterDataForSeqGroup",
-            chunked_prefill_enabled: bool):
+    def _add_seq_group(self, inter_data, chunked_prefill_enabled: bool):
         """Add a sequence group to the metadata. Specifically update/append
         1. context length.
         """

vllm/attention/backends/rocm_aiter_mla.py

@@ -3,7 +3,7 @@
 
 from contextlib import contextmanager
 from dataclasses import dataclass
-from typing import TYPE_CHECKING, Optional, Type, Union
+from typing import Optional, Type, Union
 
 import torch
 
@@ -19,9 +19,6 @@ from vllm.attention.backends.utils import (compute_slot_mapping,
 from vllm.attention.ops.rocm_aiter_mla import (aiter_mla_decode_fwd,
                                                get_aiter_mla_metadata)
 
-if TYPE_CHECKING:
-    from vllm.worker.model_runner import ModelInputForGPUBuilder
-
 
 def is_aiter_mla_enabled() -> bool:
     return envs.VLLM_ROCM_USE_AITER \
@@ -110,7 +107,7 @@ class AiterMLAMetadata(MLACommonMetadata):
 class AiterMLAMetadataBuilder(MLACommonMetadataBuilder[AiterMLAMetadata]):
     BLOCK_TABLE_EXTENDER: list[list[int]] = [[]]
 
-    def __init__(self, input_builder: "ModelInputForGPUBuilder"):
+    def __init__(self, input_builder):
         super().__init__(input_builder)
         assert self.block_size == 1, "AITER MLA requires only block size 1."
 

vllm/attention/backends/utils.py

@@ -35,9 +35,6 @@ PAD_SLOT_ID = -1
 # if we have at least this many elements. Could be tuned further.
 _COMPUTE_SLOT_MAPPING_NUMPY_NUMEL = 256
 
-if TYPE_CHECKING:
-    from vllm.worker.model_runner import ModelInputForGPUBuilder
-
 
 def is_block_tables_empty(block_tables: Union[None, Dict]):
     """
@@ -129,7 +126,7 @@ class CommonMetadataBuilder(AttentionMetadataBuilder[TAttentionMetadata]):
 
     _metadata_cls: Type[TAttentionMetadata]
 
-    def __init__(self, input_builder: "ModelInputForGPUBuilder"):
+    def __init__(self, input_builder):
         self.input_builder = input_builder
         self.runner = input_builder.runner
 
@@ -149,9 +146,7 @@ class CommonMetadataBuilder(AttentionMetadataBuilder[TAttentionMetadata]):
         self.num_prefill_tokens = 0
         self.num_decode_tokens = 0
 
-    def _add_seq_group(
-            self, inter_data: "ModelInputForGPUBuilder.InterDataForSeqGroup",
-            chunked_prefill_enabled: bool):
+    def _add_seq_group(self, inter_data, chunked_prefill_enabled: bool):
         is_prompt = inter_data.is_prompt
         block_tables = inter_data.block_tables
 

