[HiCache] resolve conflict between chunked-prefill and hicache hit count (#9776)

python/sglang/srt/disaggregation/prefill.py

@@ -567,7 +567,7 @@ class SchedulerDisaggregationPrefillMixin:
                 # Move the chunked request out of the batch so that we can merge
                 # only finished requests to running_batch.
                 self.last_batch.filter_batch(chunked_req_to_exclude=self.chunked_req)
-                self.tree_cache.cache_unfinished_req(self.chunked_req)
+                self.tree_cache.cache_unfinished_req(self.chunked_req, chunked=True)
                 if self.enable_overlap:
                     # Delay KV transfer to process_batch_result_disagg_prefill when overlap is enabled to ensure results are resolved
                     self.chunked_req.tmp_end_idx = min(

python/sglang/srt/managers/scheduler.py

@@ -1503,7 +1503,7 @@ class Scheduler(
             # Move the chunked request out of the batch so that we can merge
             # only finished requests to running_batch.
             chunked_req_to_exclude.add(self.chunked_req)
-            self.tree_cache.cache_unfinished_req(self.chunked_req)
+            self.tree_cache.cache_unfinished_req(self.chunked_req, chunked=True)
             # chunked request keeps its rid but will get a new req_pool_idx
             self.req_to_token_pool.free(self.chunked_req.req_pool_idx)
         if self.last_batch and self.last_batch.forward_mode.is_extend():

python/sglang/srt/mem_cache/chunk_cache.py

@@ -47,7 +47,7 @@ class ChunkCache(BasePrefixCache):
         self.req_to_token_pool.free(req.req_pool_idx)
         self.token_to_kv_pool_allocator.free(kv_indices)
 
-    def cache_unfinished_req(self, req: Req):
+    def cache_unfinished_req(self, req: Req, chunked=False):
         kv_indices = self.req_to_token_pool.req_to_token[
             req.req_pool_idx, : len(req.fill_ids)
         ]

python/sglang/srt/mem_cache/hiradix_cache.py

@@ -102,7 +102,7 @@ class HiRadixCache(RadixCache):
         self.ongoing_backup = {}
         # todo: dynamically adjust the threshold
         self.write_through_threshold = (
-            1 if hicache_write_policy == "write_through" else 3
+            1 if hicache_write_policy == "write_through" else 2
         )
         self.write_through_threshold_storage = (
             1 if hicache_write_policy == "write_through" else 3
@@ -155,8 +155,9 @@ class HiRadixCache(RadixCache):
         self.ongoing_backup[operation_id] = node
         node.protect_host()
 
-    def inc_hit_count(self, node: TreeNode):
+    def _inc_hit_count(self, node: TreeNode, chunked=False):
-        if self.cache_controller.write_policy == "write_back":
+        # skip the hit count update for chunked requests
+        if self.cache_controller.write_policy == "write_back" or chunked:
             return
         node.hit_count += 1
 
@@ -672,11 +673,11 @@ class HiRadixCache(RadixCache):
         new_node.parent.children[self.get_child_key_fn(key)] = new_node
         return new_node
 
-    def _insert_helper(self, node: TreeNode, key: List, value):
+    def insert(self, key: List, value, chunked=False):
-        node.last_access_time = time.monotonic()
         if len(key) == 0:
             return 0
 
+        node = self.root_node
         child_key = self.get_child_key_fn(key)
         total_prefix_length = 0
 
@@ -693,7 +694,7 @@ class HiRadixCache(RadixCache):
                     self.token_to_kv_pool_host.update_synced(node.host_value)
                     self.evictable_size_ += len(node.value)
                 else:
-                    self.inc_hit_count(node)
+                    self._inc_hit_count(node, chunked)
                     total_prefix_length += prefix_len
             else:
                 # partial match, split the node
@@ -703,7 +704,7 @@ class HiRadixCache(RadixCache):
                     self.token_to_kv_pool_host.update_synced(new_node.host_value)
                     self.evictable_size_ += len(new_node.value)
                 else:
-                    self.inc_hit_count(new_node)
+                    self._inc_hit_count(new_node, chunked)
                     total_prefix_length += prefix_len
                 node = new_node
 
@@ -737,7 +738,7 @@ class HiRadixCache(RadixCache):
                     last_hash = new_node.hash_value[-1]
 
             if self.cache_controller.write_policy != "write_back":
-                self.inc_hit_count(new_node)
+                self._inc_hit_count(new_node, chunked)
         return total_prefix_length
 
     def _collect_leaves_device(self):

python/sglang/srt/mem_cache/lora_radix_cache.py

@@ -183,7 +183,7 @@ class LoRARadixCache(BasePrefixCache):
         self.req_to_token_pool.free(req.req_pool_idx)
         self.dec_lock_ref(req.last_node)
 
-    def cache_unfinished_req(self, req: Req):
+    def cache_unfinished_req(self, req: Req, chunked=False):
         """Cache request when it is unfinished."""
         if self.disable:
             return

python/sglang/srt/mem_cache/radix_cache.py

@@ -195,7 +195,7 @@ class RadixCache(BasePrefixCache):
             last_host_node=last_node,
         )
 
-    def insert(self, key: List, value=None):
+    def insert(self, key: List, value=None, chunked=False):
         if self.disable:
             return 0
 
@@ -240,7 +240,7 @@ class RadixCache(BasePrefixCache):
         self.req_to_token_pool.free(req.req_pool_idx)
         self.dec_lock_ref(req.last_node)
 
-    def cache_unfinished_req(self, req: Req):
+    def cache_unfinished_req(self, req: Req, chunked=False):
         """Cache request when it is unfinished."""
         if self.disable:
             return
@@ -261,7 +261,9 @@ class RadixCache(BasePrefixCache):
         page_aligned_token_ids = token_ids[:page_aligned_len]
 
         # Radix Cache takes one ref in memory pool
-        new_prefix_len = self.insert(page_aligned_token_ids, page_aligned_kv_indices)
+        new_prefix_len = self.insert(
+            page_aligned_token_ids, page_aligned_kv_indices, chunked=chunked
+        )
         self.token_to_kv_pool_allocator.free(
             kv_indices[len(req.prefix_indices) : new_prefix_len]
         )

python/sglang/srt/mem_cache/radix_cache_cpp.py

@@ -181,7 +181,7 @@ class RadixCacheCpp(BasePrefixCache):
         self.dec_lock_ref(req.last_node)
         self.req_to_token_pool.free(req.req_pool_idx)
 
-    def cache_unfinished_req(self, req: Req):
+    def cache_unfinished_req(self, req: Req, chunked=False):
         """Cache request when it is unfinished."""
         assert req.req_pool_idx is not None
         token_ids = req.fill_ids

python/sglang/srt/mem_cache/swa_radix_cache.py

@@ -464,7 +464,7 @@ class SWARadixCache(BasePrefixCache):
         self.req_to_token_pool.free(req.req_pool_idx)
         self.dec_lock_ref(req.last_node, req.swa_uuid_for_lock)
 
-    def cache_unfinished_req(self, req: Req) -> None:
+    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[