scheduler.py

"""
Copyright 2023-2024 SGLang Team
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""

"""A scheduler that manages a tensor parallel GPU worker."""

import json
import logging
import os
import threading
import time
import warnings
from collections import deque
from types import SimpleNamespace
from typing import List, Optional, Union

import torch
import zmq

from sglang.global_config import global_config
from sglang.srt.configs.model_config import ModelConfig
from sglang.srt.constrained.grammar import GrammarCache
from sglang.srt.hf_transformers_utils import get_processor, get_tokenizer
from sglang.srt.layers.logits_processor import LogitsProcessorOutput
from sglang.srt.managers.io_struct import (
    AbortReq,
    BatchEmbeddingOut,
    BatchTokenIDOut,
    FlushCacheReq,
    GetMemPoolSizeReq,
    GetMemPoolSizeReqOutput,
    ProfileReq,
    TokenizedEmbeddingReqInput,
    TokenizedGenerateReqInput,
    TokenizedRewardReqInput,
    UpdateWeightReqInput,
    UpdateWeightReqOutput,
)
from sglang.srt.managers.schedule_batch import (
    FINISH_ABORT,
    BaseFinishReason,
    ImageInputs,
    Req,
    ScheduleBatch,
    global_server_args_dict,
)
from sglang.srt.managers.schedule_policy import (
    AddReqResult,
    PrefillAdder,
    SchedulePolicy,
)
from sglang.srt.managers.tp_worker import TpModelWorker
from sglang.srt.managers.tp_worker_overlap_thread import TpModelWorkerClient
from sglang.srt.mem_cache.chunk_cache import ChunkCache
from sglang.srt.mem_cache.radix_cache import RadixCache
from sglang.srt.server_args import PortArgs, ServerArgs
from sglang.srt.utils import (
    broadcast_pyobj,
    configure_logger,
    get_zmq_socket,
    is_generation_model,
    is_multimodal_model,
    kill_parent_process,
    set_random_seed,
    suppress_other_loggers,
)
from sglang.utils import get_exception_traceback

logger = logging.getLogger(__name__)

# Crash on warning if we are running CI tests
crash_on_warning = os.getenv("SGLANG_IS_IN_CI", "false") == "true"

# Test retract decode
test_retract = os.getenv("SGLANG_TEST_RETRACT", "false") == "true"


class Scheduler:
    """A scheduler that manages a tensor parallel GPU worker."""

    def __init__(
        self,
        server_args: ServerArgs,
        port_args: PortArgs,
        gpu_id: int,
        tp_rank: int,
        dp_rank: Optional[int],
    ):
        # Parse args
        self.server_args = server_args
        self.tp_rank = tp_rank
        self.tp_size = server_args.tp_size
        self.schedule_policy = server_args.schedule_policy
        self.disable_regex_jump_forward = server_args.disable_regex_jump_forward
        self.lora_paths = server_args.lora_paths
        self.max_loras_per_batch = server_args.max_loras_per_batch
        self.enable_overlap = server_args.enable_overlap_schedule
        self.skip_tokenizer_init = server_args.skip_tokenizer_init

        # Init inter-process communication
        context = zmq.Context(2)

        if self.tp_rank == 0:
            self.recv_from_tokenizer = get_zmq_socket(
                context, zmq.PULL, port_args.scheduler_input_ipc_name
            )

            if server_args.skip_tokenizer_init:
                # Directly send to the tokenizer/api
                self.send_to_detokenizer = get_zmq_socket(
                    context, zmq.PUSH, port_args.tokenizer_ipc_name
                )
            else:
                # Send to the detokenizer
                self.send_to_detokenizer = get_zmq_socket(
                    context, zmq.PUSH, port_args.detokenizer_ipc_name
                )
        else:
            self.recv_from_tokenizer = None
            self.send_to_detokenizer = SimpleNamespace(send_pyobj=lambda x: None)

        # Init tokenizer
        self.model_config = ModelConfig(
            server_args.model_path,
            server_args.trust_remote_code,
            context_length=server_args.context_length,
            model_override_args=json.loads(server_args.json_model_override_args),
        )

        if server_args.skip_tokenizer_init:
            self.tokenizer = self.processor = None
        else:
            if is_multimodal_model(self.model_config.hf_config.architectures):
                self.processor = get_processor(
                    server_args.tokenizer_path,
                    tokenizer_mode=server_args.tokenizer_mode,
                    trust_remote_code=server_args.trust_remote_code,
                )
                self.tokenizer = self.processor.tokenizer
            else:
                self.tokenizer = get_tokenizer(
                    server_args.tokenizer_path,
                    tokenizer_mode=server_args.tokenizer_mode,
                    trust_remote_code=server_args.trust_remote_code,
                )
        self.is_generation = is_generation_model(
            self.model_config.hf_config.architectures, self.server_args.is_embedding
        )