vllm/core/block/block_table.py

-# SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-
-import math
-from typing import List, Optional
-
-from vllm.core.block.common import BlockList
-from vllm.core.block.interfaces import Block, DeviceAwareBlockAllocator
-from vllm.utils import Device, cdiv, chunk_list
-
-
-class BlockTable:
-    """A class to manage blocks for a specific sequence.
-
-    The BlockTable maps a sequence of tokens to a list of blocks, where each
-    block represents a contiguous memory allocation for a portion of the 
-    sequence. The blocks are managed by a DeviceAwareBlockAllocator, which is
-    responsible for allocating and freeing memory for the blocks.
-
-    Args:
-        block_size (int): The maximum number of tokens that can be stored in a
-            single block.
-        block_allocator (DeviceAwareBlockAllocator): The block allocator used to
-            manage memory for the blocks.
-        _blocks (Optional[List[Block]], optional): An optional list of existing
-            blocks to initialize the BlockTable with. If not provided, an empty
-            BlockTable is created.
-        max_block_sliding_window (Optional[int], optional): The number of
-            blocks to keep around for each sequence. If None, all blocks
-            are kept (eg., when sliding window is not used).
-            It should at least fit the sliding window size of the model.
-
-    Attributes:
-        _block_size (int): The maximum number of tokens that can be stored in a
-            single block.
-        _allocator (DeviceAwareBlockAllocator): The block allocator used to
-            manage memory for the blocks.
-        _blocks (Optional[List[Block]]): The list of blocks managed by this
-            BlockTable.
-        _num_full_slots (int): The number of tokens currently stored in the
-            blocks.
-    """
-
-    def __init__(
-        self,
-        block_size: int,
-        block_allocator: DeviceAwareBlockAllocator,
-        _blocks: Optional[List[Block]] = None,
-        max_block_sliding_window: Optional[int] = None,
-    ):
-        self._block_size = block_size
-        self._allocator = block_allocator
-        if _blocks is None:
-            _blocks = []
-        self._blocks: BlockList = BlockList(_blocks)
-
-        self._max_block_sliding_window = max_block_sliding_window
-        self._num_full_slots = self._get_num_token_ids()
-
-    @staticmethod
-    def get_num_required_blocks(token_ids: List[int],
-                                block_size: int,
-                                num_lookahead_slots: int = 0) -> int:
-        """Calculates the minimum number of blocks required to store a given
-        sequence of token IDs along with any look-ahead slots that may be
-        required (like in multi-step + chunked-prefill).
-
-        This assumes worst-case scenario, where every block requires a new
-        allocation (e.g. ignoring prefix caching).
-
-        Args:
-            token_ids (List[int]): The sequence of token IDs to be stored.
-            block_size (int): The maximum number of tokens that can be stored in
-                a single block.
-            num_lookahead_slots (int): look-ahead slots that the sequence may
-                require.
-
-        Returns:
-            int: The minimum number of blocks required to store the given
-                sequence of token IDs along with any required look-ahead slots.
-        """
-        return cdiv(len(token_ids) + num_lookahead_slots, block_size)
-
-    def allocate(self,
-                 token_ids: List[int],
-                 device: Device = Device.GPU,
-                 extra_hash: Optional[int] = None) -> None:
-        """Allocates memory blocks for storing the given sequence of token IDs.
-
-        This method allocates the required number of blocks to store the given
-        sequence of token IDs.
-
-        Args:
-            token_ids (List[int]): The sequence of token IDs to be stored.
-            device (Device, optional): The device on which the blocks should be
-                allocated. Defaults to Device.GPU.
-            extra_hash (Optional[int]): The hash value of additional
-                factors, such as adapters, that influence the block hash
-                in the prefixcaching block.
-        """
-        assert not self._is_allocated
-        assert token_ids
-        blocks = self._allocate_blocks_for_token_ids(prev_block=None,
-                                                     token_ids=token_ids,
-                                                     device=device,
-                                                     extra_hash=extra_hash)
-        self.update(blocks)
-        self._num_full_slots = len(token_ids)
-
-    def update(self, blocks: List[Block]) -> None:
-        """Resets the table to the newly provided blocks 
-        (with their corresponding block ids)
-        """
-        self._blocks.update(blocks)
-
-    def append_token_ids(self,
-                         token_ids: List[int],
-                         num_lookahead_slots: int = 0,
-                         num_computed_slots: Optional[int] = None,
-                         extra_hash: Optional[int] = None) -> None:
-        """Appends a sequence of token IDs to the existing blocks in the
-        BlockTable.
-
-        This method appends the given sequence of token IDs to the existing
-        blocks in the BlockTable. If there is not enough space in the existing
-        blocks, new blocks are allocated using the `ensure_num_empty_slots`
-        method to accommodate the additional tokens.
-
-        The token IDs are divided into chunks of size `block_size` (except for
-        the first chunk, which may be smaller), and each chunk is appended to a
-        separate block.
-
-        Args:
-            token_ids (List[int]): The sequence of token IDs to be appended.
-            num_computed_slots (Optional[int]): The number of KV cache slots
-                that are already filled (computed).
-                When sliding window is enabled, this is used to compute how many
-                blocks to drop at the front of the sequence.
-                Without sliding window, None can be passed.
-                Without chunked prefill, it should be the same as
-                _num_full_slots.
-            extra_hash (Optional[int]): The hash value of additional
-                factors such as adapters that influence the block, apart
-                from the token_ids.
-        """
-        assert self._is_allocated, "no blocks have been allocated"
-        assert len(self._blocks) > 0
-
-        # Drop blocks that are no longer needed due to sliding window
-        if self._max_block_sliding_window is not None:
-            null_block = self._allocator.allocate_or_get_null_block()
-            assert num_computed_slots is not None
-            end_block_idx = (num_computed_slots //
-                             self._block_size) - self._max_block_sliding_window
-            for idx in range(0, end_block_idx):
-                b = self._blocks[idx]
-                if b is not null_block:
-                    self._allocator.free(b)
-                    self._blocks[idx] = null_block
-
-        # Ensure there are enough empty slots for the new tokens plus
-        # lookahead slots
-        self.ensure_num_empty_slots(num_empty_slots=len(token_ids) +
-                                    num_lookahead_slots,
-                                    extra_hash=extra_hash)
-
-        # Update the blocks with the new tokens
-        first_block_idx = self._num_full_slots // self._block_size
-        token_blocks = self._chunk_token_blocks_for_append(token_ids)
-
-        for i, token_block in enumerate(token_blocks):
-            self._blocks.append_token_ids(first_block_idx + i, token_block)
-
-        self._num_full_slots += len(token_ids)
-
-    def ensure_num_empty_slots(self,
-                               num_empty_slots: int,
-                               extra_hash: Optional[int] = None) -> None:
-        """Ensures that the BlockTable has at least the specified number of
-        empty slots available.
-
-        This method checks if the BlockTable has enough empty slots (i.e.,
-        available space) to accommodate the requested number of tokens. If not,
-        it allocates additional blocks on the GPU to ensure that the required
-        number of empty slots is available.
-
-        Args:
-            num_empty_slots (int): The minimum number of empty slots required.
-            extra_hash (Optional[int]): The hash value of additional
-                factors such as adapters that influence the block, apart
-                from the token_ids.
-        """
-        # Currently the block table only supports
-        # appending tokens to GPU blocks.
-        device = Device.GPU
-        assert self._is_allocated
-
-        if self._num_empty_slots >= num_empty_slots:
-            return
-
-        slots_to_allocate = num_empty_slots - self._num_empty_slots
-        blocks_to_allocate = cdiv(slots_to_allocate, self._block_size)
-
-        for _ in range(blocks_to_allocate):
-            assert len(self._blocks) > 0
-            self._blocks.append(
-                self._allocator.allocate_mutable_block(
-                    prev_block=self._blocks[-1],
-                    device=device,
-                    extra_hash=extra_hash))
-
-    def fork(self) -> "BlockTable":
-        """Creates a new BlockTable instance with a copy of the blocks from the
-        current instance.
-
-        This method creates a new BlockTable instance with the same block size,
-        block allocator, and a copy of the blocks from the current instance. The
-        new BlockTable has its own independent set of blocks, but shares the
-        same underlying memory allocation with the original BlockTable.
-
-        Returns:
-            BlockTable: A new BlockTable instance with a copy of the blocks from
-                the current instance.
-        """
-        assert self._is_allocated
-        assert len(self._blocks) > 0
-        forked_blocks = self._allocator.fork(self._blocks[-1])
-        return BlockTable(
-            block_size=self._block_size,
-            block_allocator=self._allocator,
-            _blocks=forked_blocks,
-            max_block_sliding_window=self._max_block_sliding_window,
-        )
-
-    def free(self) -> None:
-        """Frees the memory occupied by the blocks in the BlockTable.
-
-        This method iterates over all the blocks in the `_blocks` list and calls
-        the `free` method of the `_allocator` object to release the memory
-        occupied by each block. After freeing all the blocks, the `_blocks` list
-        is set to `None`.
-        """
-        for block in self.blocks:
-            self._allocator.free(block)
-        self._blocks.reset()
-
-    @property
-    def physical_block_ids(self) -> List[int]:
-        """Returns a list of physical block indices for the blocks in the
-        BlockTable.
-
-        This property returns a list of integers, where each integer represents
-        the physical block index of a corresponding block in the `_blocks` list.
-        The physical block index is a unique identifier for the memory location
-        occupied by the block.
-
-        Returns:
-            List[int]: A list of physical block indices for the blocks in the
-                BlockTable.
-        """
-        return self._blocks.ids()
-
-    def get_unseen_token_ids(self, sequence_token_ids: List[int]) -> List[int]:
-        """Get the number of "unseen" tokens in the sequence.
-
-        Unseen tokens are tokens in the sequence corresponding to this block
-        table, but are not yet appended to this block table.
-
-        Args:
-            sequence_token_ids (List[int]): The list of token ids in the
-                sequence.
-
-        Returns:
-            List[int]: The postfix of sequence_token_ids that has not yet been
-                appended to the block table.
-        """
-
-        # Since the block table is append-only, the unseen token ids are the
-        # ones after the appended ones.
-        return sequence_token_ids[self.num_full_slots:]
-
-    def _allocate_blocks_for_token_ids(
-            self,
-            prev_block: Optional[Block],
-            token_ids: List[int],
-            device: Device,
-            extra_hash: Optional[int] = None) -> List[Block]:
-        blocks: List[Block] = []
-
-        block_token_ids = []
-        tail_token_ids = []
-        for cur_token_ids in chunk_list(token_ids, self._block_size):
-            if len(cur_token_ids) == self._block_size:
-                block_token_ids.append(cur_token_ids)
-            else:
-                tail_token_ids.append(cur_token_ids)
-
-        if block_token_ids:
-            blocks.extend(
-                self._allocator.allocate_immutable_blocks(
-                    prev_block,
-                    block_token_ids=block_token_ids,
-                    device=device,
-                    extra_hash=extra_hash))
-            prev_block = blocks[-1]
-
-        if tail_token_ids:
-            assert len(tail_token_ids) == 1
-            cur_token_ids = tail_token_ids[0]
-
-            block = self._allocator.allocate_mutable_block(
-                prev_block=prev_block, device=device, extra_hash=extra_hash)
-            block.append_token_ids(cur_token_ids)
-
-            blocks.append(block)
-
-        return blocks
-
-    def _get_all_token_ids(self) -> List[int]:
-        # NOTE: This function is O(seq_len); use sparingly.
-        token_ids: List[int] = []
-
-        if not self._is_allocated:
-            return token_ids
-
-        for block in self.blocks:
-            token_ids.extend(block.token_ids)
-
-        return token_ids
-
-    def _get_num_token_ids(self) -> int:
-        res = 0
-        for block in self.blocks:
-            res += len(block.token_ids)
-
-        return res
-
-    @property
-    def _is_allocated(self) -> bool:
-        return len(self._blocks) > 0
-
-    @property
-    def blocks(self) -> List[Block]:
-        return self._blocks.list()
-
-    @property
-    def _num_empty_slots(self) -> int:
-        assert self._is_allocated
-        return len(self._blocks) * self._block_size - self._num_full_slots
-
-    @property
-    def num_full_slots(self) -> int:
-        """Returns the total number of tokens currently stored in the
-        BlockTable.
-
-        Returns:
-            int: The total number of tokens currently stored in the BlockTable.
-        """
-        return self._num_full_slots
-
-    def get_num_blocks_touched_by_append_slots(
-            self, token_ids: List[int], num_lookahead_slots: int) -> int:
-        """Determine how many blocks will be "touched" by appending the token
-        ids.
-
-        This is required for the scheduler to determine whether a sequence can
-        continue generation, or if it must be preempted.
-        """
-        # Math below is equivalent to:
-        # all_token_ids = token_ids + [-1] * num_lookahead_slots
-        # token_blocks = self._chunk_token_blocks_for_append(all_token_ids)
-        # return len(token_blocks)
-
-        num_token_ids = len(token_ids) + num_lookahead_slots
-        first_chunk_size = self._block_size - (self._num_full_slots %
-                                               self._block_size)
-        num_token_blocks = (1 + math.ceil(
-            (num_token_ids - first_chunk_size) / self._block_size))
-        return num_token_blocks
-
-    def _chunk_token_blocks_for_append(
-            self, token_ids: List[int]) -> List[List[int]]:
-        """Split the token ids into block-sized chunks so they can be easily
-        appended to blocks. The first such "token block" may have less token ids
-        than the block size, since the last allocated block may be partially
-        full.
-
-        If no token ids are provided, then no chunks are returned.
-        """
-
-        if not token_ids:
-            return []
-
-        first_chunk_size = self._block_size - (self._num_full_slots %
-                                               self._block_size)
-        token_blocks = [token_ids[:first_chunk_size]]
-        token_blocks.extend(
-            chunk_list(token_ids[first_chunk_size:], self._block_size))
-        return token_blocks

