[Feature] Support mamba radix cache v0 (#11214)

Co-authored-by: hanming-lu <hanming@x.ai>
Co-authored-by: hzh0425 <hzh0425@apache.org>
Co-authored-by: thalahors <ericalcaide1@gmail.com>

python/sglang/srt/managers/schedule_batch.py

@@ -65,7 +65,8 @@ from sglang.srt.mem_cache.common import (
     alloc_for_extend,
     alloc_token_slots,
 )
-from sglang.srt.mem_cache.memory_pool import ReqToTokenPool
+from sglang.srt.mem_cache.mamba_radix_cache import MambaRadixCache
+from sglang.srt.mem_cache.memory_pool import HybridReqToTokenPool, ReqToTokenPool
 from sglang.srt.mem_cache.radix_cache import RadixKey
 from sglang.srt.mem_cache.swa_radix_cache import SWARadixCache
 from sglang.srt.metrics.collector import SchedulerMetricsCollector, TimeStats
@@ -522,6 +523,7 @@ class Req:
 
         # Memory pool info
         self.req_pool_idx: Optional[int] = None
+        self.mamba_pool_idx: Optional[torch.Tensor] = None  # shape (1)
 
         # Check finish
         self.tokenizer = None
@@ -727,7 +729,12 @@ class Req:
                 self.last_host_node,
                 self.host_hit_length,
             ) = tree_cache.match_prefix(
-                key=RadixKey(token_ids=token_ids, extra_key=self.extra_key)
+                key=RadixKey(token_ids=token_ids, extra_key=self.extra_key),
+                **(
+                    {"req": self, "cow_mamba": True}
+                    if isinstance(tree_cache, MambaRadixCache)
+                    else {}
+                ),
             )
             self.last_matched_prefix_len = len(self.prefix_indices)
         self.extend_input_len = len(self.fill_ids) - len(self.prefix_indices)
@@ -877,6 +884,7 @@ class Req:
         self.extend_logprob_start_len = 0
         self.is_chunked = 0
         self.req_pool_idx = None
+        self.mamba_pool_idx = None
         self.already_computed = 0
 
     def offload_kv_cache(self, req_to_token_pool, token_to_kv_pool_allocator):
@@ -1071,6 +1079,27 @@ class ScheduleBatch(ScheduleBatchDisaggregationDecodeMixin):
     def is_empty(self):
         return len(self.reqs) == 0
 
+    def alloc_req_slots(self, num_reqs: int, reqs: Optional[List[Req]] = None):
+        if isinstance(self.req_to_token_pool, HybridReqToTokenPool):
+            mamba_available_size = self.req_to_token_pool.mamba_pool.available_size()
+            if mamba_available_size < num_reqs:
+                if self.tree_cache is not None and isinstance(
+                    self.tree_cache, MambaRadixCache
+                ):
+                    mamba_num = max(0, num_reqs - mamba_available_size)
+                    self.tree_cache.evict_mamba(mamba_num)
+            req_pool_indices = self.req_to_token_pool.alloc(num_reqs, reqs)
+        else:
+            req_pool_indices = self.req_to_token_pool.alloc(num_reqs)
+        if req_pool_indices is None:
+            raise RuntimeError(
+                "alloc_req_slots runs out of memory. "
+                "Please set a smaller number for `--max-running-requests`. "
+                f"{self.req_to_token_pool.available_size()=}, "
+                f"{num_reqs=}, "
+            )
+        return req_pool_indices
+
     def allocate_for_eagle_v2(self):
         from sglang.srt.speculative.eagle_info import EagleDraftInput
         from sglang.srt.speculative.spec_utils import assign_req_to_token_pool

python/sglang/srt/managers/schedule_policy.py

@@ -27,6 +27,7 @@ import torch
 from sglang.srt.managers.schedule_batch import Req, ScheduleBatch
 from sglang.srt.mem_cache.allocator import SWATokenToKVPoolAllocator
 from sglang.srt.mem_cache.base_prefix_cache import BasePrefixCache
+from sglang.srt.mem_cache.mamba_radix_cache import MambaRadixCache
 from sglang.srt.mem_cache.radix_cache import RadixCache, RadixKey, TreeNode
 from sglang.srt.server_args import ServerArgs
 
@@ -357,6 +358,7 @@ class PrefillAdder:
         self.is_hybrid = isinstance(
             self.token_to_kv_pool_allocator, SWATokenToKVPoolAllocator
         )
+        self.is_hybrid_gdn_cache = isinstance(self.tree_cache, MambaRadixCache)
 
         self.priority_scheduling_preemption_threshold = (
             priority_scheduling_preemption_threshold
@@ -380,6 +382,11 @@ class PrefillAdder:
                 self.token_to_kv_pool_allocator.swa_available_size()
                 + self.tree_cache.swa_evictable_size(),
             )
+        elif self.is_hybrid_gdn_cache:
+            available_and_evictable = (
+                self.token_to_kv_pool_allocator.available_size()
+                + self.tree_cache.full_evictable_size()
+            )
         else:
             available_and_evictable = (
                 self.token_to_kv_pool_allocator.available_size()
@@ -397,6 +404,11 @@ class PrefillAdder:
                 self.token_to_kv_pool_allocator.swa_available_size()
                 + self.tree_cache.swa_evictable_size(),
             )
+        elif self.is_hybrid_gdn_cache:
+            available_and_evictable = (
+                self.token_to_kv_pool_allocator.available_size()
+                + self.tree_cache.full_evictable_size()
+            )
         else:
             available_and_evictable = (
                 self.token_to_kv_pool_allocator.available_size()

python/sglang/srt/managers/scheduler.py

@@ -146,6 +146,7 @@ from sglang.srt.managers.session_controller import Session
 from sglang.srt.managers.utils import validate_input_length
 from sglang.srt.mem_cache.chunk_cache import ChunkCache, SWAChunkCache
 from sglang.srt.mem_cache.hiradix_cache import HiRadixCache
+from sglang.srt.mem_cache.mamba_radix_cache import MambaRadixCache
 from sglang.srt.mem_cache.radix_cache import RadixCache
 from sglang.srt.mem_cache.swa_radix_cache import SWARadixCache
 from sglang.srt.model_executor.forward_batch_info import ForwardBatch, PPProxyTensors
@@ -470,6 +471,10 @@ class Scheduler(
 
         # Hybrid memory pool
         self.is_hybrid = self.tp_worker.is_hybrid
+        self.is_hybrid_gdn = (
+            self.tp_worker.worker.model_runner.hybrid_gdn_config is not None
+        )
+
         if self.is_hybrid:
             self.sliding_window_size = self.tp_worker.sliding_window_size
             self.full_tokens_per_layer, self.swa_tokens_per_layer = (
@@ -816,6 +821,16 @@ class Scheduler(
                     disable=server_args.disable_radix_cache,
                     is_eagle=self.spec_algorithm.is_eagle(),
                 )
+            elif self.is_hybrid_gdn:
+                assert (
+                    self.server_args.disaggregation_mode == "null"
+                ), "Hybrid GDN mode does not support disaggregation yet"
+                self.tree_cache = MambaRadixCache(
+                    req_to_token_pool=self.req_to_token_pool,
+                    token_to_kv_pool_allocator=self.token_to_kv_pool_allocator,
+                    page_size=self.page_size,
+                    disable=server_args.disable_radix_cache,
+                )
             elif server_args.enable_lmcache:
                 from sglang.srt.mem_cache.storage.lmcache.lmc_radix_cache import (
                     LMCRadixCache,
@@ -1689,6 +1704,25 @@ class Scheduler(
                 f"{self.full_tokens_per_layer=}, {full_available_size=}, {full_evictable_size=}, {self.tree_cache.full_protected_size()=}\n"
                 f"{self.swa_tokens_per_layer=}, {swa_available_size=}, {swa_evictable_size=}, {self.tree_cache.swa_protected_size()=}\n"
             )
+        elif self.is_hybrid_gdn and isinstance(self.tree_cache, MambaRadixCache):
+            (
+                full_num_used,
+                mamba_num_used,
+                _,
+                _,
+                full_available_size,
+                full_evictable_size,
+                mamba_available_size,
+                mamba_evictable_size,
+            ) = self._get_mamba_token_info()
+            memory_leak = (
+                full_num_used != self.tree_cache.full_protected_size()
+                or mamba_num_used != self.tree_cache.mamba_protected_size()
+            )
+            token_msg = (
+                f"{full_available_size=}, {full_evictable_size=}, {self.token_to_kv_pool_allocator.size=}, {self.tree_cache.full_protected_size()=}\n"
+                f"{mamba_available_size=}, {mamba_evictable_size=}, {self.req_to_token_pool.mamba_pool.size=}, {self.tree_cache.mamba_protected_size()=}\n"
+            )
         else:
             _, _, available_size, evictable_size = self._get_token_info()
             protected_size = self.tree_cache.protected_size()
@@ -1739,6 +1773,17 @@ class Scheduler(
                 ) = self._get_swa_token_info()
                 num_used = max(full_num_used, swa_num_used)
                 token_usage = max(full_token_usage, swa_token_usage)
+            elif self.is_hybrid_gdn:
+                (
+                    num_used,
+                    _,
+                    token_usage,
+                    _,
+                    _,
+                    _,
+                    _,
+                    _,
+                ) = self._get_mamba_token_info()
             else:
                 num_used, token_usage, _, _ = self._get_token_info()
             num_running_reqs = len(self.running_batch.reqs)
@@ -1766,7 +1811,9 @@ class Scheduler(
         self._publish_kv_events()
 
     def check_tree_cache(self):
-        if self.is_hybrid and isinstance(self.tree_cache, SWARadixCache):
+        if (self.is_hybrid and isinstance(self.tree_cache, SWARadixCache)) or (
+            self.is_hybrid_gdn and isinstance(self.tree_cache, MambaRadixCache)
+        ):
             self.tree_cache.sanity_check()
 
     def _get_token_info(self):
@@ -1776,6 +1823,35 @@ class Scheduler(
         token_usage = num_used / self.max_total_num_tokens
         return num_used, token_usage, available_size, evictable_size
 