        # Launch a tensor parallel worker
        if self.enable_overlap:
            TpWorkerClass = TpModelWorkerClient
        else:
            TpWorkerClass = TpModelWorker

        self.tp_worker = TpWorkerClass(
            server_args=server_args,
            gpu_id=gpu_id,
            tp_rank=tp_rank,
            dp_rank=dp_rank,
            nccl_port=port_args.nccl_port,
        )

        # Get token and memory info from the model worker
        (
            self.max_total_num_tokens,
            self.max_prefill_tokens,
            self.max_running_requests,
            self.max_req_len,
            self.max_req_input_len,
            self.random_seed,
            self.device,
            worker_global_server_args_dict,
            _,
            _,
            _,
        ) = self.tp_worker.get_worker_info()
        self.tp_cpu_group = self.tp_worker.get_tp_cpu_group()
        self.pad_input_ids_func = self.tp_worker.get_pad_input_ids_func()
        global_server_args_dict.update(worker_global_server_args_dict)
        set_random_seed(self.random_seed)

        # Print debug info
        logger.info(
            f"max_total_num_tokens={self.max_total_num_tokens}, "
            f"max_prefill_tokens={self.max_prefill_tokens}, "
            f"max_running_requests={self.max_running_requests}, "
            f"context_len={self.model_config.context_len}"
        )

        # Init memory pool and cache
        self.req_to_token_pool, self.token_to_kv_pool = self.tp_worker.get_memory_pool()

        if (
            server_args.chunked_prefill_size is not None
            and server_args.disable_radix_cache
        ):
            self.tree_cache = ChunkCache(
                req_to_token_pool=self.req_to_token_pool,
                token_to_kv_pool=self.token_to_kv_pool,
            )
        else:
            self.tree_cache = RadixCache(
                req_to_token_pool=self.req_to_token_pool,
                token_to_kv_pool=self.token_to_kv_pool,
                disable=server_args.disable_radix_cache,
            )
        self.tree_cache_metrics = {"total": 0, "hit": 0}
        self.policy = SchedulePolicy(self.schedule_policy, self.tree_cache)

        # Init running status
        self.waiting_queue: List[Req] = []
        self.running_batch: Optional[ScheduleBatch] = None
        self.cur_batch: Optional[ScheduleBatch] = None
        self.forward_ct = 0
        self.forward_ct_decode = 0
        self.num_generated_tokens = 0
        self.last_stats_tic = time.time()
        self.stream_interval = server_args.stream_interval

        # Init chunked prefill
        self.chunked_prefill_size = server_args.chunked_prefill_size
        self.being_chunked_req = None
        self.is_mixed_chunk = (
            self.chunked_prefill_size is not None and server_args.enable_mixed_chunk
        )

        # Init the FSM cache for constrained generation
        self.grammar_cache = None

        if not server_args.skip_tokenizer_init:
            self.grammar_cache = GrammarCache(
                server_args.tokenizer_path,
                {
                    "tokenizer_mode": server_args.tokenizer_mode,
                    "trust_remote_code": server_args.trust_remote_code,
                },
                skip_tokenizer_init=server_args.skip_tokenizer_init,
                whitespace_patterns=server_args.constrained_json_whitespace_pattern,
                backend=server_args.grammar_backend,
                allow_jump=not server_args.disable_regex_jump_forward,
            )

        # Init new token estimation
        assert (
            server_args.schedule_conservativeness >= 0
        ), "Invalid schedule_conservativeness"

        self.init_new_token_ratio = min(
            global_config.default_init_new_token_ratio
            * server_args.schedule_conservativeness,
            1.0,
        )
        self.min_new_token_ratio = min(
            self.init_new_token_ratio
            * global_config.default_min_new_token_ratio_factor,
            1.0,
        )
        self.new_token_ratio_decay = (
            self.init_new_token_ratio - self.min_new_token_ratio
        ) / global_config.default_new_token_ratio_decay_steps
        self.new_token_ratio = self.init_new_token_ratio

        self.batch_is_full = False

        # Init watchdog thread
        self.watchdog_timeout = server_args.watchdog_timeout
        t = threading.Thread(target=self.watchdog_thread, daemon=True)
        t.start()

        # Init profiler
        if os.getenv("SGLANG_TORCH_PROFILER_DIR", "") == "":
            self.profiler = None
        else:
            self.torch_profiler_trace_dir = os.getenv("SGLANG_TORCH_PROFILER_DIR")
            logger.info(
                "Profiling enabled. Traces will be saved to: %s",
                self.torch_profiler_trace_dir,
            )
            self.profiler = torch.profiler.profile(
                activities=[
                    torch.profiler.ProfilerActivity.CPU,
                    torch.profiler.ProfilerActivity.CUDA,
                ],
                with_stack=True,
            )

    def watchdog_thread(self):
        self.watchdog_last_forward_ct = 0
        self.watchdog_last_time = time.time()

        while True:
            if self.cur_batch is not None:
                if self.watchdog_last_forward_ct == self.forward_ct:
                    if time.time() > self.watchdog_last_time + self.watchdog_timeout:
                        logger.error(f"Watchdog timeout ({self.watchdog_timeout=})")
                        break
                else:
                    self.watchdog_last_forward_ct = self.forward_ct
                    self.watchdog_last_time = time.time()
            time.sleep(self.watchdog_timeout / 2)

        kill_parent_process()