vllm/core/block/common.py

-# SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-
-from collections import deque
-from dataclasses import dataclass
-from typing import Deque, Dict, Iterable, List, Optional, Protocol, Tuple
-
-from vllm.core.block.interfaces import Block, BlockAllocator
-
-BlockId = int
-RefCount = int
-
-
-class RefCounterProtocol(Protocol):
-
-    def incr(self, block_id: BlockId) -> RefCount:
-        raise NotImplementedError
-
-    def decr(self, block_id: BlockId) -> RefCount:
-        raise NotImplementedError
-
-    def get(self, block_id: BlockId) -> RefCount:
-        raise NotImplementedError
-
-
-class RefCounter(RefCounterProtocol):
-    """A class for managing reference counts for a set of block indices.
-
-    The RefCounter class maintains a dictionary that maps block indices to their
-    corresponding reference counts. It provides methods to increment, decrement,
-    and retrieve the reference count for a given block index.
-
-    Args:
-        all_block_indices (Iterable[BlockId]): An iterable of block indices
-            to initialize the reference counter with.
-    """
-
-    def __init__(self, all_block_indices: Iterable[BlockId]):
-        deduped = set(all_block_indices)
-        self._refcounts: Dict[BlockId, RefCount] = {
-            index: 0
-            for index in deduped
-        }
-
-    def incr(self, block_id: BlockId) -> RefCount:
-        assert block_id in self._refcounts
-        pre_incr_refcount = self._refcounts[block_id]
-
-        assert pre_incr_refcount >= 0
-
-        post_incr_refcount = pre_incr_refcount + 1
-        self._refcounts[block_id] = post_incr_refcount
-        return post_incr_refcount
-
-    def decr(self, block_id: BlockId) -> RefCount:
-        assert block_id in self._refcounts
-        refcount = self._refcounts[block_id]
-
-        assert refcount > 0
-        refcount -= 1
-
-        self._refcounts[block_id] = refcount
-
-        return refcount
-
-    def get(self, block_id: BlockId) -> RefCount:
-        assert block_id in self._refcounts
-        return self._refcounts[block_id]
-
-    def as_readonly(self) -> "ReadOnlyRefCounter":
-        return ReadOnlyRefCounter(self)
-
-
-class ReadOnlyRefCounter(RefCounterProtocol):
-    """A read-only view of the RefCounter class.
-
-    The ReadOnlyRefCounter class provides a read-only interface to access the
-    reference counts maintained by a RefCounter instance. It does not allow
-    modifications to the reference counts.
-
-    Args:
-        refcounter (RefCounter): The RefCounter instance to create a read-only
-            view for.
-    """
-
-    def __init__(self, refcounter: RefCounter):
-        self._refcounter = refcounter
-
-    def incr(self, block_id: BlockId) -> RefCount:
-        raise ValueError("Incr not allowed")
-
-    def decr(self, block_id: BlockId) -> RefCount:
-        raise ValueError("Decr not allowed")
-
-    def get(self, block_id: BlockId) -> RefCount:
-        return self._refcounter.get(block_id)
-
-
-class CopyOnWriteTracker:
-    """A class for tracking and managing copy-on-write operations for blocks.
-
-    The CopyOnWriteTracker class maintains a mapping of source block indices to
-        their corresponding copy-on-write destination block indices. It works in
-        conjunction with a RefCounter.
-
-    Args:
-        refcounter (RefCounter): The reference counter used to track block
-            reference counts.
-    """
-
-    def __init__(self, refcounter: RefCounterProtocol):
-        self._copy_on_writes: List[Tuple[BlockId, BlockId]] = []
-        self._refcounter = refcounter
-
-    def is_appendable(self, block: Block) -> bool:
-        """Checks if the block is shared or not. If shared, then it cannot
-        be appended and needs to be duplicated via copy-on-write
-        """
-        block_id = block.block_id
-        if block_id is None:
-            return True
-
-        refcount = self._refcounter.get(block_id)
-        return refcount <= 1
-
-    def record_cow(self, src_block_id: Optional[BlockId],
-                   trg_block_id: Optional[BlockId]) -> None:
-        """Records a copy-on-write operation from source to target block id
-        Args:
-            src_block_id (BlockId): The source block id from which to copy 
-                the data
-            trg_block_id (BlockId): The target block id to which the data
-                is copied
-        """
-        assert src_block_id is not None
-        assert trg_block_id is not None
-        self._copy_on_writes.append((src_block_id, trg_block_id))
-
-    def clear_cows(self) -> List[Tuple[BlockId, BlockId]]:
-        """Clears the copy-on-write tracking information and returns the current
-        state.
-
-        This method returns a list mapping source block indices to
-         destination block indices for the current copy-on-write operations.
-        It then clears the internal tracking information.
-
-        Returns:
-            List[Tuple[BlockId, BlockId]]: A list mapping source
-                block indices to destination block indices for the
-                current copy-on-write operations.
-        """
-        cows = self._copy_on_writes
-        self._copy_on_writes = []
-        return cows
-
-
-class BlockPool:
-    """Used to pre-allocate block objects, in order to avoid excessive python
-    object allocations/deallocations.
-    The pool starts from "pool_size" objects and will increase to more objects
-    if necessary
-
-    Note that multiple block objects may point to the same physical block id,
-    which is why this pool is needed, so that it will be easier to support
-    prefix caching and more complicated sharing of physical blocks.
-    """
-
-    def __init__(self, block_size: int, create_block: Block.Factory,
-                 allocator: BlockAllocator, pool_size: int):
-        self._block_size = block_size
-        self._create_block = create_block
-        self._allocator = allocator
-        self._pool_size = pool_size
-        assert self._pool_size >= 0
-
-        self._free_ids: Deque[int] = deque(range(self._pool_size))
-        self._pool = []
-        for i in range(self._pool_size):
-            self._pool.append(
-                self._create_block(prev_block=None,
-                                   token_ids=[],
-                                   block_size=self._block_size,
-                                   allocator=self._allocator,
-                                   block_id=None,
-                                   extra_hash=None))
-
-    def increase_pool(self):
-        """Doubles the internal pool size
-        """
-        cur_pool_size = self._pool_size
-        new_pool_size = cur_pool_size * 2
-        self._pool_size = new_pool_size
-
-        self._free_ids += deque(range(cur_pool_size, new_pool_size))
-
-        for i in range(cur_pool_size, new_pool_size):
-            self._pool.append(
-                self._create_block(prev_block=None,
-                                   token_ids=[],
-                                   block_size=self._block_size,
-                                   allocator=self._allocator,
-                                   block_id=None,
-                                   extra_hash=None))
-
-    def init_block(self,
-                   prev_block: Optional[Block],
-                   token_ids: List[int],
-                   block_size: int,
-                   physical_block_id: Optional[int],
-                   extra_hash: Optional[int] = None) -> Block:
-        if len(self._free_ids) == 0:
-            self.increase_pool()
-            assert len(self._free_ids) > 0
-
-        pool_id = self._free_ids.popleft()
-
-        block = self._pool[pool_id]
-        block.__init__(  # type: ignore[misc]
-            prev_block=prev_block,
-            token_ids=token_ids,
-            block_size=block_size,
-            allocator=block._allocator,  # type: ignore[attr-defined] 
-            block_id=physical_block_id,
-            extra_hash=extra_hash)
-        block.pool_id = pool_id  # type: ignore[attr-defined]
-        return block
-
-    def free_block(self, block: Block) -> None:
-        self._free_ids.appendleft(block.pool_id)  # type: ignore[attr-defined]
-
-
-class BlockList:
-    """This class is an optimization to allow fast-access to physical 
-    block ids. It maintains a block id list that is updated with the 
-    block list and this avoids the need to reconstruct the block id 
-    list on every iteration of the block manager
-    """
-
-    def __init__(self, blocks: List[Block]):
-        self._blocks: List[Block] = []
-        self._block_ids: List[int] = []
-
-        self.update(blocks)
-
-    def _add_block_id(self, block_id: Optional[BlockId]) -> None:
-        assert block_id is not None
-        self._block_ids.append(block_id)
-
-    def _update_block_id(self, block_index: int,
-                         new_block_id: Optional[BlockId]) -> None:
-        assert new_block_id is not None
-        self._block_ids[block_index] = new_block_id
-
-    def update(self, blocks: List[Block]):
-        self._blocks = blocks
-
-        # Cache block ids for fast query
-        self._block_ids = []
-        for block in self._blocks:
-            self._add_block_id(block.block_id)
-
-    def append_token_ids(self, block_index: int, token_ids: List[int]) -> None:
-        block = self._blocks[block_index]
-        prev_block_id = block.block_id
-
-        block.append_token_ids(token_ids)
-
-        # CoW or promotion may update the internal block_id
-        if prev_block_id != block.block_id:
-            self._update_block_id(block_index, block.block_id)
-
-    def append(self, new_block: Block):
-        self._blocks.append(new_block)
-        self._add_block_id(new_block.block_id)
-
-    def __len__(self) -> int:
-        return len(self._blocks)
-
-    def __getitem__(self, block_index: int) -> Block:
-        return self._blocks[block_index]
-
-    def __setitem__(self, block_index: int, new_block: Block) -> None:
-        self._blocks[block_index] = new_block
-        self._update_block_id(block_index, new_block.block_id)
-
-    def reset(self):
-        self._blocks = []
-        self._block_ids = []
-
-    def list(self) -> List[Block]:
-        return self._blocks
-
-    def ids(self) -> List[int]:
-        return self._block_ids
-
-
-@dataclass
-class CacheMetricData:
-    """A utility dataclass to maintain cache metric.
-    To avoid overflow, we maintain the hit rate in block granularity, so that
-    we can maintain a single hit rate for n_completed_block x block_size,
-    and calculate the real time hit rate by the following:
-    BS = The number of queries per block.
-    nB = The number of completed blocks.
-    HR = hit rate of (nB x BS) queries.
-    Q = current number of queries (< BS).
-    H = current number of hits (< BS).
-    hit rate = ((HR x nB) + (H / Q) x (Q / BS)) / (nB + Q / BS)
-    """
-    num_completed_blocks: int = 0
-    completed_block_cache_hit_rate: float = 0.0
-    num_incompleted_block_queries: int = 0
-    num_incompleted_block_hit: int = 0
-    block_size: int = 1000
-
-    def query(self, hit: bool):
-        self.num_incompleted_block_queries += 1
-        self.num_incompleted_block_hit += 1 if hit else 0
-
-        # When a block is completed, update the cache hit rate
-        # and reset the incomplete numbers.
-        if self.num_incompleted_block_queries == self.block_size:
-            hit_rate = (self.num_incompleted_block_hit /
-                        self.num_incompleted_block_queries)
-            self.completed_block_cache_hit_rate = (
-                self.completed_block_cache_hit_rate * self.num_completed_blocks
-                + hit_rate) / (self.num_completed_blocks + 1)
-            self.num_incompleted_block_queries = 0
-            self.num_incompleted_block_hit = 0
-            self.num_completed_blocks += 1
-
-    def get_hit_rate(self):
-        incomplete_ratio = self.num_incompleted_block_queries / self.block_size
-        total_blocks = self.num_completed_blocks + incomplete_ratio
-        if total_blocks == 0:
-            return 0.0
-
-        completed_block_hit, incompleted_block_hit = 0.0, 0.0
-        if self.num_completed_blocks > 0:
-            completed_block_hit = (self.completed_block_cache_hit_rate *
-                                   self.num_completed_blocks)
-        if self.num_incompleted_block_queries > 0:
-            incompleted_hit_rate = (self.num_incompleted_block_hit /
-                                    self.num_incompleted_block_queries)
-            incompleted_block_hit = (incompleted_hit_rate * incomplete_ratio)
-        return (completed_block_hit + incompleted_block_hit) / total_blocks
-
-
-def get_all_blocks_recursively(last_block: Block) -> List[Block]:
-    """Retrieves all the blocks in a sequence starting from the last block.
-
-    This function recursively traverses the sequence of blocks in reverse order,
-    starting from the given last block, and returns a list of all the blocks in
-    the sequence.
-
-    Args:
-        last_block (Block): The last block in the sequence.
-
-    Returns:
-        List[Block]: A list of all the blocks in the sequence, in the order they
-            appear.
-    """
-
-    def recurse(block: Block, lst: List[Block]) -> None:
-        if block.prev_block is not None:
-            recurse(block.prev_block, lst)
-        lst.append(block)
-
-    all_blocks: List[Block] = []
-    recurse(last_block, all_blocks)
-    return all_blocks