+    def _get_mamba_token_info(self):
+        is_radix_tree = isinstance(self.tree_cache, MambaRadixCache)
+        full_available_size = self.token_to_kv_pool_allocator.available_size()
+        full_evictable_size = (
+            self.tree_cache.full_evictable_size() if is_radix_tree else 0
+        )
+        mamba_available_size = self.req_to_token_pool.mamba_pool.available_size()
+        mamba_evictable_size = (
+            self.tree_cache.mamba_evictable_size() if is_radix_tree else 0
+        )
+        full_num_used = self.token_to_kv_pool_allocator.size - (
+            full_available_size + full_evictable_size
+        )
+        mamba_num_used = self.req_to_token_pool.mamba_pool.size - (
+            mamba_available_size + mamba_evictable_size
+        )
+        full_token_usage = full_num_used / self.token_to_kv_pool_allocator.size
+        mamba_usage = mamba_num_used / self.req_to_token_pool.mamba_pool.size
+        return (
+            full_num_used,
+            mamba_num_used,
+            full_token_usage,
+            mamba_usage,
+            full_available_size,
+            full_evictable_size,
+            mamba_available_size,
+            mamba_evictable_size,
+        )
+
     def _get_swa_token_info(self):
         full_available_size = self.token_to_kv_pool_allocator.full_available_size()
         full_evictable_size = self.tree_cache.full_evictable_size()

python/sglang/srt/managers/scheduler_metrics_mixin.py

@@ -104,6 +104,23 @@ class SchedulerMetricsMixin:
                 f"full token usage: {full_token_usage:.2f}, "
                 f"swa token usage: {swa_token_usage:.2f}, "
             )
+        elif self.is_hybrid_gdn:
+            (
+                full_num_used,
+                _,
+                full_token_usage,
+                mamba_usage,
+                _,
+                _,
+                _,
+                _,
+            ) = self._get_mamba_token_info()
+            num_used = full_num_used
+            token_usage = full_token_usage
+            token_usage_msg = (
+                f"full token usage: {full_token_usage:.2f}, "
+                f"mamba usage: {mamba_usage:.2f}, "
+            )
         else:
             num_used, token_usage, _, _ = self._get_token_info()
             token_usage_msg = f"token usage: {token_usage:.2f}, "
@@ -203,6 +220,25 @@ class SchedulerMetricsMixin:
                 f"#swa token: {swa_num_used}, "
                 f"swa token usage: {swa_token_usage:.2f}, "
             )
+        elif self.is_hybrid_gdn:
+            (
+                full_num_used,
+                mamba_used,
+                full_token_usage,
+                mamba_usage,
+                _,
+                _,
+                _,
+                _,
+            ) = self._get_mamba_token_info()
+            num_used = full_num_used
+            token_usage = full_token_usage
+            token_usage_msg = (
+                f"#full token: {full_num_used}, "
+                f"full token usage: {full_token_usage:.2f}, "
+                f"mamba num: {mamba_used}, "
+                f"mamba usage: {mamba_usage:.2f}, "
+            )
         else:
             num_used, token_usage, _, _ = self._get_token_info()
             token_usage_msg = f"#token: {num_used}, token usage: {token_usage:.2f}, "