    @torch.inference_mode()
    def event_loop_normal(self):
        """A normal blocking scheduler loop."""
        self.last_batch = None

        while True:
            recv_reqs = self.recv_requests()
            self.process_input_requests(recv_reqs)

            batch = self.get_next_batch_to_run()
            self.cur_batch = batch

            if batch:
                result = self.run_batch(batch)
                self.process_batch_result(batch, result)

                # Decode multiple steps to reduce the overhead
                if batch.forward_mode.is_decode():
                    for _ in range(self.server_args.num_continuous_decode_steps - 1):
                        if not self.running_batch:
                            break
                        self.update_running_batch()
                        if not self.running_batch:
                            break
                        result = self.run_batch(batch)
                        self.process_batch_result(batch, result)
            else:
                self.check_memory()
                self.new_token_ratio = self.init_new_token_ratio

            self.last_batch = batch

    @torch.inference_mode()
    def event_loop_overlap(self):
        """A scheduler loop that overlaps the CPU processing and GPU computation."""
        result_queue = deque()

        self.last_batch = None
        self.running_batch = None

        while True:
            recv_reqs = self.recv_requests()
            self.process_input_requests(recv_reqs)

            batch = self.get_next_batch_to_run()
            self.cur_batch = batch
            if batch:
                result = self.run_batch(batch)
                result_queue.append((batch.copy(), result))

            if self.last_batch:
                tmp_batch, tmp_result = result_queue.popleft()
                self.process_batch_result(tmp_batch, tmp_result)
            elif batch is None:
                self.check_memory()
                self.new_token_ratio = self.init_new_token_ratio

            self.last_batch = batch

    def recv_requests(self):
        if self.tp_rank == 0:
            recv_reqs = []

            while True:
                try:
                    recv_req = self.recv_from_tokenizer.recv_pyobj(zmq.NOBLOCK)
                except zmq.ZMQError:
                    break
                recv_reqs.append(recv_req)
        else:
            recv_reqs = None

        if self.tp_size != 1:
            recv_reqs = broadcast_pyobj(recv_reqs, self.tp_rank, self.tp_cpu_group)
        return recv_reqs

    def process_input_requests(self, recv_reqs: List):
        for recv_req in recv_reqs:
            if isinstance(recv_req, TokenizedGenerateReqInput):
                self.handle_generate_request(recv_req)
            elif isinstance(
                recv_req, (TokenizedEmbeddingReqInput, TokenizedRewardReqInput)
            ):
                self.handle_embedding_request(recv_req)
            elif isinstance(recv_req, FlushCacheReq):
                self.flush_cache()
            elif isinstance(recv_req, AbortReq):
                self.abort_request(recv_req)
            elif isinstance(recv_req, UpdateWeightReqInput):
                success, message = self.update_weights(recv_req)
                self.send_to_detokenizer.send_pyobj(
                    UpdateWeightReqOutput(success, message)
                )
            elif isinstance(recv_req, ProfileReq):
                if recv_req == ProfileReq.START_PROFILE:
                    self.start_profile()
                else:
                    self.stop_profile()
            elif isinstance(recv_req, GetMemPoolSizeReq):
                self.send_to_detokenizer.send_pyobj(
                    GetMemPoolSizeReqOutput(self.max_total_num_tokens)
                )
            else:
                raise ValueError(f"Invalid request: {recv_req}")

    def handle_generate_request(
        self,
        recv_req: TokenizedGenerateReqInput,
    ):
        req = Req(
            recv_req.rid,
            recv_req.input_text,
            recv_req.input_ids,
            recv_req.sampling_params,
            lora_path=recv_req.lora_path,
        )
        req.tokenizer = self.tokenizer

        # Image inputs
        if recv_req.image_inputs is not None:
            req.image_inputs = ImageInputs.from_dict(
                recv_req.image_inputs, self.model_config.vocab_size
            )
            req.origin_input_ids = self.pad_input_ids_func(
                req.origin_input_ids_unpadded, req.image_inputs
            )

        req.return_logprob = recv_req.return_logprob
        req.top_logprobs_num = recv_req.top_logprobs_num
        req.stream = recv_req.stream
        req.logprob_start_len = recv_req.logprob_start_len

        if req.logprob_start_len == -1:
            # By default, only return the logprobs for output tokens
            req.logprob_start_len = len(recv_req.input_ids) - 1