vllm/core/block/cpu_gpu_block_allocator.py

-# SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-
-from typing import Dict, FrozenSet, List, Optional, Tuple
-
-from vllm.core.block.interfaces import (Block, BlockAllocator, BlockId,
-                                        DeviceAwareBlockAllocator)
-from vllm.core.block.naive_block import NaiveBlock, NaiveBlockAllocator
-from vllm.core.block.prefix_caching_block import PrefixCachingBlockAllocator
-from vllm.utils import Device
-
-
-class CpuGpuBlockAllocator(DeviceAwareBlockAllocator):
-    """A block allocator that can allocate blocks on both CPU and GPU memory.
-
-    This class implements the `DeviceAwareBlockAllocator` interface and provides
-    functionality for allocating and managing blocks of memory on both CPU and
-    GPU devices.
-
-    The `CpuGpuBlockAllocator` maintains separate memory pools for CPU and GPU
-    blocks, and allows for allocation, deallocation, forking, and swapping of
-    blocks across these memory pools.
-    """
-
-    @staticmethod
-    def create(
-        allocator_type: str,
-        num_gpu_blocks: int,
-        num_cpu_blocks: int,
-        block_size: int,
-    ) -> DeviceAwareBlockAllocator:
-        """Creates a CpuGpuBlockAllocator instance with the specified
-        configuration.
-
-        This static method creates and returns a CpuGpuBlockAllocator instance
-        based on the provided parameters. It initializes the CPU and GPU block
-        allocators with the specified number of blocks, block size, and
-        allocator type.
-
-        Args:
-            allocator_type (str): The type of block allocator to use for CPU
-                and GPU blocks. Currently supported values are "naive" and
-                "prefix_caching".
-            num_gpu_blocks (int): The number of blocks to allocate for GPU
-                memory.
-            num_cpu_blocks (int): The number of blocks to allocate for CPU
-                memory.
-            block_size (int): The size of each block in number of tokens.
-
-        Returns:
-            DeviceAwareBlockAllocator: A CpuGpuBlockAllocator instance with the
-                specified configuration.
-
-        Notes:
-            - The block IDs are assigned contiguously, with GPU block IDs coming
-                before CPU block IDs.
-        """
-        reserved_blocks = 0
-        block_ids = list(
-            range(reserved_blocks, num_gpu_blocks + num_cpu_blocks))
-        num_gpu_blocks -= reserved_blocks
-        gpu_block_ids = block_ids[:num_gpu_blocks]
-        cpu_block_ids = block_ids[num_gpu_blocks:]
-
-        if allocator_type == "naive":
-            gpu_allocator: BlockAllocator = NaiveBlockAllocator(
-                create_block=NaiveBlock,  # type: ignore
-                num_blocks=num_gpu_blocks,
-                block_size=block_size,
-                block_ids=gpu_block_ids,
-            )
-
-            cpu_allocator: BlockAllocator = NaiveBlockAllocator(
-                create_block=NaiveBlock,  # type: ignore
-                num_blocks=num_cpu_blocks,
-                block_size=block_size,
-                block_ids=cpu_block_ids,
-            )
-        elif allocator_type == "prefix_caching":
-            gpu_allocator = PrefixCachingBlockAllocator(
-                num_blocks=num_gpu_blocks,
-                block_size=block_size,
-                block_ids=gpu_block_ids,
-            )
-
-            cpu_allocator = PrefixCachingBlockAllocator(
-                num_blocks=num_cpu_blocks,
-                block_size=block_size,
-                block_ids=cpu_block_ids,
-            )
-        else:
-            raise ValueError(f"Unknown allocator type {allocator_type=}")
-
-        return CpuGpuBlockAllocator(
-            cpu_block_allocator=cpu_allocator,
-            gpu_block_allocator=gpu_allocator,
-        )
-
-    def __init__(self, cpu_block_allocator: BlockAllocator,
-                 gpu_block_allocator: BlockAllocator):
-        assert not (
-            cpu_block_allocator.all_block_ids
-            & gpu_block_allocator.all_block_ids
-        ), "cpu and gpu block allocators can't have intersection of block ids"
-
-        self._allocators = {
-            Device.CPU: cpu_block_allocator,
-            Device.GPU: gpu_block_allocator,
-        }
-
-        self._swap_mapping: Dict[int, int] = {}
-        self._null_block: Optional[Block] = None
-
-        self._block_ids_to_allocator: Dict[int, BlockAllocator] = {}
-        for _, allocator in self._allocators.items():
-            for block_id in allocator.all_block_ids:
-                self._block_ids_to_allocator[block_id] = allocator
-
-    def allocate_or_get_null_block(self) -> Block:
-        if self._null_block is None:
-            self._null_block = NullBlock(
-                self.allocate_mutable_block(None, Device.GPU))
-        return self._null_block
-
-    def allocate_mutable_block(self,
-                               prev_block: Optional[Block],
-                               device: Device,
-                               extra_hash: Optional[int] = None) -> Block:
-        """Allocates a new mutable block on the specified device.
-
-        Args:
-            prev_block (Optional[Block]): The previous block to in the sequence.
-                Used for prefix hashing.
-            device (Device): The device on which to allocate the new block.
-            extra_hash (Optional[int]): The hash value of additional
-                factors, such as adapters, that influence the block hash
-                in the prefix caching block.
-
-        Returns:
-            Block: The newly allocated mutable block.
-        """
-        return self._allocators[device].allocate_mutable_block(
-            prev_block, extra_hash=extra_hash)
-
-    def allocate_immutable_blocks(
-            self,
-            prev_block: Optional[Block],
-            block_token_ids: List[List[int]],
-            device: Device,
-            extra_hash: Optional[int] = None) -> List[Block]:
-        """Allocates a new group of immutable blocks with the provided block 
-        token IDs on the specified device.
-
-        Args:
-            prev_block (Optional[Block]): The previous block in the sequence.
-                Used for prefix hashing.
-            block_token_ids (List[int]): The list of block token IDs to be 
-                stored in the new blocks.
-            device (Device): The device on which to allocate the new block.
-            extra_hash (Optional[int]): The hash value of additional
-                factors, such as adapters, that influence the block hash
-                in the prefix caching block.
-
-        Returns:
-            List[Block]: The newly allocated list of immutable blocks 
-                containing the provided block token IDs.
-        """
-        return self._allocators[device].allocate_immutable_blocks(
-            prev_block, block_token_ids, extra_hash=extra_hash)
-
-    def allocate_immutable_block(self,
-                                 prev_block: Optional[Block],
-                                 token_ids: List[int],
-                                 device: Device,
-                                 extra_hash: Optional[int] = None) -> Block:
-        """Allocates a new immutable block with the provided token IDs on the
-        specified device.
-
-        Args:
-            prev_block (Optional[Block]): The previous block in the sequence.
-                Used for prefix hashing.
-            token_ids (List[int]): The list of token IDs to be stored in the new
-                block.
-            device (Device): The device on which to allocate the new block.
-            extra_hash (Optional[int]): The hash value of additional
-                factors, such as adapters, that influence the block hash
-                in the prefix caching block.
-
-        Returns:
-            Block: The newly allocated immutable block containing the provided
-                token IDs.
-        """
-        return self._allocators[device].allocate_immutable_block(
-            prev_block, token_ids, extra_hash=extra_hash)
-
-    def free(self, block: Block) -> None:
-        """Frees the memory occupied by the given block.
-
-        Args:
-            block (Block): The block to be freed.
-        """
-        # Null block should never be freed
-        if isinstance(block, NullBlock):
-            return
-        block_id = block.block_id
-        assert block_id is not None
-        allocator = self._block_ids_to_allocator[block_id]
-        allocator.free(block)
-
-    def fork(self, last_block: Block) -> List[Block]:
-        """Creates a new sequence of blocks that shares the same underlying
-            memory as the original sequence.
-
-        Args:
-            last_block (Block): The last block in the original sequence.
-
-        Returns:
-            List[Block]: A new list of blocks that shares the same memory as the
-                original sequence.
-        """
-        # do not attempt to fork the null block
-        assert not isinstance(last_block, NullBlock)
-        block_id = last_block.block_id
-        assert block_id is not None
-        allocator = self._block_ids_to_allocator[block_id]
-        return allocator.fork(last_block)
-
-    def get_num_free_blocks(self, device: Device) -> int:
-        """Returns the number of free blocks available on the specified device.
-
-        Args:
-            device (Device): The device for which to query the number of free
-                blocks. AssertionError is raised if None is passed.
-
-        Returns:
-            int: The number of free blocks available on the specified device.
-        """
-        return self._allocators[device].get_num_free_blocks()
-
-    def get_num_total_blocks(self, device: Device) -> int:
-        return self._allocators[device].get_num_total_blocks()
-
-    def get_physical_block_id(self, device: Device, absolute_id: int) -> int:
-        """Returns the zero-offset block id on certain device given the 
-        absolute block id.
-
-        Args:
-            device (Device): The device for which to query relative block id.
-                absolute_id (int): The absolute block id for the block in 
-                whole allocator.
-
-        Returns:
-            int: The zero-offset block id on certain device.
-        """
-        return self._allocators[device].get_physical_block_id(absolute_id)
-
-    def swap(self, blocks: List[Block], src_device: Device,
-             dst_device: Device) -> Dict[int, int]:
-        """Execute the swap for the given blocks from source_device
-        on to dest_device, save the current swap mapping and append 
-        them to the accumulated `self._swap_mapping` for each 
-        scheduling move.
-
-        Args:
-            blocks: List of blocks to be swapped.
-            src_device (Device): Device to swap the 'blocks' from.
-            dst_device (Device): Device to swap the 'blocks' to.
-        
-        Returns:
-            Dict[int, int]: Swap mapping from source_device
-                on to dest_device.
-        """
-        src_block_ids = [block.block_id for block in blocks]
-        self._allocators[src_device].swap_out(blocks)
-        self._allocators[dst_device].swap_in(blocks)
-        dst_block_ids = [block.block_id for block in blocks]
-
-        current_swap_mapping: Dict[int, int] = {}
-        for src_block_id, dst_block_id in zip(src_block_ids, dst_block_ids):
-            if src_block_id is not None and dst_block_id is not None:
-                self._swap_mapping[src_block_id] = dst_block_id
-                current_swap_mapping[src_block_id] = dst_block_id
-        return current_swap_mapping
-
-    def get_num_full_blocks_touched(self, blocks: List[Block],
-                                    device: Device) -> int:
-        """Returns the number of full blocks that will be touched by
-        swapping in/out the given blocks on to the 'device'.
-
-        Args:
-            blocks: List of blocks to be swapped.
-            device (Device): Device to swap the 'blocks' on.
-
-        Returns:
-            int: the number of full blocks that will be touched by
-                swapping in/out the given blocks on to the 'device'.
-                Non full blocks are ignored when deciding the number
-                of blocks to touch.
-        """
-        return self._allocators[device].get_num_full_blocks_touched(blocks)
-
-    def clear_copy_on_writes(self) -> List[Tuple[int, int]]:
-        """Clears the copy-on-write (CoW) state and returns the mapping of
-            source to destination block IDs.
-
-        Returns:
-            List[Tuple[int, int]]: A list mapping source block IDs to 
-                destination block IDs.
-        """
-        # CoW only supported on GPU
-        device = Device.GPU
-        return self._allocators[device].clear_copy_on_writes()
-
-    def mark_blocks_as_accessed(self, block_ids: List[int],
-                                now: float) -> None:
-        """Mark blocks as accessed, only use for prefix caching."""
-        # Prefix caching only supported on GPU.
-        device = Device.GPU
-        return self._allocators[device].mark_blocks_as_accessed(block_ids, now)
-
-    def mark_blocks_as_computed(self, block_ids: List[int]) -> None:
-        """Mark blocks as accessed, only use for prefix caching."""
-        # Prefix caching only supported on GPU.
-        device = Device.GPU
-        return self._allocators[device].mark_blocks_as_computed(block_ids)
-
-    def get_common_computed_block_ids(
-            self, computed_seq_block_ids: List[List[int]]) -> List[int]:
-        # Prefix caching only supported on GPU.
-        device = Device.GPU
-        return self._allocators[device].get_common_computed_block_ids(
-            computed_seq_block_ids)
-
-    @property
-    def all_block_ids(self) -> FrozenSet[int]:
-        return frozenset(self._block_ids_to_allocator.keys())
-
-    def get_prefix_cache_hit_rate(self, device: Device) -> float:
-        """Prefix cache hit rate. -1 means not supported or disabled."""
-        assert device in self._allocators
-        return self._allocators[device].get_prefix_cache_hit_rate()
-
-    def reset_prefix_cache(self, device: Optional[Device] = None) -> bool:
-        """Reset prefix cache for specified or all devices."""
-        if device:
-            return self._allocators[device].reset_prefix_cache()
-        success = True
-        for allocator in self._allocators.values():
-            success = success and allocator.reset_prefix_cache()
-        return success
-
-    def get_and_reset_swaps(self) -> List[Tuple[int, int]]:
-        """Returns and clears the mapping of source to destination block IDs.
-        Will be called after every swapping operations for now, and after every
-        schedule when BlockManagerV2 become default. Currently not useful.
-
-        Returns:
-            List[Tuple[int, int]]: A mapping of source to destination block IDs.
-        """
-        mapping = self._swap_mapping.copy()
-        self._swap_mapping.clear()
-        return list(mapping.items())
-
-    def find_cached_blocks_prefix(
-        self,
-        block_hashes: List[int],
-        device: Device = Device.GPU,
-    ) -> List[int]:
-        return self._allocators[device].find_cached_blocks_prefix(block_hashes)
-
-
-class NullBlock(Block):
-    """
-    Null blocks are used as a placeholders for KV cache blocks that have
-    been dropped due to sliding window.
-    This implementation just wraps an ordinary block and prevents it from
-    being modified. It also allows for testing if a block is NullBlock
-    via isinstance().
-    """
-
-    def __init__(self, proxy: Block):
-        super().__init__()
-        self._proxy = proxy
-
-    def append_token_ids(self, token_ids: List[BlockId]):
-        raise ValueError("null block should not be modified")
-
-    @property
-    def block_id(self):
-        return self._proxy.block_id
-
-    @block_id.setter
-    def block_id(self, value: Optional[BlockId]):
-        raise ValueError("null block should not be modified")
-
-    @property
-    def token_ids(self) -> List[BlockId]:
-        return self._proxy.token_ids
-
-    @property
-    def num_tokens_total(self) -> int:
-        raise NotImplementedError(
-            "num_tokens_total is not used for null block")
-
-    @property
-    def num_empty_slots(self) -> BlockId:
-        return self._proxy.num_empty_slots
-
-    @property
-    def is_full(self):
-        return self._proxy.is_full
-
-    @property
-    def prev_block(self):
-        return self._proxy.prev_block
-
-    @property
-    def extra_hash(self):
-        return None
-
-    @property
-    def computed(self):
-        return self._proxy.computed
-
-    @computed.setter
-    def computed(self, value):
-        self._proxy.computed = value
-
-    @property
-    def last_accessed(self) -> float:
-        return self._proxy.last_accessed
-
-    @last_accessed.setter
-    def last_accessed(self, last_accessed_ts: float):
-        self._proxy.last_accessed = last_accessed_ts
-
-    @property
-    def content_hash(self):
-        return self._proxy.content_hash