python/sglang/srt/mem_cache/mamba_radix_cache.py

+from __future__ import annotations
+
+"""
+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.
+"""
+
+"""
+The radix tree data structure for managing the hybrid (full and Mamba) KV cache.
+"""
+
+import heapq
+import time
+from collections import defaultdict
+from functools import partial
+from typing import TYPE_CHECKING, List, Optional, Tuple
+
+import torch
+
+from sglang.srt.mem_cache.allocator import TokenToKVPoolAllocator
+from sglang.srt.mem_cache.base_prefix_cache import BasePrefixCache, MatchResult
+from sglang.srt.mem_cache.memory_pool import HybridReqToTokenPool
+from sglang.srt.mem_cache.radix_cache import (
+    RadixKey,
+    _key_match_page_size1,
+    _key_match_paged,
+    get_child_key,
+)
+
+if TYPE_CHECKING:
+    from sglang.srt.managers.schedule_batch import Req
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class TreeNode:
+
+    counter = 0
+
+    def __init__(self, id: Optional[int] = None):
+        self.children = defaultdict(TreeNode)
+        self.parent: TreeNode = None
+        self.key: RadixKey = None
+        self.value: Optional[torch.Tensor] = None
+        self.mamba_value: Optional[torch.Tensor] = None
+        # invariant: for any node, if mamba_lock_ref is locked, full_lock_ref must be locked;
+        # if full_lock_ref is locked, mamba_lock_ref doesn't need to be locked. So,
+        # full_lock_ref is always >= mamba_lock_ref.
+        # for full_lock, once it is locked, its parent must be locked as well
+        # for mamba_lock, it only need lock node itself
+        self.full_lock_ref = 0
+        self.mamba_lock_ref = 0
+        # last access time is only used for sanity check. LRU is maintained by the lru list.
+        self.last_access_time = time.monotonic()
+
+        self.hit_count = 0
+        # store the host indices of KV cache
+        self.host_value = None
+
+        # for lru list, invariant:
+        # 1. prev has greater last_access_time
+        # 2. next has smaller last_access_time
+        self.prev = None
+        self.next = None
+        self.mamba_prev = None
+        self.mamba_next = None
+
+        self.id = TreeNode.counter if id is None else id
+        TreeNode.counter += 1
+
+    @property
+    def evicted(self):
+        return self.value is None
+
+    @property
+    def backuped(self):
+        return self.host_value is not None
+
+    def __lt__(self, other: "TreeNode"):
+        return self.last_access_time < other.last_access_time
+
+
+class LRUList:
+    def __init__(self, mamba: bool = False):
+        self.mamba = mamba
+        if self.mamba:
+            self.prv = "mamba_prev"
+            self.nxt = "mamba_next"
+            self.lock_ref = "mamba_lock_ref"
+        else:
+            self.prv = "prev"
+            self.nxt = "next"
+            self.lock_ref = "full_lock_ref"
+        # Initialize dummy head and tail nodes
+        self.head = TreeNode()  # Most recently used side
+        self.tail = TreeNode()  # Least recently used side
+        setattr(self.head, self.nxt, self.tail)  # self.head.next = self.tail
+        setattr(self.tail, self.prv, self.head)  # self.tail.prev = self.head
+        self.cache = {}
+
+    def _add_node(self, node):
+        """Helper to add node right after head (most recently used)"""
+        self._add_node_after(self.head, node)
+
+    def _add_node_after(self, old_node, new_node):
+        """Helper to add node right after old_node"""
+        setattr(new_node, self.prv, old_node)  # new_node.prev = old_node
+        setattr(
+            new_node, self.nxt, getattr(old_node, self.nxt)
+        )  # new_node.next = old_node.next
+        setattr(
+            getattr(old_node, self.nxt), self.prv, new_node
+        )  # old_node.next.prev = new_node
+        setattr(old_node, self.nxt, new_node)  # old_node.next = new_node
+
+    def _remove_node(self, node):
+        """Helper to remove node from linked list"""
+        setattr(
+            getattr(node, self.prv), self.nxt, getattr(node, self.nxt)
+        )  # node.prev.next = node.next
+        setattr(
+            getattr(node, self.nxt), self.prv, getattr(node, self.prv)
+        )  # node.next.prev = node.prev
+
+    def _get_lru(self) -> Optional[TreeNode]:
+        """
+        Get the least recently used node
+        """
+        if len(self.cache) == 0:
+            return None
+        return getattr(self.tail, self.prv)
+
+    def reset_node_mru(self, node):
+        """
+        Move a (existing) node to most recently used position
+        """
+        assert node.id in self.cache, f"Resetting node {node.id=} not in lru list"
+        assert (
+            not self.mamba or node.mamba_value is not None
+        ), f"Resetting mamba tombstone node in mamba lru list: {node.id=}"
+        self._remove_node(node)
+        self._add_node(node)
+
+    def reset_node_and_parents_mru(self, node, root_node):
+        """
+        Move an (existing) node and its parents to most recently used position. Child node is
+        more recently used than parent node.
+        """
+        prev_node = self.head
+        while node != root_node:
+            if not self.mamba or node.mamba_value is not None:
+                assert (
+                    node.id in self.cache
+                ), f"Resetting node {node.id=} not in lru list when resetting node and parents mru"
+                self._remove_node(node)
+                self._add_node_after(prev_node, node)
+                prev_node = node
+            node = node.parent
+
+    def insert_mru(self, node):
+        """
+        Insert a (new) node as most recently used
+        """
+        assert (
+            not self.mamba or node.mamba_value is not None
+        ), f"Inserting mamba tombstone node in mamba lru list: {node.id=}"
+        assert (
+            node.id not in self.cache
+        ), f"Inserting node {node.id=} already in lru list, existing node: {self.cache[node.id].id=}"
+        self.cache[node.id] = node
+        self._add_node(node)
+
+    def remove_node(self, node: TreeNode):
+        """
+        Remove node from lru list
+        """
+        assert node.id in self.cache, f"Removing node {node.id=} not in lru list"
+        assert (
+            not self.mamba or node.mamba_value is not None
+        ), f"Removing mamba tombstone node from mamba lru list: {node.id=}"
+        del self.cache[node.id]
+        self._remove_node(node)
+
+    def get_lru_no_lock(self) -> Optional[TreeNode]:
+        """
+        Get the least recently used node that is not locked
+        """
+        return self.get_prev_no_lock(self.tail, check_id=False)
+
+    def get_leaf_lru_no_lock(self) -> Optional[TreeNode]:
+        """
+        Get the least recently used leaf node that is not locked
+        """
+        return self.get_prev_leaf_no_lock(self.tail, check_id=False)
+
+    def get_prev_no_lock(
+        self, node: TreeNode, check_id: bool = True
+    ) -> Optional[TreeNode]:
+        """
+        Get the previous (i.e. more recently used) node that is not locked
+        """
+        if check_id:
+            assert (
+                node.id in self.cache
+            ), f"Getting prev of node {node.id=} not in lru list"
+        x = getattr(node, self.prv)  # x = node.prev
+        while getattr(x, self.lock_ref) > 0:
+            x = getattr(x, self.prv)  # x = x.prev
+        # if x is the head, it means there is no node in the lru list without lock
+        if x == self.head:
+            return None
+        return x
+
+    def get_prev_leaf_no_lock(self, node: TreeNode, check_id: bool = True):
+        """
+        Get the previous (i.e. more recently used) leaf node that is not locked
+        """
+        if check_id:
+            assert (
+                node.id in self.cache
+            ), f"Getting prev of node {node.id=} not in lru list"
+        x = getattr(node, self.prv)  # x = node.prev
+        while getattr(x, self.lock_ref) > 0 or len(x.children) > 0:
+            x = getattr(x, self.prv)  # x = x.prev
+        # if x is the head, it means there is no leaf node in the lru list without lock
+        if x == self.head:
+            return None
+        return x
+
+    def in_list(self, node: Optional[TreeNode]):
+        """
+        Check if the node is in the lru list
+        """
+        if not node:
+            return False
+        return node.id in self.cache
+
+    # Note: this is expensive, only use for debug
+    def sanity_check_evictable_size(self):
+        """
+        Check the evictable size (i.e. the size of the nodes that are not locked)
+        """
+        node = self.get_lru_no_lock()
+        evictable_size = 0
+        while self.in_list(node):
+            evictable_size += (
+                len(node.value) if not self.mamba else len(node.mamba_value)
+            )
+            node = self.get_prev_no_lock(node)
+        return evictable_size
+
+    # Note: this is expensive, only use for debug or idle check
+    def sanity_check(self, tree_cache: "MambaRadixCache"):
+        """
+        Check if the lru list is valid by rebuilding the lru list from the tree, heapifying it, and
+        checking if the lru list is valid.
+        """
+        try:
+            if self.mamba:
+                nodes = tree_cache._collect_nontombstone_nodes()
+            else:
+                nodes = tree_cache._collect_all_nodes()
+            total_nodes = len(nodes)
+            total_lru = len(self.cache)
+            # heapify based on last_access_time
+            heapq.heapify(nodes)
+            # the root node is not in the lru list
+            assert len(nodes) == (
+                total_lru + (0 if self.mamba else 1)
+            ), f"len(nodes): {len(nodes)}, total_lru: {total_lru}"
+
+            x_lru = self._get_lru()
+            while len(nodes):
+                x = heapq.heappop(nodes)
+                if x == tree_cache.root_node:
+                    # root node is not in the lru list
+                    continue
+                assert (
+                    x == x_lru
+                ), f"Incorrect LRU list, {self.mamba=}, x: {x.id=} != x_lru: {x_lru.id=}"
+                assert (
+                    x_lru.full_lock_ref == 0
+                ), f"x_lru should not be locked when idle, {x_lru.full_lock_ref=}, {x_lru.id=}"
+                assert (
+                    x_lru.mamba_lock_ref == 0
+                ), f"x_lru should not be locked when idle, {x_lru.mamba_lock_ref=}, {x_lru.id=}"
+                x_lru = getattr(x, self.prv)
+
+            if self.mamba:
+                evictable_size = tree_cache.mamba_evictable_size()
+                lru_list_evictable_size = tree_cache.mamba_lru_list_evictable_size()
+            else:
+                evictable_size = tree_cache.full_evictable_size()
+                lru_list_evictable_size = tree_cache.full_lru_list_evictable_size()
+
+            assert (
+                evictable_size == lru_list_evictable_size
+            ), f"{self.mamba=}, total nodes: {total_nodes}, total lru: {total_lru}, evictable size: {evictable_size} != lru list evictable size: {lru_list_evictable_size}"
+        except Exception as e:
+            msg = f"Mamba Radix tree sanity check failed, ping @yizhang2077: {e}"
+            logger.error(msg)
+            raise Exception(msg)
+
+
+class MambaRadixCache(BasePrefixCache):
+    def __init__(
+        self,
+        req_to_token_pool: HybridReqToTokenPool,
+        token_to_kv_pool_allocator: TokenToKVPoolAllocator,
+        page_size: int,
+        disable: bool = False,
+    ):
+        assert isinstance(token_to_kv_pool_allocator, TokenToKVPoolAllocator)
+        self.req_to_token_pool = req_to_token_pool
+        self.token_to_kv_pool_allocator = token_to_kv_pool_allocator
+
+        assert page_size == 1, "Only support page_size=1 in mamba radix cache now."
+        self.page_size = page_size
+        self.disable = disable
+
+        if self.token_to_kv_pool_allocator:
+            self.device = self.token_to_kv_pool_allocator.device
+        else:
+            self.device = torch.device("cpu")
+
+        self.key_match_fn = _key_match_page_size1
+        self.get_child_key_fn = get_child_key
+        self.reset()
+
+    ##### Public API #####
+
+    def reset(self) -> None:
+        self.root_node = TreeNode()
+        self.root_node.key = []
+        self.root_node.value = []
+        self.root_node.full_lock_ref = 1
+        self.root_node.mamba_lock_ref = 1
+        self.full_evictable_size_ = 0
+        self.mamba_evictable_size_ = 0
+        self.full_protected_size_ = 0
+        self.mamba_protected_size_ = 0
+        # LRU lists are used to maintain the order of eviction of the nodes in the tree
+        self.full_lru_list = LRUList(mamba=False)
+        self.mamba_lru_list = LRUList(mamba=True)
+
+    def match_prefix(self, key: RadixKey, **kwargs) -> MatchResult:
+        """Find the matching prefix from the radix tree.
+        Args:
+            key: A RadixKey contains token IDs to find a matching prefix.
+        Returns:
+            A tuple of a tensor of matching prefix token IDs and
+            the last node that contains the prefix values. Note that
+            this API can modify the internal state of the Radix tree.
+            The last node create a new child if the prefix is shorter
+            than the last node's value.
+        """
+        cow_mamba: bool = kwargs.get("cow_mamba", False)
+        req: Req = kwargs.get("req", None)
+
+        if self.disable or len(key) == 0:
+            return MatchResult(
+                device_indices=torch.empty(
+                    (0,),
+                    dtype=torch.int64,
+                    device=self.device,
+                ),
+                last_device_node=self.root_node,
+                last_host_node=self.root_node,
+            )
+
+        value, last_node = self._match_prefix_helper(key)
+
+        # copy mamba state to req local space if cow is true
+        if cow_mamba and last_node.mamba_value is not None:
+            assert req.req_pool_idx is None  # req_pool_idx is uninitialed
+
+            # for reqs without mamba cache
+            if req.mamba_pool_idx is None:
+                dst_index = self.req_to_token_pool.mamba_pool.alloc(1)
+                # try to alloc again, protect last_node from eviction
+                if dst_index is None:
+                    self.inc_lock_ref(last_node)
+                    self.evict_mamba(1)
+                    dst_index = self.req_to_token_pool.mamba_pool.alloc(1)
+                    self.dec_lock_ref(last_node)
+                    assert dst_index is not None, "Can not alloc mamba cache"
+                src_index = last_node.mamba_value
+                self.req_to_token_pool.mamba_pool.copy_from(src_index, dst_index)
+                req.mamba_pool_idx = dst_index[0]
+            else:
+                src_index = last_node.mamba_value
+                dst_index = req.mamba_pool_idx.unsqueeze(0)
+                self.req_to_token_pool.mamba_pool.copy_from(src_index, dst_index)
+
+        if value:
+            value = torch.cat(value)
+        else:
+            value = torch.empty((0,), dtype=torch.int64, device=self.device)
+
+        return MatchResult(
+            device_indices=value,
+            last_device_node=last_node,
+            last_host_node=last_node,
+        )
+
+    def insert(self, key: RadixKey, value=None, mamba_value=None) -> Tuple[int, bool]:
+        if self.disable:
+            return 0
+
+        if value is None:
+            value = torch.tensor([x for x in key.token_ids], dtype=torch.int64)
+        return self._insert_helper(self.root_node, key, value, mamba_value)
+
+    def cache_finished_req(self, req: Req) -> None:
+        """Cache request when it finishes."""
+        if self.disable:
+            kv_indices = self.req_to_token_pool.req_to_token[
+                req.req_pool_idx,
+                : len(req.origin_input_ids) + max(len(req.output_ids) - 1, 0),
+            ]
+            self.token_to_kv_pool_allocator.free(kv_indices)
+            self.req_to_token_pool.free(req.req_pool_idx)
+            return
+
+        token_ids = (req.origin_input_ids + req.output_ids)[:-1]
+        kv_indices = self.req_to_token_pool.req_to_token[
+            req.req_pool_idx, : len(token_ids)
+        ]
+
+        page_aligned_len = len(kv_indices)
+        page_aligned_kv_indices = kv_indices.to(dtype=torch.int64, copy=True)
+
+        # Radix Cache takes one ref in memory pool
+        # insert the token_ids and kv_indices into the radix tree
+        # Note: the insert function already frees the overlapped kv_indices
+        mamba_value = (
+            self.req_to_token_pool.get_mamba_indices(req.req_pool_idx)
+            .unsqueeze(-1)
+            .clone()
+        )
+
+        new_prefix_len, mamba_exist = self.insert(
+            RadixKey(token_ids[:page_aligned_len], req.extra_key),
+            page_aligned_kv_indices,
+            mamba_value,
+        )
+
+        self.token_to_kv_pool_allocator.free(
+            kv_indices[len(req.prefix_indices) : new_prefix_len]
+        )
+
+        self.req_to_token_pool.free(req.req_pool_idx, free_mamba_cache=mamba_exist)
+        self.dec_lock_ref(req.last_node)
+
+    def cache_unfinished_req(self, req: Req, chunked=False) -> None:
+        """Cache request when it is unfinished."""
+        if self.disable:
+            kv_indices = self.req_to_token_pool.req_to_token[
+                req.req_pool_idx, : len(req.fill_ids)
+            ]
+            # `req.prefix_indices` will be used in `PrefillAdder::add_chunked_req` later
+            req.prefix_indices = kv_indices
+            return
+
+        token_ids = req.fill_ids
+        kv_indices = self.req_to_token_pool.req_to_token[
+            req.req_pool_idx, : len(token_ids)
+        ]
+        page_aligned_len = len(kv_indices)
+        page_aligned_kv_indices = kv_indices.to(dtype=torch.int64, copy=True)
+        page_aligned_token_ids = token_ids[:page_aligned_len]
+
+        mamba_value = self.req_to_token_pool.get_mamba_indices(
+            req.req_pool_idx
+        ).unsqueeze(-1)
+        # radix tree mamba value is forked from req space
+        mamba_value_forked = self.req_to_token_pool.mamba_pool.fork_from(mamba_value)
+
+        # if alloc mamba cache failed, do evict and alloc again
+        if mamba_value_forked is None:
+            self.evict_mamba(1)
+            mamba_value_forked = self.req_to_token_pool.mamba_pool.fork_from(
+                mamba_value
+            )
+            assert mamba_value_forked is not None, "Can not alloc mamba cache"
+        new_prefix_len, mamba_exist = self.insert(
+            RadixKey(page_aligned_token_ids, req.extra_key),
+            page_aligned_kv_indices,
+            mamba_value_forked,
+        )
+        self.token_to_kv_pool_allocator.free(
+            kv_indices[len(req.prefix_indices) : new_prefix_len]
+        )
+        # there is a mamba cache in radix cache, release it
+        if mamba_exist:
+            self.req_to_token_pool.mamba_pool.free(mamba_value_forked)
+
+        # The prefix indices could be updated, reuse it
+        new_indices, new_last_node, _, _ = self.match_prefix(
+            RadixKey(page_aligned_token_ids, req.extra_key)
+        )
+
+        if not mamba_exist:
+            assert torch.equal(new_last_node.mamba_value, mamba_value_forked)
+
+        assert len(req.prefix_indices) <= len(
+            new_indices
+        ), f"{req.prefix_indices=}, {new_indices=}"
+        assert new_prefix_len <= len(new_indices), f"{new_prefix_len=}, {new_indices=}"
+
+        self.req_to_token_pool.write(
+            (req.req_pool_idx, slice(len(req.prefix_indices), len(new_indices))),
+            new_indices[len(req.prefix_indices) :],
+        )
+
+        self.dec_lock_ref(req.last_node)
+        self.inc_lock_ref(new_last_node)
+
+        # `req.prefix_indices` will be used in `PrefillAdder::add_chunked_req` later
+        req.prefix_indices = new_indices
+        req.last_node = new_last_node
+
+    def pretty_print(self) -> None:
+        self._print_helper(self.root_node, 0)
+        total_size, total_mamba_size = self._total_size_helper()
+        print(f"#full_tokens: {total_size}, #mamba_num: {total_mamba_size}")
+
+    def total_size(self) -> Tuple[int, int]:
+        return self._total_size_helper()
+
+    def _evict_leaf_node(
+        self, x: TreeNode, is_evict_mamba: bool
+    ) -> Tuple[int, int, TreeNode, TreeNode]:
+        assert (
+            x.full_lock_ref == 0 and x.mamba_lock_ref == 0
+        ), f"evict leaf node invalid with {x.id=} {x.full_lock_ref=} {x.mamba_lock_ref=}"
+
+        assert x.mamba_value is not None, f"leaf node mamba value is not None, {x.id=}"
+        # 1. a leaf node, free full tokens and mamba
+        self.token_to_kv_pool_allocator.free(x.value)
+        full_num_evicted = len(x.value)
+        self.req_to_token_pool.mamba_pool.free(x.mamba_value)
+        mamba_num_evicted = len(x.mamba_value)
+
+        # 2. get the next node, update the lru lists
+        if is_evict_mamba:
+            x_next = self.mamba_lru_list.get_prev_no_lock(x)
+        else:
+            x_next = self.full_lru_list.get_prev_leaf_no_lock(x)
+        self.full_lru_list.remove_node(x)
+        self.mamba_lru_list.remove_node(x)
+
+        # 3. delete the leaf node
+        self._delete_leaf(x)
+
+        # 4. Iteratively delete tombstone leaves to maintain invariant that leaf nodes are not tombstone
+        x, leaf_full_num_evicted = self._iteratively_delete_tombstone_leaf(x)
+        full_num_evicted += leaf_full_num_evicted
+        return full_num_evicted, mamba_num_evicted, x, x_next
+
+    def evict_mamba(self, mamba_num: int) -> None:
+        if self.disable or mamba_num <= 0:
+            return
+        # get the least recently used node that is not locked, doesn't have to be a leaf
+        x = self.mamba_lru_list.get_lru_no_lock()
+        mamba_num_evicted = 0
+        # evict lru leaf nodes until mamba_num_tokens is reached
+        while mamba_num_evicted < mamba_num and (self.mamba_lru_list.in_list(x)):
+            assert x.mamba_value is not None, f"node has no mamba value, {x.id=}"
+            assert (
+                len(x.mamba_value) == 1
+            ), f"node has abnormal mamba length, {x.id=}, {len(x.mamba_value)=}"
+            assert x != self.root_node, f"root node is not evictable, {x.id=}"
+            assert x.mamba_lock_ref == 0, f"node is in use by mamba kv indices, {x.id=}"
+
+            if len(x.children) > 0:
+                # 1. an internal node, free mamba tokens.
+                self.req_to_token_pool.mamba_pool.free(x.mamba_value)
+                mamba_num_evicted += len(x.mamba_value)
+
+                # 2. get the next node, update the lru lists
+                x_next = self.mamba_lru_list.get_prev_no_lock(x)
+                self.mamba_lru_list.remove_node(x)
+
+                # 3. tombstone the node
+                self._tombstone_internal_node(x)
+            else:
+                _, mamba_evicted_delta, _, x_next = self._evict_leaf_node(x, True)
+                mamba_num_evicted += mamba_evicted_delta
+
+            x = x_next
+
+    def evict(self, full_num_tokens: int) -> None:
+        if self.disable or full_num_tokens <= 0:
+            return
+
+        full_num_evicted = 0
+        # get the least recently used leaf node that is not locked
+        x = self.full_lru_list.get_leaf_lru_no_lock()
+
+        while full_num_evicted < full_num_tokens and self.full_lru_list.in_list(x):
+            assert (
+                x != self.root_node
+            ), f"root node should not exist in full lru list, {x.id=}"
+            full_num_evicted_delta, _, x, x_next = self._evict_leaf_node(x, False)
+            full_num_evicted += full_num_evicted_delta
+
+            # if parent has no more children, it is a leaf. It is possible that this node is lru, so
+            # we need to get the first leaf node in the lru list
+            if len(x.parent.children) == 0:
+                x_next = self.full_lru_list.get_leaf_lru_no_lock()
+
+            x = x_next
+
+    def inc_lock_ref(self, node: TreeNode) -> Optional[int]:
+        """
+        Increment the lock reference count for the node.
+        It locks the full_lock_ref for nodes between the [last node, root), exclusive.
+        It locks the mamba_lock_ref for current node if its mamba_value exists.
+        """
+        if self.disable:
+            return None
+
+        # protect mamba value in current node if it exists
+        if node.mamba_value is not None:
+            if node.mamba_lock_ref == 0:
+                self.mamba_evictable_size_ -= len(node.mamba_value)
+                self.mamba_protected_size_ += len(node.mamba_value)
+            node.mamba_lock_ref += 1
+
+        while node != self.root_node:
+            # lock full from node to root
+            assert (
+                node.full_lock_ref >= 0
+            ), f"inc_lock_ref on node with {node.full_lock_ref=}, {node.id=}"
+            if node.full_lock_ref == 0:
+                self.full_evictable_size_ -= len(node.value)
+                self.full_protected_size_ += len(node.value)
+            node.full_lock_ref += 1
+            node = node.parent
+        return None
+
+    def dec_lock_ref(self, node: TreeNode):
+        """
+        Decrement the lock reference count for the node.
+        It unlocks the full_lock_ref for nodes between the [last node, root), exclusive.
+        It unlocks the mamba_lock_ref for current node if its mamba_value exists.
+        """
+        if self.disable:
+            return
+
+        if node.mamba_value is not None:
+            assert (
+                node.mamba_lock_ref > 0
+            ), f"dec_lock_ref on node with {node.mamba_lock_ref=}, {node.id=}"
+            if node.mamba_lock_ref == 1:
+                self.mamba_evictable_size_ += len(node.mamba_value)