        # Init regex FSM or BNF
        if (
            req.sampling_params.json_schema is not None
            or req.sampling_params.regex is not None
        ):
            assert self.grammar_cache is not None
            if req.sampling_params.json_schema is not None:
                req.grammar = self.grammar_cache.query(
                    ("json", req.sampling_params.json_schema),
                    self.model_config.vocab_size,
                )
            elif req.sampling_params.regex is not None:
                req.grammar = self.grammar_cache.query(
                    ("regex", req.sampling_params.regex), self.model_config.vocab_size
                )

        # Truncate prompts that are too long
        if len(req.origin_input_ids) > self.max_req_input_len:
            logger.warning(
                "Request length is longer than the KV cache pool size or "
                "the max context length. Truncated!!!"
            )
            req.origin_input_ids = req.origin_input_ids[: self.max_req_input_len]

        req.sampling_params.max_new_tokens = min(
            (
                req.sampling_params.max_new_tokens
                if req.sampling_params.max_new_tokens is not None
                else 1 << 30
            ),
            self.max_req_len - len(req.origin_input_ids) - 1,
        )

        self.waiting_queue.append(req)

    def handle_embedding_request(
        self,
        recv_req: Union[TokenizedEmbeddingReqInput, TokenizedRewardReqInput],
    ):
        req = Req(
            recv_req.rid,
            recv_req.input_text,
            recv_req.input_ids,
            recv_req.sampling_params,
        )
        req.tokenizer = self.tokenizer

        # Truncate prompts that are too long
        if len(req.origin_input_ids) >= self.max_req_input_len:
            logger.warning(
                "Request length is longer than the KV cache pool size or "
                "the max context length. Truncated!!!"
            )
            req.origin_input_ids = req.origin_input_ids[: self.max_req_input_len]

        self.waiting_queue.append(req)

    def print_decode_stats(self):
        num_used = self.max_total_num_tokens - (
            self.token_to_kv_pool.available_size() + self.tree_cache.evictable_size()
        )
        throughput = self.num_generated_tokens / (time.time() - self.last_stats_tic)
        self.num_generated_tokens = 0
        self.last_stats_tic = time.time()
        num_running_reqs = len(self.running_batch.reqs) if self.running_batch else 0
        logger.info(
            f"Decode batch. "
            f"#running-req: {num_running_reqs}, "
            f"#token: {num_used}, "
            f"token usage: {num_used / self.max_total_num_tokens:.2f}, "
            f"gen throughput (token/s): {throughput:.2f}, "
            f"#queue-req: {len(self.waiting_queue)}"
        )

    def check_memory(self):
        available_size = (
            self.token_to_kv_pool.available_size() + self.tree_cache.evictable_size()
        )
        if available_size != self.max_total_num_tokens:
            warnings.warn(
                "Warning: "
                f"available_size={available_size}, max_total_num_tokens={self.max_total_num_tokens}\n"
                "KV cache pool leak detected!"
            )
            exit(1) if crash_on_warning else None

        if len(self.req_to_token_pool.free_slots) != self.req_to_token_pool.size:
            warnings.warn(
                "Warning: "
                f"available req slots={len(self.req_to_token_pool.free_slots)}, "
                f"total slots={self.req_to_token_pool.size}\n"
                "Memory pool leak detected!"
            )
            exit(1) if crash_on_warning else None

    def get_next_batch_to_run(self):
        # Merge the prefill batch into the running batch
        if (
            self.last_batch
            and not self.last_batch.forward_mode.is_decode()
            and not self.last_batch.is_empty()
        ):
            if self.being_chunked_req:
                self.last_batch.filter_batch(
                    being_chunked_req=self.being_chunked_req
                )
                self.tree_cache.cache_unfinished_req(self.being_chunked_req)
                # Inflight request keeps its rid but will get a new req_pool_idx.
                self.req_to_token_pool.free(self.being_chunked_req.req_pool_idx)
                self.batch_is_full = False
            if not self.last_batch.is_empty():
                if self.running_batch is None:
                    self.running_batch = self.last_batch
                else:
                    self.running_batch.merge_batch(self.last_batch)

        # Prefill first
        new_batch = self.get_new_batch_prefill()
        if new_batch is not None:
            return new_batch

        # Check memory
        if self.running_batch is None:
            return

        # Run decode
        before_bs = self.running_batch.batch_size()
        self.update_running_batch()
        if not self.running_batch:
            self.batch_is_full = False
            return None
        if before_bs != self.running_batch.batch_size():
            self.batch_is_full = False
        return self.running_batch

    def get_new_batch_prefill(self) -> Optional[ScheduleBatch]:
        # Handle the cases where prefill is not allowed
        if (
            self.batch_is_full or len(self.waiting_queue) == 0
        ) and self.being_chunked_req is None:
            return None

        running_bs = len(self.running_batch.reqs) if self.running_batch else 0
        if running_bs >= self.max_running_requests:
            self.batch_is_full = True
            return None