vllm/core/block/interfaces.py

-# SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-
-from abc import ABC, abstractmethod
-from typing import Dict, FrozenSet, List, Optional, Protocol, Tuple
-
-from vllm.utils import Device
-
-BlockId = int
-
-
-class Block(ABC):
-
-    @abstractmethod
-    def append_token_ids(self, token_ids: List[int]) -> None:
-        pass
-
-    @property
-    @abstractmethod
-    def block_id(self) -> Optional[int]:
-        pass
-
-    @block_id.setter
-    @abstractmethod
-    def block_id(self, value: Optional[int]) -> None:
-        """NOTE: Do not use this API outside Block."""
-        self._block_id = value
-
-    @property
-    @abstractmethod
-    def token_ids(self) -> List[int]:
-        pass
-
-    @property
-    @abstractmethod
-    def num_tokens_total(self) -> int:
-        """The number of tokens till the current block (inclusive)
-        """
-        pass
-
-    @property
-    @abstractmethod
-    def num_empty_slots(self) -> int:
-        pass
-
-    @property
-    @abstractmethod
-    def is_full(self) -> bool:
-        pass
-
-    @property
-    @abstractmethod
-    def prev_block(self) -> Optional["Block"]:
-        pass
-
-    @property
-    @abstractmethod
-    def extra_hash(self) -> Optional[int]:
-        return None
-
-    @property
-    @abstractmethod
-    def computed(self) -> bool:
-        raise NotImplementedError
-
-    @computed.setter
-    @abstractmethod
-    def computed(self, value) -> bool:
-        """Should be only used by PrefixCacingAllocator"""
-        raise NotImplementedError
-
-    @property
-    @abstractmethod
-    def last_accessed(self) -> float:
-        raise NotImplementedError
-
-    @last_accessed.setter
-    @abstractmethod
-    def last_accessed(self, last_accessed_ts: float):
-        raise NotImplementedError
-
-    class Factory(Protocol):
-
-        @abstractmethod
-        def __call__(
-            self,
-            prev_block: Optional["Block"],
-            token_ids: List[int],
-            block_size: int,
-            allocator: "BlockAllocator",
-            block_id: Optional[int] = None,
-            computed: bool = False,
-            extra_hash: Optional[int] = None,
-        ) -> "Block":
-            pass
-
-    @property
-    @abstractmethod
-    def content_hash(self) -> Optional[int]:
-        """Return the content-based hash of the current block, or None if it is
-        not yet defined or not supported.
-
-        For the content-based hash to be defined, the current block must be
-        full.
-        """
-        return None
-
-
-class BlockAllocator(ABC):
-
-    @abstractmethod
-    def allocate_mutable_block(self, prev_block: Optional[Block],
-                               extra_hash: Optional[int]) -> Block:
-        pass
-
-    @abstractmethod
-    def allocate_immutable_block(self, prev_block: Optional[Block],
-                                 token_ids: List[int],
-                                 extra_hash: Optional[int]) -> Block:
-        pass
-
-    @abstractmethod
-    def allocate_immutable_blocks(self, prev_block: Optional[Block],
-                                  block_token_ids: List[List[int]],
-                                  extra_hash: Optional[int]) -> List[Block]:
-        pass
-
-    @abstractmethod
-    def free(self, block: Block) -> None:
-        pass
-
-    @abstractmethod
-    def fork(self, last_block: Block) -> List[Block]:
-        pass
-
-    @abstractmethod
-    def get_num_total_blocks(self) -> int:
-        pass
-
-    @abstractmethod
-    def get_num_free_blocks(self) -> int:
-        pass
-
-    @abstractmethod
-    def get_physical_block_id(self, absolute_id: int) -> int:
-        pass
-
-    @abstractmethod
-    def swap_out(self, blocks: List[Block]) -> None:
-        pass
-
-    @abstractmethod
-    def swap_in(self, blocks: List[Block]) -> None:
-        pass
-
-    @property
-    @abstractmethod
-    def all_block_ids(self) -> FrozenSet[int]:
-        pass
-
-    @abstractmethod
-    def clear_copy_on_writes(self) -> List[Tuple[int, int]]:
-        pass
-
-    @abstractmethod
-    def mark_blocks_as_accessed(self, block_ids: List[int],
-                                now: float) -> None:
-        pass
-
-    @abstractmethod
-    def mark_blocks_as_computed(self, block_ids: List[int]) -> None:
-        pass
-
-    @abstractmethod
-    def get_common_computed_block_ids(
-            self, computed_seq_block_ids: List[List[int]]) -> List[int]:
-        pass
-
-    @abstractmethod
-    def cow_block_if_not_appendable(self, block: Block) -> BlockId:
-        """NOTE: This should not be used besides Block"""
-        pass
-
-    @abstractmethod
-    def promote_to_immutable_block(self, block: Block) -> BlockId:
-        """NOTE: This should not be used besides Block"""
-        pass
-
-    @abstractmethod
-    def get_num_full_blocks_touched(self, blocks: List[Block]) -> int:
-        pass
-
-    @abstractmethod
-    def get_prefix_cache_hit_rate(self) -> float:
-        """Prefix cache hit rate. -1 means not supported or disabled."""
-        pass
-
-    @abstractmethod
-    def reset_prefix_cache(self) -> bool:
-        """Reset prefix cache."""
-        pass
-
-    class NoFreeBlocksError(ValueError):
-        pass
-
-    @abstractmethod
-    def find_cached_blocks_prefix(
-        self,
-        block_hashes: List[int],
-    ) -> List[int]:
-        pass
-
-
-class DeviceAwareBlockAllocator(ABC):
-
-    @abstractmethod
-    def allocate_mutable_block(self,
-                               prev_block: Optional[Block],
-                               device: Device,
-                               extra_hash: Optional[int] = None) -> Block:
-        pass
-
-    @abstractmethod
-    def allocate_immutable_block(self,
-                                 prev_block: Optional[Block],
-                                 token_ids: List[int],
-                                 device: Device,
-                                 extra_hash: Optional[int] = None) -> Block:
-        pass
-
-    @abstractmethod
-    def allocate_immutable_blocks(
-        self,
-        prev_block: Optional[Block],
-        block_token_ids: List[List[int]],
-        device: Device,
-        extra_hash: Optional[int] = None,
-    ) -> List[Block]:
-        pass
-
-    @abstractmethod
-    def get_num_free_blocks(self, device: Device) -> int:
-        pass
-
-    @abstractmethod
-    def get_num_total_blocks(self, device: Device) -> int:
-        pass
-
-    @abstractmethod
-    def free(self, block: Block) -> None:
-        pass
-
-    @abstractmethod
-    def fork(self, last_block: Block) -> List[Block]:
-        pass
-
-    @property
-    @abstractmethod
-    def all_block_ids(self) -> FrozenSet[int]:
-        pass
-
-    @abstractmethod
-    def clear_copy_on_writes(self) -> List[Tuple[int, int]]:
-        pass
-
-    @abstractmethod
-    def mark_blocks_as_accessed(self, block_ids: List[int],
-                                now: float) -> None:
-        pass
-
-    @abstractmethod
-    def mark_blocks_as_computed(self, block_ids: List[int]) -> None:
-        pass
-
-    @abstractmethod
-    def get_common_computed_block_ids(
-            self, computed_seq_block_ids: List[List[int]]) -> List[int]:
-        pass
-
-    @abstractmethod
-    def get_num_full_blocks_touched(self, blocks: List[Block],
-                                    device: Device) -> int:
-        pass
-
-    @abstractmethod
-    def swap(self, blocks: List[Block], src_device: Device,
-             dst_device: Device) -> Dict[int, int]:
-        pass
-
-    @abstractmethod
-    def get_physical_block_id(self, device: Device, absolute_id: int) -> int:
-        pass
-
-    @abstractmethod
-    def allocate_or_get_null_block(self) -> Block:
-        """
-        Null blocks are used as a placeholders for KV cache blocks that have
-        been dropped due to sliding window.
-        There is at most one null block per allocator.
-        """
-        pass
-
-    @abstractmethod
-    def get_prefix_cache_hit_rate(self, device: Device) -> float:
-        """Prefix cache hit rate. -1 means not supported or disabled."""
-        pass
-
-    @abstractmethod
-    def reset_prefix_cache(self, device: Optional[Device] = None) -> bool:
-        """Reset prefix cache."""
-        pass
-
-    @abstractmethod
-    def find_cached_blocks_prefix(
-        self,
-        block_hashes: List[int],
-        device: Device = Device.GPU,
-    ) -> List[int]:
-        pass