+                self.mamba_protected_size_ -= len(node.mamba_value)
+            node.mamba_lock_ref -= 1
+
+        while node != self.root_node:
+            assert (
+                node.full_lock_ref > 0
+            ), f"dec_lock_ref on node with {node.full_lock_ref=}, {node.id=}"
+            if node.full_lock_ref == 1:
+                self.full_evictable_size_ += len(node.value)
+                self.full_protected_size_ -= len(node.value)
+            node.full_lock_ref -= 1
+            node = node.parent
+
+    def sanity_check(self):
+        self.full_lru_list.sanity_check(self)
+        self.mamba_lru_list.sanity_check(self)
+
+    def evictable_size(self) -> Tuple[int, int]:
+        # Note: use full_evictable_size() and mamba_evictable_size() instead.
+        raise NotImplementedError
+
+    def full_evictable_size(self) -> int:
+        return self.full_evictable_size_
+
+    def mamba_evictable_size(self) -> int:
+        return self.mamba_evictable_size_
+
+    # Note: this is expensive, only use for debug
+    def full_lru_list_evictable_size(self) -> int:
+        return self.full_lru_list.sanity_check_evictable_size()
+
+    # Note: this is expensive, only use for debug
+    def mamba_lru_list_evictable_size(self) -> int:
+        return self.mamba_lru_list.sanity_check_evictable_size()
+
+    def protected_size(self) -> Tuple[int, int]:
+        # Note: use full_protected_size() and mamba_protected_size() instead.
+        raise NotImplementedError
+
+    def full_protected_size(self) -> int:
+        # protected size refers to the size of the full cache that is locked
+        return self.full_protected_size_
+
+    def mamba_protected_size(self) -> int:
+        # protected size refers to the size of the mamba cache that is locked
+        return self.mamba_protected_size_
+
+    def all_values_flatten(self) -> torch.Tensor:
+        values = []
+
+        def _dfs_helper(node: TreeNode):
+            for _, child in node.children.items():
+                values.append(child.value)
+                _dfs_helper(child)
+
+        _dfs_helper(self.root_node)
+        return torch.cat(values)
+
+    ##### Internal Helper Functions #####
+
+    def _match_prefix_helper(
+        self, key: RadixKey
+    ) -> Tuple[List[torch.Tensor], TreeNode]:
+        """
+        Mamba prefix matching helper. It factors in the sliding window size such that
+        the matched node is guaranteed to either 1. connected to root without mamba tombstone,
+        or 2. the number of matching tokens from the matched node to the last mamba tombstone
+        node is greater than or equal to the sliding window size.
+        """
+        node = self.root_node
+        child_key = self.get_child_key_fn(key)
+
+        value = []
+        best_value_len = 0
+        best_last_node = node
+        while len(key) > 0 and child_key in node.children.keys():
+            child = node.children[child_key]
+            # update best_value_len and best_last_node if needed
+            if node.mamba_value is not None:
+                best_value_len = len(value)
+                best_last_node = node
+
+            prefix_len = self.key_match_fn(child.key, key)
+            if prefix_len < len(child.key):
+                new_node = self._split_node(child.key, child, prefix_len)
+                value.append(new_node.value)
+                node = new_node
+                break
+            else:
+                value.append(child.value)
+                node = child
+                key = key[prefix_len:]
+
+                if len(key):
+                    child_key = self.get_child_key_fn(key)
+        # handle best_value_len and best_last_node, for the case that last node is fully matched
+        if node.mamba_value is not None:
+            best_value_len = len(value)
+            best_last_node = node
+
+        # update time for matched nodes, and make nodes closer to root to be least recently used
+        # this allows mamba to evict nodes closer to root first
+        self.full_lru_list.reset_node_and_parents_mru(best_last_node, self.root_node)
+        self.mamba_lru_list.reset_node_and_parents_mru(best_last_node, self.root_node)
+
+        # This last_access_time is for sanity check, can be deleted after validation in production
+        cur_time = time.monotonic()
+        while node:
+            node.last_access_time = cur_time
+            cur_time -= 0.0001
+            node = node.parent
+
+        return value[:best_value_len], best_last_node
+
+    def _split_node(self, key: RadixKey, child: TreeNode, split_len: int) -> TreeNode:
+        # new_node -> child
+        new_node = TreeNode()
+        new_node.children = {self.get_child_key_fn(key[split_len:]): child}
+        new_node.parent = child.parent
+        new_node.mamba_value = None  # mamba cache can not be split
+        new_node.full_lock_ref = child.full_lock_ref
+        new_node.mamba_lock_ref = 0
+        new_node.key = child.key[:split_len]
+        new_node.value = child.value[:split_len]
+
+        # child time should be later than parent's time for mamba tombstone
+        child.last_access_time = time.monotonic()
+
+        self.full_lru_list.remove_node(child)
+        if child.mamba_value is not None:
+            self.mamba_lru_list.remove_node(child)
+        child.parent = new_node
+        child.key = child.key[split_len:]
+        child.value = child.value[split_len:]
+        new_node.parent.children[self.get_child_key_fn(key)] = new_node
+
+        # insert the new node and child into the lru lists, insert
+        # parent first so that parent is after child in the lru list
+        self.full_lru_list.insert_mru(new_node)
+        self.full_lru_list.insert_mru(child)
+        if child.mamba_value is not None:
+            self.mamba_lru_list.insert_mru(child)
+        return new_node
+
+    def _insert_helper(
+        self,
+        node: TreeNode,
+        key: RadixKey,
+        value,
+        mamba_value,
+    ) -> Tuple[int, bool]:
+        # Update the last access time from root to leaf, so that
+        # mamba will tombstone the node closer to root first
+        assert mamba_value is not None, "Mamba value should not be None here."
+        node.last_access_time = time.monotonic()
+        if node != self.root_node:
+            self.full_lru_list.reset_node_mru(node)
+            if node.mamba_value is not None:
+                self.mamba_lru_list.reset_node_mru(node)
+        if len(key) == 0:
+            return 0, True
+
+        child_key = self.get_child_key_fn(key)
+
+        total_prefix_length = 0
+        while len(key) > 0 and child_key in node.children.keys():
+            node = node.children[child_key]
+            node.last_access_time = time.monotonic()
+            self.full_lru_list.reset_node_mru(node)
+            if node.mamba_value is not None:
+                self.mamba_lru_list.reset_node_mru(node)
+            prefix_len = self.key_match_fn(node.key, key)
+            total_prefix_length += prefix_len
+            key = key[prefix_len:]
+            value = value[prefix_len:]
+
+            if prefix_len < len(node.key):
+                new_node = self._split_node(node.key, node, prefix_len)
+                node = new_node
+
+            if len(key):
+                child_key = self.get_child_key_fn(key)
+
+        mamba_value_exist = False
+        if len(key):
+            new_node = TreeNode()
+            new_node.parent = node
+            new_node.key = key
+            new_node.value = value
+            new_node.mamba_value = mamba_value
+            self.full_lru_list.insert_mru(new_node)
+            self.full_evictable_size_ += len(value)
+            self.mamba_evictable_size_ += len(mamba_value)
+            self.mamba_lru_list.insert_mru(new_node)
+            node.children[child_key] = new_node
+        elif node.mamba_value is None:  # add for mamba tombstone
+            node.mamba_value = mamba_value
+            self.mamba_evictable_size_ += len(mamba_value)
+            self.mamba_lru_list.insert_mru(node)
+        else:
+            mamba_value_exist = True
+            self.mamba_lru_list.reset_node_mru(node)
+
+        return total_prefix_length, mamba_value_exist
+
+    def _iteratively_delete_tombstone_leaf(
+        self, node: TreeNode
+    ) -> Tuple[TreeNode, int]:
+        full_num_evicted = 0
+        while node.parent.mamba_value is None and len(node.parent.children) == 0:
+            # root node is not evictable
+            if node.parent == self.root_node:
+                break
+            # if locked, means node is in use, skip
+            if node.parent.full_lock_ref > 0:
+                break
+            assert (
+                node.parent.mamba_lock_ref == 0
+            ), f"tombstone mamba_lock_ref should always be 0, {node.parent.full_lock_ref=}, {node.parent.mamba_lock_ref=}, {node.parent.id=}"
+            # delete tombstone node evicts full tokens
+            self.token_to_kv_pool_allocator.free(node.parent.value)
+            full_num_evicted += len(node.parent.value)
+            self.full_lru_list.remove_node(node.parent)
+            self._delete_tombstone_leaf(node.parent)
+            node = node.parent
+
+        return node, full_num_evicted
+
+    def _delete_leaf(self, node: TreeNode) -> None:
+        assert (
+            node.mamba_value is not None
+        ), f"Invariant violated: leaf node is a tombstone, {node.id=}"
+        assert len(node.children) == 0, f"leaf node has children, {node.id=}"
+        for k, v in node.parent.children.items():
+            if v == node:
+                break
+        del node.parent.children[k]
+        self.full_evictable_size_ -= len(node.key)
+        self.mamba_evictable_size_ -= len(node.mamba_value)
+
+    def _tombstone_internal_node(self, node: TreeNode) -> None:
+        assert len(node.children) != 0, f"Cannot tombstone a leaf node, {node.id=}"
+        self.mamba_evictable_size_ -= len(node.mamba_value)
+        node.mamba_value = None
+
+    def _delete_tombstone_leaf(self, node: TreeNode) -> None:
+        assert (
+            node.mamba_value is None
+        ), f"Deleting a unexpected non-tombstone leaf node, {node.id=}"
+        assert len(node.children) == 0, f"leaf node has children, {node.id=}"
+        for k, v in node.parent.children.items():
+            if v == node:
+                break
+        del node.parent.children[k]
+        self.full_evictable_size_ -= len(node.key)
+
+    def _collect_leaves(self) -> List[TreeNode]:
+        ret_list = []
+        stack = [self.root_node]
+
+        while stack:
+            cur_node = stack.pop()
+            if len(cur_node.children) == 0:
+                ret_list.append(cur_node)
+            else:
+                stack.extend(cur_node.children.values())
+
+        return ret_list
+
+    def _collect_nontombstone_nodes(self) -> List[TreeNode]:
+        ret_list = []
+        stack = [self.root_node]
+
+        while stack:
+            cur_node = stack.pop()
+            if cur_node.mamba_value is not None:
+                ret_list.append(cur_node)
+            stack.extend(cur_node.children.values())
+
+        return ret_list
+
+    def _collect_all_nodes(self) -> List[TreeNode]:
+        ret_list = []
+        stack = [self.root_node]
+        while stack:
+            cur_node = stack.pop()
+            ret_list.append(cur_node)
+            stack.extend(cur_node.children.values())
+        return ret_list
+
+    def _print_helper(self, node: TreeNode, indent: int) -> None:
+        """Prints the radix tree in a human-readable format."""
+        stack = [(node, indent)]
+        while stack:
+            current_node, current_indent = stack.pop()
+            print(
+                " " * current_indent,
+                f"[{current_node.id}]",
+                len(current_node.key),
+                f"fr={current_node.full_lock_ref}",
+                f"mr={current_node.mamba_lock_ref}",
+                f"fll={self.full_lru_list.in_list(current_node)}",
+                f"mll={self.mamba_lru_list.in_list(current_node)}",
+                f"mv={current_node.mamba_value}",
+            )
+            for key, child in current_node.children.items():
+                stack.append((child, current_indent + 2))
+
+                assert key == self.get_child_key_fn(
+                    child.key
+                ), f"{key=}, {self.get_child_key_fn(child.key)=}"
+
+    def _total_size_helper(self) -> Tuple[int, int]:
+        total_size = 0
+        total_mamba_size = 0
+        stack = [self.root_node]
+        while stack:
+            current_node = stack.pop()
+            total_size += len(current_node.value)
+            if current_node.mamba_value is not None:
+                total_mamba_size += len(current_node.mamba_value)
+            for child in current_node.children.values():
+                if child.evicted:
+                    continue
+                stack.append(child)
+        return total_size, total_mamba_size