        # Get priority queue
        prefix_computed = self.policy.calc_priority(self.waiting_queue)

        # Prefill policy
        num_mixed_running = running_bs if self.is_mixed_chunk else 0
        adder = PrefillAdder(
            self.tree_cache,
            self.running_batch,
            self.new_token_ratio,
            self.token_to_kv_pool.available_size() + self.tree_cache.evictable_size(),
            self.max_prefill_tokens,
            self.chunked_prefill_size,
            num_mixed_running,
        )

        has_inflight = self.being_chunked_req is not None
        if has_inflight:
            self.being_chunked_req.init_next_round_input()
            self.being_chunked_req = adder.add_inflight_req(
                self.being_chunked_req
            )

        if self.lora_paths:
            lora_set = (
                set([req.lora_path for req in self.running_batch.reqs])
                if self.running_batch is not None
                else set([])
            )

        # Get requests from the waiting queue to a new prefill batch
        for req in self.waiting_queue:
            if (
                self.lora_paths
                and len(
                    lora_set
                    | set([req.lora_path for req in adder.can_run_list])
                    | set([req.lora_path])
                )
                > self.max_loras_per_batch
            ):
                self.batch_is_full = True
                break

            if running_bs + len(adder.can_run_list) >= self.max_running_requests:
                self.batch_is_full = True
                break

            req.init_next_round_input(None if prefix_computed else self.tree_cache)
            res = adder.add_one_req(req)
            if res != AddReqResult.CONTINUE:
                if res == AddReqResult.NO_TOKEN:
                    self.batch_is_full = True
                break

        # Update waiting queue
        can_run_list = adder.can_run_list
        if len(can_run_list) == 0:
            return None
        self.waiting_queue = [
            x for x in self.waiting_queue if x not in set(can_run_list)
        ]

        if adder.new_inflight_req is not None:
            assert self.being_chunked_req is None
            self.being_chunked_req = adder.new_inflight_req

        if self.being_chunked_req:
            self.being_chunked_req.is_being_chunked += 1

        # Print stats
        if self.tp_rank == 0:
            if isinstance(self.tree_cache, RadixCache):
                self.tree_cache_metrics["total"] += (
                    adder.log_input_tokens + adder.log_hit_tokens
                ) / 10**9
                self.tree_cache_metrics["hit"] += (adder.log_hit_tokens) / 10**9
                tree_cache_hit_rate = (
                    self.tree_cache_metrics["hit"] / self.tree_cache_metrics["total"]
                )
            else:
                tree_cache_hit_rate = 0.0

            num_used = self.max_total_num_tokens - (
                self.token_to_kv_pool.available_size()
                + self.tree_cache.evictable_size()
            )

            if num_mixed_running > 0:
                logger.info(
                    f"Prefill batch"
                    f"(mixed #running-req: {num_mixed_running}). "
                    f"#new-seq: {len(can_run_list)}, "
                    f"#new-token: {adder.log_input_tokens}, "
                    f"#cached-token: {adder.log_hit_tokens}, "
                    f"cache hit rate: {100.0 * tree_cache_hit_rate:.2f}%, "
                    f"token usage: {num_used / self.max_total_num_tokens:.2f}, "
                    f"#queue-req: {len(self.waiting_queue) + has_inflight}"
                )
            else:
                logger.info(
                    f"Prefill batch. "
                    f"#new-seq: {len(can_run_list)}, "
                    f"#new-token: {adder.log_input_tokens}, "
                    f"#cached-token: {adder.log_hit_tokens}, "
                    f"cache hit rate: {100.0 * tree_cache_hit_rate:.2f}%, "
                    f"token usage: {num_used / self.max_total_num_tokens:.2f}, "
                    f"#running-req: {running_bs}, "
                    f"#queue-req: {len(self.waiting_queue) + has_inflight}"
                )

        # Create a new batch
        new_batch = ScheduleBatch.init_new(
            can_run_list,
            self.req_to_token_pool,
            self.token_to_kv_pool,
            self.tree_cache,
            self.model_config,
        )
        new_batch.prepare_for_extend()

        # Mixed-style chunked prefill
        if self.is_mixed_chunk and self.running_batch is not None:
            self.running_batch.filter_batch()
            if not self.running_batch.is_empty():
                self.running_batch.prepare_for_decode(self.enable_overlap)
                new_batch.mix_with_running(self.running_batch)
                new_batch.decoding_reqs = self.running_batch.reqs
            self.running_batch = None
        else:
            new_batch.decoding_reqs = None

        return new_batch

    def update_running_batch(self):
        """Update the current running decoding batch."""
        global test_retract
        batch = self.running_batch

        batch.filter_batch()
        if batch.is_empty():
            self.running_batch = None
            return

        # Check if decode out of memory
        if not batch.check_decode_mem() or (test_retract and batch.batch_size() > 10):
            old_ratio = self.new_token_ratio

            retracted_reqs, new_token_ratio = batch.retract_decode()
            self.new_token_ratio = new_token_ratio

            logger.info(
                "Decode out of memory happened. "
                f"#retracted_reqs: {len(retracted_reqs)}, "
                f"#new_token_ratio: {old_ratio:.4f} -> {self.new_token_ratio:.4f}"
            )
            self.waiting_queue.extend(retracted_reqs)
        else:
            self.new_token_ratio = max(
                self.new_token_ratio - self.new_token_ratio_decay,
                self.min_new_token_ratio,
            )