vllm/core/block/naive_block.py

-# SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-
-from collections import deque
-from typing import Deque, FrozenSet, Iterable, List, Optional, Tuple, Union
-
-from vllm.core.block.common import (BlockPool, CopyOnWriteTracker, RefCounter,
-                                    get_all_blocks_recursively)
-from vllm.core.block.interfaces import Block, BlockAllocator, BlockId, Device
-
-Refcount = int
-
-
-class NaiveBlockAllocator(BlockAllocator):
-    """A simple block allocator that manages blocks of memory without prefix
-    caching.
-
-    Args:
-        create_block (Block.Factory): A factory function for creating new
-            blocks. This is used when a NaiveBlockAllocator is composed within
-            a prefix caching allocator -- the naive block allocator must
-            construct prefix caching blocks (but shouldn't know anything else
-            about them).
-        num_blocks (int): The total number of blocks to manage.
-        block_size (int): The size of each block in tokens.
-        block_ids (Optional[Iterable[int]], optional): An optional iterable of
-            block IDs. If not provided, block IDs will be assigned sequentially
-            from 0 to num_blocks - 1.
-    """
-
-    def __init__(
-        self,
-        create_block: Block.Factory,
-        num_blocks: int,
-        block_size: int,
-        block_ids: Optional[Iterable[int]] = None,
-        block_pool: Optional[BlockPool] = None,
-    ):
-        if block_ids is None:
-            block_ids = range(num_blocks)
-
-        self._free_block_indices: Deque[BlockId] = deque(block_ids)
-        self._all_block_indices = frozenset(block_ids)
-        assert len(self._all_block_indices) == num_blocks
-
-        self._refcounter = RefCounter(
-            all_block_indices=self._free_block_indices)
-        self._block_size = block_size
-
-        self._cow_tracker = CopyOnWriteTracker(
-            refcounter=self._refcounter.as_readonly())
-
-        if block_pool is None:
-            extra_factor = 4
-            # Pre-allocate "num_blocks * extra_factor" block objects.
-            # The "* extra_factor" is a buffer to allow more block objects
-            # than physical blocks
-            self._block_pool = BlockPool(self._block_size, create_block, self,
-                                         num_blocks * extra_factor)
-        else:
-            # In this case, the block pool is provided by the caller,
-            # which means that there is most likely a need to share
-            # a block pool between allocators
-            self._block_pool = block_pool
-
-    def allocate_immutable_block(self,
-                                 prev_block: Optional[Block],
-                                 token_ids: List[int],
-                                 extra_hash: Optional[int] = None,
-                                 device: Optional[Device] = None) -> Block:
-        """Allocates a new immutable block with the given token IDs, linked to
-        the previous block.
-
-        Args:
-            prev_block (Optional[Block]): The previous block in the sequence. If
-                None, then the block to be allocated is the first block in the
-                sequence.
-            token_ids (List[int]): The token IDs to be stored in the new block.
-
-        Returns:
-            Block: The newly allocated immutable block.
-        """
-        assert device is None
-        block = self.allocate_mutable_block(prev_block=prev_block)
-        block.append_token_ids(token_ids)
-        return block
-
-    def allocate_immutable_blocks(
-            self,
-            prev_block: Optional[Block],
-            block_token_ids: List[List[int]],
-            extra_hash: Optional[int] = None,
-            device: Optional[Device] = None) -> List[Block]:
-        assert device is None
-        num_blocks = len(block_token_ids)
-
-        block_ids = []
-        for i in range(num_blocks):
-            block_ids.append(self._allocate_block_id())
-
-        blocks = []
-        for i in range(num_blocks):
-            prev_block = self._block_pool.init_block(
-                prev_block=prev_block,
-                token_ids=block_token_ids[i],
-                block_size=self._block_size,
-                physical_block_id=block_ids[i])
-            blocks.append(prev_block)
-
-        return blocks
-
-    def allocate_mutable_block(self,
-                               prev_block: Optional[Block],
-                               extra_hash: Optional[int] = None,
-                               device: Optional[Device] = None) -> Block:
-        """Allocates a new mutable block, linked to the previous block.
-
-        Args:
-            prev_block (Optional[Block]): The previous block in the sequence. If
-                None, then the block to be allocated is the first block in the
-                sequence.
-
-        Returns:
-            Block: The newly allocated mutable block.
-        """
-        assert device is None
-        block_id = self._allocate_block_id()
-        block = self._block_pool.init_block(prev_block=prev_block,
-                                            token_ids=[],
-                                            block_size=self._block_size,
-                                            physical_block_id=block_id)
-        return block
-
-    def _allocate_block_id(self) -> BlockId:
-        if not self._free_block_indices:
-            raise BlockAllocator.NoFreeBlocksError()
-
-        block_id = self._free_block_indices.popleft()
-        self._refcounter.incr(block_id)
-        return block_id
-
-    def _free_block_id(self, block: Union[Block, BlockId]) -> None:
-        if isinstance(block, Block):
-            block_id = block.block_id
-            block.block_id = None
-        else:
-            block_id = block
-        assert block_id is not None
-
-        refcount = self._refcounter.decr(block_id)
-        if refcount == 0:
-            self._free_block_indices.appendleft(block_id)
-
-    def free(self, block: Block, keep_block_object: bool = False) -> None:
-        # Release the physical block id
-        self._free_block_id(block)
-
-        # Release the block object
-        if not keep_block_object:
-            self._block_pool.free_block(block)
-
-    def free_block_id(self, block_id: BlockId) -> None:
-        self._free_block_id(block_id)
-
-    def fork(self, last_block: Block) -> List[Block]:
-        """Creates a new sequence of blocks that shares the same underlying
-        memory as the original sequence.
-
-        Args:
-            last_block (Block): The last block in the original sequence.
-
-        Returns:
-            List[Block]: The new sequence of blocks that shares the same memory
-                as the original sequence.
-        """
-        source_blocks = get_all_blocks_recursively(last_block)
-
-        forked_blocks: List[Block] = []
-        prev_block = None
-        for block in source_blocks:
-
-            # Increment refcount for each block.
-            assert block.block_id is not None
-            refcount = self._refcounter.incr(block.block_id)
-            assert refcount != 1, "can't fork freed block"
-
-            forked_block = self._block_pool.init_block(
-                prev_block=prev_block,
-                token_ids=block.token_ids,
-                block_size=self._block_size,
-                physical_block_id=block.block_id)
-
-            forked_blocks.append(forked_block)
-            prev_block = forked_blocks[-1]
-
-        return forked_blocks
-
-    def get_num_free_blocks(self) -> int:
-        return len(self._free_block_indices)
-
-    def get_num_total_blocks(self) -> int:
-        return len(self._all_block_indices)
-
-    def get_physical_block_id(self, absolute_id: int) -> int:
-        """Returns the zero-offset block id on certain block allocator
-        given the absolute block id.
-
-        Args:
-            absolute_id (int): The absolute block id for the block 
-                in whole allocator.
-
-        Returns:
-            int: The zero-offset block id on certain device.
-        """
-        return sorted(self._all_block_indices).index(absolute_id)
-
-    @property
-    def refcounter(self):
-        return self._refcounter
-
-    @property
-    def all_block_ids(self) -> FrozenSet[int]:
-        return self._all_block_indices
-
-    def cow_block_if_not_appendable(self, block: Block) -> BlockId:
-        """Performs a copy-on-write operation on the given block if it is not
-        appendable.
-
-        Args:
-            block (Block): The block to check for copy-on-write.
-
-        Returns:
-            BlockId: The block index of the new block if a copy-on-write 
-                operation was performed, or the original block index if
-                no copy-on-write was necessary.
-        """