python/sglang/srt/mem_cache/memory_pool.py

@@ -190,6 +190,7 @@ class MambaPool:
             )
             logger.info(
                 f"Mamba Cache is allocated. "
+                f"max_mamba_cache_size: {size}, "
                 f"conv_state size: {get_tensor_size_bytes(conv_state) / GB:.2f}GB, "
                 f"ssm_state size: {get_tensor_size_bytes(temporal_state) / GB:.2f}GB "
                 f"intermediate_ssm_state_cache size: {get_tensor_size_bytes(intermediate_ssm_state_cache) / GB:.2f}GB "
@@ -199,11 +200,13 @@ class MambaPool:
             self.mamba_cache = self.State(conv=conv_state, temporal=temporal_state)
             logger.info(
                 f"Mamba Cache is allocated. "
+                f"max_mamba_cache_size: {size}, "
                 f"conv_state size: {get_tensor_size_bytes(conv_state) / GB:.2f}GB, "
                 f"ssm_state size: {get_tensor_size_bytes(temporal_state) / GB:.2f}GB "
             )
         self.size = size
-        self.free_slots = list(range(size))
+        self.device = device
+        self.free_slots = torch.arange(self.size, dtype=torch.int64, device=self.device)
         self.mem_usage = self.mamba_cache.mem_usage_bytes() / GB
 
     def get_speculative_mamba2_params_all_layers(self) -> SpeculativeState:
@@ -216,7 +219,7 @@ class MambaPool:
     def available_size(self):
         return len(self.free_slots)
 
-    def alloc(self, need_size: int) -> Optional[List[int]]:
+    def alloc(self, need_size: int) -> Optional[torch.Tensor]:
         if need_size > len(self.free_slots):
             return None
 
@@ -225,17 +228,30 @@ class MambaPool:
 
         return select_index
 
-    def free(self, free_index: Union[int, List[int]]):
-        if isinstance(free_index, (int,)):
-            self.free_slots.append(free_index)
-        else:
-            self.free_slots.extend(free_index)
+    def free(self, free_index: torch.Tensor):
+        if free_index.numel() == 0:
+            return
+        self.free_slots = torch.cat((self.free_slots, free_index))
         self.mamba_cache.conv[:, free_index] = self.mamba_cache.temporal[
             :, free_index
         ] = 0
 
     def clear(self):
-        self.free_slots = list(range(self.size))
+        self.free_slots = torch.arange(self.size, dtype=torch.int64, device=self.device)
+
+    def copy_from(self, src_index: torch.Tensor, dst_index: torch.Tensor):
+        self.mamba_cache.conv[:, dst_index] = self.mamba_cache.conv[:, src_index]
+        self.mamba_cache.temporal[:, dst_index] = self.mamba_cache.temporal[
+            :, src_index
+        ]
+        return
+
+    def fork_from(self, src_index: torch.Tensor) -> Optional[torch.Tensor]:
+        dst_index = self.alloc(1)
+        if dst_index == None:
+            return None
+        self.copy_from(src_index, dst_index)
+        return dst_index
 
 
 class HybridReqToTokenPool(ReqToTokenPool):
@@ -245,6 +261,7 @@ class HybridReqToTokenPool(ReqToTokenPool):
         self,
         *,
         size: int,
+        mamba_size: int,
         max_context_len: int,
         device: str,
         enable_memory_saver: bool,
@@ -259,7 +276,7 @@ class HybridReqToTokenPool(ReqToTokenPool):
         )
 
         self.mamba_pool = MambaPool(
-            size=size,
+            size=mamba_size,
             cache_params=cache_params,
             device=device,
             speculative_num_draft_tokens=speculative_num_draft_tokens,
@@ -271,9 +288,6 @@ class HybridReqToTokenPool(ReqToTokenPool):
             size, dtype=torch.int32, device=self.device
         )
 
-        self.rid_to_mamba_index_mapping: Dict[str, int] = {}
-        self.mamba_index_to_rid_mapping: Dict[int, str] = {}
-
     # For chunk prefill req, we do not need to allocate mamba cache,
     # We could use allocated mamba cache instead.
     def alloc(
@@ -285,14 +299,14 @@ class HybridReqToTokenPool(ReqToTokenPool):
 
         mamba_index = []
         for req in reqs:
-            rid = req.rid
-            if rid in self.rid_to_mamba_index_mapping:
-                mid = self.rid_to_mamba_index_mapping[rid]
-            elif (mid := self.mamba_pool.alloc(1)) is not None:
-                mid = mid[0]
-                self.rid_to_mamba_index_mapping[rid] = mid
-                self.mamba_index_to_rid_mapping[mid] = rid
-            mamba_index.append(mid)
+            mid = None
+            if req.mamba_pool_idx is not None:  # for radix cache
+                mid = req.mamba_pool_idx
+            else:
+                mid = self.mamba_pool.alloc(1)[0]
+                req.mamba_pool_idx = mid
+            if mid is not None:
+                mamba_index.append(mid)
         assert len(select_index) == len(
             mamba_index
         ), f"Not enough space for mamba cache, try to increase --max-mamba-cache-size."
@@ -313,17 +327,12 @@ class HybridReqToTokenPool(ReqToTokenPool):
 
     # For chunk prefill, we can not free mamba cache, we need use it in the future
     def free(self, free_index: Union[int, List[int]], free_mamba_cache: bool = True):
+        if isinstance(free_index, (int,)):
+            free_index = [free_index]
         super().free(free_index)
         if free_mamba_cache:
             mamba_index = self.req_index_to_mamba_index_mapping[free_index]
-            mamba_index_list = mamba_index.tolist()
-            if isinstance(mamba_index_list, int):
-                mamba_index_list = [mamba_index_list]
-            self.mamba_pool.free(mamba_index_list)
-            for mid in mamba_index_list:
-                rid = self.mamba_index_to_rid_mapping[mid]
-                self.mamba_index_to_rid_mapping.pop(mid)
-                self.rid_to_mamba_index_mapping.pop(rid)
+            self.mamba_pool.free(mamba_index)
 
     def clear(self):
         super().clear()

python/sglang/srt/model_executor/model_runner.py

@@ -191,6 +191,9 @@ SGLANG_CI_SMALL_KV_SIZE = os.getenv("SGLANG_CI_SMALL_KV_SIZE", None)
 # Detect stragger ranks in model loading
 UNBALANCED_MODEL_LOADING_TIMEOUT_S = 300
 
+# the ratio of mamba cache pool size to max_running_requests, it will be safe when it is larger than 2 (yizhang2077)
+MAMBA_CACHE_SIZE_MAX_RUNNING_REQUESTS_RATIO = 3
+
 logger = logging.getLogger(__name__)
 