        # Check for jump-forward
        if not self.disable_regex_jump_forward:
            jump_forward_reqs = batch.check_for_jump_forward(self.pad_input_ids_func)
            self.waiting_queue.extend(jump_forward_reqs)
            if batch.is_empty():
                self.running_batch = None
                return

        # Update batch tensors
        batch.prepare_for_decode(self.enable_overlap)

    def run_batch(self, batch: ScheduleBatch):
        """Run a batch."""
        self.forward_ct += 1

        if self.is_generation:
            if batch.forward_mode.is_decode() or batch.extend_num_tokens != 0:
                model_worker_batch = batch.get_model_worker_batch()
                logits_output, next_token_ids = self.tp_worker.forward_batch_generation(
                    model_worker_batch
                )
            else:
                logits_output = None
                if self.skip_tokenizer_init:
                    next_token_ids = torch.full(
                        (batch.batch_size(),), self.tokenizer.eos_token_id
                    )
                else:
                    next_token_ids = torch.full((batch.batch_size(),), 0)
            batch.output_ids = next_token_ids
            ret = logits_output, next_token_ids, model_worker_batch.bid
        else:  # embedding or reward model
            assert batch.extend_num_tokens != 0
            model_worker_batch = batch.get_model_worker_batch()
            embeddings = self.tp_worker.forward_batch_embedding(model_worker_batch)
            ret = embeddings, model_worker_batch.bid
        return ret

    def process_batch_result(self, batch: ScheduleBatch, result):
        if batch.forward_mode.is_decode():
            self.process_batch_result_decode(batch, result)
            if batch.is_empty():
                self.running_batch = None
        else:
            self.process_batch_result_prefill(batch, result)

    def process_batch_result_prefill(self, batch: ScheduleBatch, result):

        if self.is_generation:
            logits_output, next_token_ids, bid = result

            if self.enable_overlap:
                logits_output, next_token_ids = self.tp_worker.resulve_batch_result(bid)
            else:
                # Move next_token_ids and logprobs to cpu
                if batch.return_logprob:
                    logits_output.next_token_logprobs = (
                        logits_output.next_token_logprobs[
                            torch.arange(len(next_token_ids), device=self.device),
                            next_token_ids,
                        ].tolist()
                    )
                    logits_output.input_token_logprobs = (
                        logits_output.input_token_logprobs.tolist()
                    )
                    logits_output.normalized_prompt_logprobs = (
                        logits_output.normalized_prompt_logprobs.tolist()
                    )
                next_token_ids = next_token_ids.tolist()

            # Check finish conditions
            logprob_pt = 0
            for i, req in enumerate(batch.reqs):
                if req.is_being_chunked > 0:
                    req.is_being_chunked -= 1
                else:
                    # Inflight reqs' prefill is not finished
                    req.completion_tokens_wo_jump_forward += 1
                    req.output_ids.append(next_token_ids[i])
                    req.check_finished()

                    if req.finished():
                        self.tree_cache.cache_finished_req(req)
                    elif not batch.decoding_reqs or req not in batch.decoding_reqs:
                        self.tree_cache.cache_unfinished_req(req)

                    if req.grammar is not None:
                        req.grammar.accept_token(next_token_ids[i])

                    if req.return_logprob:
                        logprob_pt += self.add_logprob_return_values(
                            i, req, logprob_pt, next_token_ids, logits_output
                        )
        else:  # embedding or reward model
            embeddings, bid = result
            embeddings = embeddings.tolist()

            # Check finish conditions
            for i, req in enumerate(batch.reqs):
                req.embedding = embeddings[i]
                if req.is_being_chunked > 0:
                    req.is_being_chunked -= 1
                else:
                    # Inflight reqs' prefill is not finished
                    # dummy output token for embedding models
                    req.output_ids.append(0)
                    req.check_finished()

                if req.finished():
                    self.tree_cache.cache_finished_req(req)
                else:
                    self.tree_cache.cache_unfinished_req(req)

        self.stream_output(batch.reqs)

    def process_batch_result_decode(self, batch: ScheduleBatch, result):
        logits_output, next_token_ids, bid = result
        self.num_generated_tokens += len(batch.reqs)

        if self.enable_overlap:
            logits_output, next_token_ids = self.tp_worker.resulve_batch_result(bid)
            next_token_logprobs = logits_output.next_token_logprobs
        else:
            # Move next_token_ids and logprobs to cpu
            if batch.return_logprob:
                next_token_logprobs = logits_output.next_token_logprobs[
                    torch.arange(len(next_token_ids), device=self.device),
                    next_token_ids,
                ].tolist()
            next_token_ids = next_token_ids.tolist()

        self.token_to_kv_pool.free_group_begin()