-        src_block_id = block.block_id
-        assert src_block_id is not None
-
-        if self._cow_tracker.is_appendable(block):
-            return src_block_id
-
-        self._free_block_id(block)
-        trg_block_id = self._allocate_block_id()
-
-        self._cow_tracker.record_cow(src_block_id, trg_block_id)
-
-        return trg_block_id
-
-    def clear_copy_on_writes(self) -> List[Tuple[BlockId, BlockId]]:
-        """Returns the copy-on-write source->destination mapping and clears it.
-
-        Returns:
-            List[Tuple[BlockId, BlockId]]: A list mapping source
-                block indices to destination block indices.
-        """
-        return self._cow_tracker.clear_cows()
-
-    def mark_blocks_as_accessed(self, block_ids: List[int],
-                                now: float) -> None:
-        """Mark blocks as accessed, used in prefix caching.
-
-        Since the naive allocator does not implement prefix caching, we do
-        nothing.
-        """
-        pass
-
-    def mark_blocks_as_computed(self, block_ids: List[int]) -> None:
-        """Mark blocks as computed, used in prefix caching.
-
-        Since the naive allocator does not implement prefix caching, we do
-        nothing.
-        """
-        pass
-
-    def get_common_computed_block_ids(
-            self, computed_seq_block_ids: List[List[int]]) -> List[int]:
-        """Determine blocks that can be skipped in prefill.
-
-        Since the naive allocator does not support prefix caching, always return
-        an empty list.
-        """
-        return []
-
-    def promote_to_immutable_block(self, block: Block) -> BlockId:
-        raise NotImplementedError("There is no promotion for naive blocks")
-
-    def get_num_full_blocks_touched(self, blocks: List[Block]) -> int:
-        """Returns the number of full blocks that will be touched by
-        swapping in/out.
-
-        Args:
-            blocks: List of blocks to be swapped.
-        Returns:
-            int: the number of full blocks that will be touched by
-                swapping in/out the given blocks. Non full blocks are ignored
-                when deciding the number of blocks to touch.
-        """
-        # NOTE: for naive block, we use set to eliminate common blocks among
-        # seqs, also we compare the empty slots in the mutable blocks with
-        # lookahead slots to get the number of unique new block that are
-        # needed.
-        old_block_set = set()
-        for block in blocks:
-            if block.is_full:
-                old_block_set.add(block)
-        return len(old_block_set)
-
-    def swap_out(self, blocks: List[Block]) -> None:
-        for block in blocks:
-            self._free_block_id(block)
-
-    def swap_in(self, blocks: List[Block]) -> None:
-        for block in blocks:
-            # Here we allocate either immutable or mutable block and then
-            # extract its block_id. Note that the block object is released
-            # and the block_id is assigned to "block" to allow reusing the
-            # existing "block" object
-            if block.is_full:
-                tmp_block = self.allocate_immutable_block(
-                    prev_block=block.prev_block, token_ids=block.token_ids)
-            else:
-                tmp_block = self.allocate_mutable_block(
-                    prev_block=block.prev_block)
-                tmp_block.append_token_ids(block.token_ids)
-
-            block_id = tmp_block.block_id
-            tmp_block.block_id = None
-            self._block_pool.free_block(tmp_block)
-
-            block.block_id = block_id  # Assign block_id
-
-    def get_prefix_cache_hit_rate(self) -> float:
-        return -1
-
-    def reset_prefix_cache(self) -> bool:
-        """No prefix cache for naive block allocator."""
-        return True
-
-    def find_cached_blocks_prefix(self, block_hashes: List[int]) -> List[int]:
-        # Not applicable for naive block allocator.
-        return []
-
-
-class NaiveBlock(Block):
-    """An implementation of the Block class that does not support prefix
-    caching.
-
-    The NaiveBlock class represents a block of token IDs with a fixed size. It
-    provides methods for appending token IDs to the block and manages copy-on
-    -write operations when necessary.
-
-    Args:
-        prev_block (Block): The previous block in the sequence.
-        token_ids (List[int]): The initial token IDs to be stored in the block.
-        block_size (int): The maximum number of token IDs that can be stored in
-            the block.
-        allocator (BlockAllocator): The block allocator associated with this
-            block.
-        block_id (Optional[int], optional): The physical block index
-            of this block. Defaults to None, which means no allocation has been
-            made.
-        _cow_target (Optional[Block], optional): The copy-on-write target block.
-            If not provided, it defaults to self.
-    """
-
-    def __init__(self,
-                 prev_block: Optional[Block],
-                 token_ids: List[int],
-                 block_size: int,
-                 allocator: BlockAllocator,
-                 block_id: Optional[int] = None,
-                 _cow_target: Optional[Block] = None,
-                 extra_hash: Optional[int] = None):
-        self._token_ids: List[int] = []
-        self._block_size = block_size
-        self._prev_block = prev_block
-        self._block_id = block_id
-        self._allocator = allocator
-        self._cow_target = _cow_target if _cow_target is not None else self
-
-        self._append_token_ids_no_cow(token_ids)
-
-    def append_token_ids(self, token_ids: List[int]) -> None:
-        """Appends the given token IDs to the block and performs a 
-        copy-on-write if necessary.
-
-        Args:
-            token_ids (Optional[List[int]]): The token IDs to be appended 
-                to the block.
-        """
-        self._append_token_ids_no_cow(token_ids)
-
-        if self._block_id is not None:
-            self._block_id = (self._allocator.cow_block_if_not_appendable(
-                self._cow_target))
-
-    def _append_token_ids_no_cow(self, token_ids: List[int]) -> None:
-        """Appends the given token IDs to the block
-
-        Args:
-            token_ids (List[int]): The token IDs to be appended to the block.
-        """
-        if len(token_ids) == 0:
-            return
-
-        assert len(token_ids) <= self.num_empty_slots
-
-        self._token_ids.extend(token_ids)
-
-    @property
-    def computed(self) -> bool:
-        raise NotImplementedError
-
-    @computed.setter
-    def computed(self, value) -> None:
-        raise NotImplementedError
-
-    @property
-    def last_accessed(self) -> float:
-        raise NotImplementedError
-
-    @last_accessed.setter
-    def last_accessed(self, last_accessed_ts: float):
-        raise NotImplementedError
-
-    @property
-    def block_id(self) -> Optional[int]:
-        return self._block_id
-
-    @block_id.setter
-    def block_id(self, value: Optional[int]) -> None:
-        self._block_id = value
-
-    @property
-    def is_full(self) -> bool:
-        return self.num_empty_slots == 0
-
-    @property
-    def num_empty_slots(self) -> int:
-        return self._block_size - len(self.token_ids)
-
-    @property
-    def token_ids(self) -> List[int]:
-        return self._token_ids
-
-    @property
-    def num_tokens_total(self) -> int:
-        raise NotImplementedError(
-            "num_tokens_total is not used for naive block")
-
-    @property
-    def block_size(self) -> int:
-        return self._block_size
-
-    @property
-    def prev_block(self) -> Optional["Block"]:
-        return self._prev_block
-
-    @property
-    def extra_hash(self):
-        return None
-
-    @property
-    def content_hash(self) -> Optional[int]:
-        return None

vllm/core/block/utils.py

-# SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-"""Block manager utils."""
-from vllm.sequence import SequenceGroup
-from vllm.utils import (STR_NOT_IMPL_ENC_DEC_PREFIX_CACHE,
-                        STR_NOT_IMPL_ENC_DEC_SWA)
-
-
-def check_no_caching_or_swa_for_blockmgr_encdec(
-        block_mgr, seq_group: SequenceGroup) -> None:
-    '''
-    Enforce that prefix caching & sliding-window attention (SWA)
-    are currently unsupported *specifically* for encoder/decoder models.
-
-    Raises NotImplementedError if unsupported scenario is detected.
-
-    Arguments:
-
-    * block_mgr: BlockSpaceManager instance
-    * seq_group: SequenceGroup passed to block_mgr
-    '''
-
-    if seq_group.is_encoder_decoder():
-        if block_mgr.max_block_sliding_window is not None:
-            raise NotImplementedError(STR_NOT_IMPL_ENC_DEC_SWA)
-
-        if block_mgr.enable_caching:
-            raise NotImplementedError(STR_NOT_IMPL_ENC_DEC_PREFIX_CACHE)