 
@@ -382,26 +385,10 @@ class ModelRunner:
             if architectures and not any("Llama4" in arch for arch in architectures):
                 self.is_hybrid = self.model_config.is_hybrid = True
 
-        if config := self.mambaish_config:
+        if config := self.mamba2_config:
             class_name = config.__class__.__name__
             logger.warning(f"{class_name} model detected, disable radix cache")
             self.server_args.disable_radix_cache = True
-            if self.server_args.max_mamba_cache_size is None:
-                if self.server_args.max_running_requests is not None:
-                    self.server_args.max_mamba_cache_size = (
-                        self.server_args.max_running_requests
-                    )
-                else:
-                    self.server_args.max_mamba_cache_size = 512
-        if self.hybrid_gdn_config is not None:
-            self.server_args.max_mamba_cache_size = (
-                self.server_args.max_mamba_cache_size
-                // (
-                    self.server_args.dp_size
-                    if self.server_args.enable_dp_attention
-                    else 1
-                )
-            )
 
         # For MTP models like DeepSeek-V3 or GLM-4.5, the MTP layer(s) are used separately as draft
         # models for speculative decoding. In those cases, `num_nextn_predict_layers` is used to
@@ -1330,15 +1317,60 @@ class ModelRunner:
         rest_memory = available_gpu_memory - total_gpu_memory * (
             1 - self.mem_fraction_static
         )
-        if config := self.mambaish_config:
-            rest_memory -= (
-                self.server_args.max_mamba_cache_size
-                * config.mamba2_cache_params.mamba_cache_per_req
-                / (1 << 30)
-            )
+        if self.mambaish_config is not None:
+            rest_memory = self.handle_max_mamba_cache(rest_memory)
         max_num_token = int(rest_memory * (1 << 30) // cell_size)
         return max_num_token
 
+    def handle_max_mamba_cache(self, total_rest_memory):
+        config = self.mambaish_config
+        server_args = self.server_args
+        assert config is not None
+
+        speculativa_ratio = (
+            0
+            if server_args.speculative_num_draft_tokens is None
+            else server_args.speculative_num_draft_tokens
+        )
+        if (
+            server_args.disable_radix_cache
+            or config.mamba2_cache_params.mamba_cache_per_req == 0
+        ):
+            # with disable radix cache, sets the max_mamba_cache_size based on the max_running_requests
+            if server_args.max_mamba_cache_size is None:
+                if server_args.max_running_requests is not None:
+                    server_args.max_mamba_cache_size = server_args.max_running_requests
+                else:
+                    server_args.max_mamba_cache_size = 512
+        else:
+            # allocate the memory based on the ratio between mamba state memory vs. full kv cache memory
+            # solve the equations:
+            # 1. mamba_state_memory + full_kv_cache_memory == total_rest_memory
+            # 2. mamba_state_memory / full_kv_cache_memory == server_args.mamba_full_memory_ratio
+            mamba_state_memory_raw = (
+                total_rest_memory
+                * server_args.mamba_full_memory_ratio
+                / (1 + server_args.mamba_full_memory_ratio)
+            )
+            # calculate the max_mamba_cache_size based on the given total mamba memory
+            server_args.max_mamba_cache_size = int(
+                (mamba_state_memory_raw * (1 << 30))
+                // config.mamba2_cache_params.mamba_cache_per_req
+                // (1 + speculativa_ratio)
+            )
+
+        if self.hybrid_gdn_config is not None:
+            server_args.max_mamba_cache_size = server_args.max_mamba_cache_size // (
+                server_args.dp_size if server_args.enable_dp_attention else 1
+            )
+        mamba_state_memory = (
+            server_args.max_mamba_cache_size
+            * config.mamba2_cache_params.mamba_cache_per_req
+            * (1 + speculativa_ratio)
+            / (1 << 30)
+        )
+        return total_rest_memory - mamba_state_memory
+
     @property
     def hybrid_gdn_config(self):
         config = self.model_config.hf_config
@@ -1511,8 +1543,16 @@ class ModelRunner:
                 ),
                 4096,
             )
+
         if self.mambaish_config is not None:
-            max_num_reqs = min(max_num_reqs, self.server_args.max_mamba_cache_size)
+            ratio = (
+                MAMBA_CACHE_SIZE_MAX_RUNNING_REQUESTS_RATIO
+                if not self.server_args.disable_radix_cache
+                else 1
+            )
+            max_num_reqs = min(
+                max_num_reqs, self.server_args.max_mamba_cache_size // ratio
+            )
 
         if self.spec_algorithm.is_eagle() or self.spec_algorithm.is_standalone():
             if self.is_draft_worker:
@@ -1595,6 +1635,7 @@ class ModelRunner:
             elif config := self.mambaish_config:
                 self.req_to_token_pool = HybridReqToTokenPool(
                     size=max_num_reqs,
+                    mamba_size=self.server_args.max_mamba_cache_size,
                     max_context_len=self.model_config.context_len
                     + extra_max_context_len,
                     device=self.device,

python/sglang/srt/server_args.py

@@ -362,6 +362,7 @@ class ServerArgs:
     # Mamba cache
     max_mamba_cache_size: Optional[int] = None
     mamba_ssm_dtype: str = "float32"
+    mamba_full_memory_ratio: float = 0.2
 
     # Hierarchical cache
     enable_hierarchical_cache: bool = False
@@ -2433,6 +2434,12 @@ class ServerArgs:
             choices=["float32", "bfloat16"],
             help="The data type of the SSM states in mamba cache.",
         )
+        parser.add_argument(
+            "--mamba-full-memory-ratio",
+            type=float,
+            default=ServerArgs.mamba_full_memory_ratio,
+            help="The ratio of mamba state memory to full kv cache memory.",
+        )
         # Args for multi-item-scoring
         parser.add_argument(
             "--multi-item-scoring-delimiter",

test/srt/run_suite.py

@@ -84,6 +84,7 @@ suites = {
         TestFile("test_io_struct.py", 8),
         TestFile("test_jinja_template_utils.py", 1),
         TestFile("test_logprobs.py", 55),
+        TestFile("test_mamba_unittest.py", 4),
         TestFile("test_metrics.py", 32),
         TestFile("test_metrics_utils.py", 1),
         TestFile("test_mla.py", 167),