        # Check finish condition
        for i, (req, next_token_id) in enumerate(zip(batch.reqs, next_token_ids)):
            if self.server_args.enable_overlap_schedule and req.finished():
                self.token_to_kv_pool.free(batch.out_cache_loc[i : i + 1])
                continue

            req.completion_tokens_wo_jump_forward += 1
            req.output_ids.append(next_token_id)
            req.check_finished()

            if req.grammar is not None:
                req.grammar.accept_token(next_token_id)

            if req.finished():
                self.tree_cache.cache_finished_req(req)

            if req.return_logprob:
                req.output_token_logprobs.append(
                    (next_token_logprobs[i], next_token_id)
                )
                if req.top_logprobs_num > 0:
                    req.output_top_logprobs.append(logits_output.output_top_logprobs[i])

        self.stream_output(batch.reqs)

        self.token_to_kv_pool.free_group_end()

        self.forward_ct_decode = (self.forward_ct_decode + 1) % (1 << 30)
        if self.tp_rank == 0 and self.forward_ct_decode % self.server_args.decode_log_interval == 0:
            self.print_decode_stats()

    def add_logprob_return_values(
        self,
        i: int,
        req: Req,
        pt: int,
        next_token_ids: List[int],
        output: LogitsProcessorOutput,
    ):
        """Attach logprobs to the return values."""
        req.output_token_logprobs.append(
            (output.next_token_logprobs[i], next_token_ids[i])
        )

        # If logprob_start_len > 0, then first logprob_start_len prompt tokens will be ignored.
        num_input_logprobs = req.extend_input_len - req.extend_logprob_start_len

        if req.normalized_prompt_logprob is None:
            req.normalized_prompt_logprob = output.normalized_prompt_logprobs[i]

        if req.input_token_logprobs is None:
            input_token_logprobs = output.input_token_logprobs[
                pt : pt + num_input_logprobs - 1 - req.last_update_decode_tokens
            ]
            input_token_ids = req.fill_ids[
                len(req.fill_ids)
                - num_input_logprobs
                + 1 : len(req.fill_ids)
                - req.last_update_decode_tokens
            ]
            req.input_token_logprobs = list(zip(input_token_logprobs, input_token_ids))

            if (
                req.logprob_start_len == 0
            ):  # The first token does not have logprob, pad it.
                req.input_token_logprobs = [
                    (None, req.fill_ids[0])
                ] + req.input_token_logprobs

        if req.last_update_decode_tokens != 0:
            # Some decode tokens are re-computed in an extend batch
            req.output_token_logprobs.extend(
                list(
                    zip(
                        output.input_token_logprobs[
                            pt
                            + num_input_logprobs
                            - 1
                            - req.last_update_decode_tokens : pt
                            + num_input_logprobs
                            - 1
                        ],
                        req.fill_ids[
                            len(req.fill_ids)
                            - req.last_update_decode_tokens : len(req.fill_ids)
                        ],
                    )
                )
            )

        if req.top_logprobs_num > 0:
            if req.input_top_logprobs is None:
                req.input_top_logprobs = output.input_top_logprobs[i]
                if req.logprob_start_len == 0:
                    req.input_top_logprobs = [None] + req.input_top_logprobs

            if req.last_update_decode_tokens != 0:
                req.output_top_logprobs.extend(
                    output.input_top_logprobs[i][-req.last_update_decode_tokens :]
                )
            req.output_top_logprobs.append(output.output_top_logprobs[i])

        return num_input_logprobs

    def stream_output(self, reqs: List[Req]):
        """Stream the output to detokenizer."""
        output_rids = []
        output_meta_info: List[dict] = []
        output_finished_reason: List[BaseFinishReason] = []
        if self.is_generation:
            output_vids = []
            decoded_texts = []
            output_read_ids = []
            output_read_offsets = []
            output_ids = []
            output_skip_special_tokens = []
            output_spaces_between_special_tokens = []
            output_no_stop_trim = []
        else:  # embedding or reward model
            output_embeddings = []

        is_stream_iter = self.forward_ct_decode % self.stream_interval == 0

        for req in reqs:
            if req.finished() or (
                req.stream and (is_stream_iter or len(req.output_ids) == 1)
            ):
                output_rids.append(req.rid)
                output_finished_reason.append(req.finished_reason)
                if self.is_generation:
                    output_vids.append(req.vid)
                    decoded_texts.append(req.decoded_text)
                    read_ids, read_offset = req.init_incremental_detokenize()
                    output_read_ids.append(read_ids)
                    output_read_offsets.append(read_offset)
                    if self.skip_tokenizer_init:
                        output_ids.append(req.output_ids)
                    output_skip_special_tokens.append(
                        req.sampling_params.skip_special_tokens
                    )
                    output_spaces_between_special_tokens.append(
                        req.sampling_params.spaces_between_special_tokens
                    )
                    output_no_stop_trim.append(req.sampling_params.no_stop_trim)

                    meta_info = {
                        "prompt_tokens": len(req.origin_input_ids),
                        "completion_tokens": len(req.output_ids),
                        "completion_tokens_wo_jump_forward": req.completion_tokens_wo_jump_forward,
                        "cached_tokens": req.cached_tokens,
                        "finish_reason": (
                            req.finished_reason.to_json()
                            if req.finished_reason is not None
                            else None
                        ),
                    }
                    if req.return_logprob:
                        (
                            meta_info["input_token_logprobs"],
                            meta_info["output_token_logprobs"],
                            meta_info["input_top_logprobs"],
                            meta_info["output_top_logprobs"],
                            meta_info["normalized_prompt_logprob"],
                        ) = (
                            req.input_token_logprobs,
                            req.output_token_logprobs,
                            req.input_top_logprobs,
                            req.output_top_logprobs,
                            req.normalized_prompt_logprob,
                        )
                    output_meta_info.append(meta_info)
                else:  # embedding or reward model
                    output_embeddings.append(req.embedding)
                    meta_info = {
                        "prompt_tokens": len(req.origin_input_ids),
                    }
                    output_meta_info.append(meta_info)

        # Send to detokenizer
        if output_rids:
            if self.is_generation:
                self.send_to_detokenizer.send_pyobj(
                    BatchTokenIDOut(
                        output_rids,
                        output_vids,
                        decoded_texts,
                        output_read_ids,
                        output_read_offsets,
                        output_ids,
                        output_skip_special_tokens,
                        output_spaces_between_special_tokens,
                        output_meta_info,
                        output_finished_reason,
                        output_no_stop_trim,
                    )
                )
            else:  # embedding or reward model
                self.send_to_detokenizer.send_pyobj(
                    BatchEmbeddingOut(
                        output_rids,
                        output_embeddings,
                        output_meta_info,
                        output_finished_reason,
                    )
                )

    def flush_cache(self):
        """Flush the memory pool and cache."""
        if len(self.waiting_queue) == 0 and (
            self.running_batch is None or len(self.running_batch.reqs) == 0
        ):
            self.tree_cache.reset()
            self.tree_cache_metrics = {"total": 0, "hit": 0}
            if self.grammar_cache is not None:
                self.grammar_cache.reset()
            # TODO(dark): reset the bnf cache
            self.req_to_token_pool.clear()
            self.token_to_kv_pool.clear()
            torch.cuda.empty_cache()
            logger.info("Cache flushed successfully!")
            if_success = True
        else:
            logging.warning(
                f"Cache not flushed because there are pending requests. "
                f"#queue-req: {len(self.waiting_queue)}, "
                f"#running-req: {0 if self.running_batch is None else len(self.running_batch.reqs)}"
            )
            if_success = False
        return if_success

    def abort_request(self, recv_req: AbortReq):
        # Delete requests in the waiting queue
        to_del = None
        for i, req in enumerate(self.waiting_queue):
            if req.rid == recv_req.rid:
                to_del = i
                break

        if to_del is not None:
            del self.waiting_queue[to_del]

        # Delete requests in the running batch
        if self.running_batch:
            for req in self.running_batch.reqs:
                if req.rid == recv_req.rid and not req.finished():
                    req.finished_reason = FINISH_ABORT()
                    self.tree_cache.cache_finished_req(req)
                    break

    def update_weights(self, recv_req: UpdateWeightReqInput):
        """In-place update of the weights."""
        success, message = self.tp_worker.update_weights(recv_req)
        if success:
            flash_cache_success = self.flush_cache()
            assert flash_cache_success, "Cache flush failed after updating weights"
        else:
            logger.error(message)
        return success, message

    def start_profile(self) -> None:
        if self.profiler is None:
            raise RuntimeError("Profiler is not enabled.")
        self.profiler.start()

    def stop_profile(self) -> None:
        if self.profiler is None:
            raise RuntimeError("Profiler is not enabled.")
        self.profiler.stop()
        self.profiler.export_chrome_trace(
            self.torch_profiler_trace_dir + "/" + str(time.time()) + ".trace.json.gz"
        )
        logger.info("Profiler is done")


def run_scheduler_process(
    server_args: ServerArgs,
    port_args: PortArgs,
    gpu_id: int,
    tp_rank: int,
    dp_rank: Optional[int],
    pipe_writer,
):
    if dp_rank is None:
        configure_logger(server_args, prefix=f" TP{tp_rank}")
    else:
        configure_logger(server_args, prefix=f" DP{dp_rank} TP{tp_rank}")

    suppress_other_loggers()

    try:
        scheduler = Scheduler(server_args, port_args, gpu_id, tp_rank, dp_rank)
        pipe_writer.send("ready")
        if server_args.enable_overlap_schedule:
            scheduler.event_loop_overlap()
        else:
            scheduler.event_loop_normal()
    except Exception:
        msg = get_exception_traceback()
        logger.error(msg)
        kill_parent_process()