test/srt/test_mamba_unittest.py

+import inspect
+import os
+import unittest
+
+import torch
+
+from sglang.srt.configs.mamba_utils import Mamba2CacheParams, Mamba2StateShape
+from sglang.srt.managers.schedule_batch import Req
+from sglang.srt.mem_cache.allocator import TokenToKVPoolAllocator
+from sglang.srt.mem_cache.mamba_radix_cache import MambaRadixCache
+from sglang.srt.mem_cache.memory_pool import HybridLinearKVPool, HybridReqToTokenPool
+from sglang.srt.mem_cache.radix_cache import RadixKey
+from sglang.srt.sampling.sampling_params import SamplingParams
+
+
+class TestMamba(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        pass
+
+    @classmethod
+    def tearDownClass(cls):
+        pass
+
+    def test_hybrid_linear_kv_pool(self):
+        size = 16
+        head_num = 2
+        head_dim = 256
+        num_layers = 48
+        global_interval = 4
+        dtype = torch.bfloat16
+        device = "cuda"
+        full_attention_layer_ids = [
+            i for i in range(global_interval - 1, num_layers, global_interval)
+        ]
+        pool = HybridLinearKVPool(
+            size=size,
+            dtype=dtype,
+            page_size=1,
+            head_num=head_num,
+            head_dim=head_dim,
+            full_attention_layer_ids=full_attention_layer_ids,
+            enable_kvcache_transpose=False,
+            device=device,
+        )
+        assert pool._transfer_full_attention_id(global_interval - 1) == 0
+        assert pool._transfer_full_attention_id(2 * global_interval - 1) == 1
+        with self.assertRaises(ValueError) as context:
+            pool._transfer_full_attention_id(1)
+        self.assertIn(
+            "layer_id=1 not in full attention layers:", str(context.exception)
+        )
+
+    def test_mamba_pool(self):
+        max_num_reqs = 10
+        mamba_cache_size = 20
+        max_context_len = 128
+        device = "cuda"
+        global_interval = 4
+        num_layers = 48
+        full_attention_layer_ids = [
+            i for i in range(global_interval - 1, num_layers, global_interval)
+        ]
+        mamba_layers = [
+            i for i in range(num_layers) if i not in full_attention_layer_ids
+        ]
+        shape = Mamba2StateShape.create(
+            tp_world_size=1,
+            intermediate_size=4096,
+            n_groups=16,
+            num_heads=32,
+            head_dim=128,
+            state_size=128,
+            conv_kernel=4,
+        )
+        os.environ["SGLANG_MAMBA_SSM_DTYPE"] = "bfloat16"
+        mamba2_cache_params = Mamba2CacheParams(shape=shape, layers=mamba_layers)
+
+        req_to_token_pool = HybridReqToTokenPool(
+            size=max_num_reqs,
+            mamba_size=mamba_cache_size,
+            max_context_len=max_context_len,
+            device=device,
+            enable_memory_saver=False,
+            cache_params=mamba2_cache_params,
+            speculative_num_draft_tokens=3,
+        )
+
+        assert req_to_token_pool.available_size() == max_num_reqs
+        assert req_to_token_pool.mamba_pool.available_size() == mamba_cache_size
+
+        sampling_params = SamplingParams(
+            temperature=0,
+            max_new_tokens=1,
+        )
+        req = Req(
+            rid=0,
+            origin_input_text="",
+            origin_input_ids=[],
+            sampling_params=sampling_params,
+        )
+
+        # alloc req
+        req_index = req_to_token_pool.alloc(1, [req])
+        assert req_to_token_pool.available_size() == max_num_reqs - 1
+        assert req_to_token_pool.mamba_pool.available_size() == mamba_cache_size - 1
+
+        # free req
+        req_to_token_pool.free(req_index)
+        assert req_to_token_pool.available_size() == max_num_reqs
+        assert req_to_token_pool.mamba_pool.available_size() == mamba_cache_size
+
+        # alloc req without free mamba cache
+        req.mamba_pool_idx = None
+        req_index = req_to_token_pool.alloc(1, [req])
+        req_to_token_pool.free(req_index, free_mamba_cache=False)
+        assert req_to_token_pool.available_size() == max_num_reqs
+        assert req_to_token_pool.mamba_pool.available_size() == mamba_cache_size - 1
+
+        # alloc again
+        req_index = req_to_token_pool.alloc(1, [req])
+        assert req_to_token_pool.available_size() == max_num_reqs - 1
+        assert req_to_token_pool.mamba_pool.available_size() == mamba_cache_size - 1
+
+    def test_mamba_radix_cache_1(self):
+        # kv cache
+        size = 128
+        dtype = torch.bfloat16
+        head_num = 2
+        head_dim = 256
+        num_layers = 48
+        global_interval = 4
+        max_num_reqs = 10
+        mamba_cache_size = 20
+        max_context_len = 128
+        device = "cuda"
+        full_attention_layer_ids = [
+            i for i in range(global_interval - 1, num_layers, global_interval)
+        ]
+
+        # mamba
+        mamba_layers = [
+            i for i in range(num_layers) if i not in full_attention_layer_ids
+        ]
+        os.environ["SGLANG_MAMBA_SSM_DTYPE"] = "bfloat16"
+        shape = Mamba2StateShape.create(
+            tp_world_size=1,
+            intermediate_size=4096,
+            n_groups=16,
+            num_heads=32,
+            head_dim=128,
+            state_size=128,
+            conv_kernel=4,
+        )
+        mamba2_cache_params = Mamba2CacheParams(shape=shape, layers=mamba_layers)
+
+        req_to_token_pool = HybridReqToTokenPool(
+            size=max_num_reqs,
+            mamba_size=mamba_cache_size,
+            max_context_len=max_context_len,
+            device=device,
+            enable_memory_saver=False,
+            cache_params=mamba2_cache_params,
+            speculative_num_draft_tokens=3,
+        )
+        # setup kv pool
+        pool = HybridLinearKVPool(
+            size=size,
+            dtype=dtype,
+            page_size=1,
+            head_num=head_num,
+            head_dim=head_dim,
+            full_attention_layer_ids=full_attention_layer_ids,
+            enable_kvcache_transpose=False,
+            device=device,
+        )
+
+        # setup token to kv pool allocator
+        allocator = TokenToKVPoolAllocator(
+            size=size,
+            dtype=dtype,
+            device=device,
+            kvcache=pool,
+            need_sort=False,
+        )
+        # setup radix cache
+        tree = MambaRadixCache(
+            req_to_token_pool=req_to_token_pool,
+            token_to_kv_pool_allocator=allocator,
+            page_size=1,
+            disable=False,
+        )
+
+        def make_dummy_req():
+            sampling_params = SamplingParams(
+                temperature=0,
+                max_new_tokens=1,
+            )
+            req = Req(
+                rid=0,
+                origin_input_text="",
+                origin_input_ids=[],
+                sampling_params=sampling_params,
+            )
+            req_to_token_pool.alloc(1, reqs=[req])
+            return req
+
+        mamba_pool = req_to_token_pool.mamba_pool
+        # test
+        print(
+            f"[Start] allocator mamba available size: {mamba_pool.available_size()}, full available size: {allocator.available_size()}"
+        )
+        req1 = make_dummy_req()
+        req1_token_ids, req1_kv_indices = [1, 2, 3], allocator.alloc(3)
+        assert len(req1_token_ids) == len(req1_kv_indices)
+        print(
+            f"req1: inserting, req1_token_ids: {req1_token_ids}, req1_kv_indices: {req1_kv_indices}"
+        )
+        prefix_len = tree.insert(
+            RadixKey(req1_token_ids), req1_kv_indices, req1.mamba_pool_idx.unsqueeze(0)
+        )
+        print(
+            f"req1: prefix_len: {prefix_len}, allocator mamba available size: {mamba_pool.available_size()}, full available size: {allocator.available_size()}"
+        )
+        req2 = make_dummy_req()
+        req2_token_ids, req2_kv_indices = [1, 2, 3, 4, 5, 6, 7], allocator.alloc(7)
+        assert len(req2_token_ids) == len(req2_kv_indices)
+        print(
+            f"req2: inserting, req2_token_ids: {req2_token_ids}, req2_kv_indices: {req2_kv_indices}"
+        )
+        prefix_len = tree.insert(
+            RadixKey(req2_token_ids), req2_kv_indices, req2.mamba_pool_idx.unsqueeze(0)
+        )
+        print(
+            f"req2: prefix_len: {prefix_len}, allocator mamba available size: {mamba_pool.available_size()}, full available size: {allocator.available_size()}"
+        )
+
+        req3 = make_dummy_req()
+        req3_token_ids, req3_kv_indices = [10, 11, 12], allocator.alloc(3)
+        assert len(req3_token_ids) == len(req3_kv_indices)
+        print(
+            f"req3: inserting, req3_token_ids: {req3_token_ids}, req3_kv_indices: {req3_kv_indices}"
+        )
+        prefix_len = tree.insert(
+            RadixKey(req3_token_ids), req3_kv_indices, req3.mamba_pool_idx.unsqueeze(0)
+        )
+        print(
+            f"req3: prefix_len: {prefix_len}, allocator mamba available size: {mamba_pool.available_size()}, full available size: {allocator.available_size()}"
+        )
+        req4 = make_dummy_req()
+        req4_token_ids, req4_kv_indices = [1, 2, 3, 4, 5, 60, 70], allocator.alloc(7)
+        assert len(req4_token_ids) == len(req4_kv_indices)
+        print(
+            f"req4: inserting, req4_token_ids: {req4_token_ids}, req4_kv_indices: {req4_kv_indices}"
+        )
+        prefix_len = tree.insert(
+            RadixKey(req4_token_ids), req4_kv_indices, req4.mamba_pool_idx.unsqueeze(0)
+        )
+        print(
+            f"req4: prefix_len: {prefix_len}, allocator mamba available size: {mamba_pool.available_size()}, full available size: {allocator.available_size()}"
+        )
+
+        tree.pretty_print()
+        full_num_tokens = 1
+        print(f"evicting {full_num_tokens} full token")
+        tree.evict(full_num_tokens=full_num_tokens)
+        tree.pretty_print()
+
+        mamba_num = 1
+        print(f"evicting {mamba_num} mamba")
+        tree.evict_mamba(mamba_num=mamba_num)
+        tree.pretty_print()
+
+        req5_token_ids = [1, 2, 3, 4, 5]
+        result = tree.match_prefix(RadixKey(req5_token_ids))
+        kv_indices, last_node = result.device_indices, result.last_device_node
+        print(
+            f"req5: token_ids: {req5_token_ids}, matched kv_indices: {kv_indices}, last_node.key: {last_node.key}"
+        )
+        assert len(kv_indices) == 0
+
+        req6_token_ids = [1, 2, 3, 4, 5, 60, 70]
+        result = tree.match_prefix(RadixKey(req6_token_ids))
+        kv_indices, last_node = result.device_indices, result.last_device_node
+        print(
+            f"req6: token_ids: {req6_token_ids}, matched kv_indices: {kv_indices}, last_node.key: {last_node.key}"
+        )
+        assert len(kv_indices) == 7
+        assert len(last_node.key) == 2
+
+        req7_token_ids = [1, 2, 3, 4, 5, 6, 7]
+        result = tree.match_prefix(RadixKey(req7_token_ids))
+        kv_indices, last_node = result.device_indices, result.last_device_node
+        print(
+            f"req7: token_ids: {req7_token_ids}, matched kv_indices: {kv_indices}, last_node.key: {last_node.key}"
+        )
+        assert len(kv_indices) == 7
+        assert len(last_node.key) == 2
+
+        mamba_num = 1
+        print(f"evicting {mamba_num} mamba")
+        tree.evict_mamba(mamba_num=mamba_num)
+        tree.pretty_print()
+
+        req8_token_ids = [1, 2, 3, 4, 5, 60, 70]
+        result = tree.match_prefix(RadixKey(req8_token_ids))
+        kv_indices, last_node = result.device_indices, result.last_device_node
+        print(
+            f"req8: token_ids: {req8_token_ids}, matched kv_indices: {kv_indices}, last_node.key: {last_node.key}"
+        )
+        assert len(kv_indices) == 0
+        assert len(last_node.key) == 0
+
+        req9_token_ids = [1, 2, 3, 4, 5, 6, 7]
+        req9 = make_dummy_req()
+        result = tree.match_prefix(
+            RadixKey(req9_token_ids), **({"req": req9, "cow_mamba": True})
+        )
+        kv_indices, last_node = result.device_indices, result.last_device_node
+        assert req9.mamba_pool_idx is not None
+        assert torch.all(
+            mamba_pool.mamba_cache.conv[:, req9.mamba_pool_idx]
+            == mamba_pool.mamba_cache.conv[:, last_node.mamba_value]
+        )
+        assert torch.all(
+            mamba_pool.mamba_cache.temporal[:, req9.mamba_pool_idx]
+            == mamba_pool.mamba_cache.temporal[:, last_node.mamba_value]
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()