Reduce the overhead when cache is disabled (#1010)

python/sglang/srt/managers/policy_scheduler.py

@@ -18,44 +18,40 @@ limitations under the License.
 import random
 from collections import defaultdict
 from contextlib import contextmanager
+from typing import List
 
 from sglang.srt.managers.schedule_batch import Req, ScheduleBatch
 
 
 class PolicyScheduler:
-    def __init__(
-        self,
-        policy,
-        max_running_seqs,
-        max_prefill_num_tokens,
-        max_total_num_tokens,
-        tree_cache,
-    ):
-        if tree_cache.disable and policy == "lpm":
-            # LMP is meaningless when the tree cache is disabled.
+    def __init__(self, policy, tree_cache):
+        if tree_cache.disable and policy in ["lpm", "dfs-weight"]:
+            # LPM and DFS-weight is meaningless when the tree cache is disabled.
             policy = "fcfs"
 
         self.policy = policy
-        self.max_running_seqs = max_running_seqs
-        self.max_prefill_num_tokens = max_prefill_num_tokens
-        self.max_total_num_tokens = max_total_num_tokens
         self.tree_cache = tree_cache
 
-    def get_priority_queue(self, waiting_queue):
+    def calc_priority(self, waiting_queue: List[Req]):
+        if self.policy in ["lpm", "dfs-weight"]:
+            # Compute matched prefix length
+            for r in waiting_queue:
+                # NOTE: the prefix_indices must always be aligned with last_node
+                r.prefix_indices, r.last_node = self.tree_cache.match_prefix(
+                    rid=r.rid, key=r.adjust_max_prefix_ids()
+                )
+
         if self.policy == "lpm":
-            # longest prefix match
+            # Longest Prefix Match
             waiting_queue.sort(key=lambda x: -len(x.prefix_indices))
-            return waiting_queue
         elif self.policy == "fcfs":
             # first come first serve
-            return waiting_queue
+            pass
         elif self.policy == "lof":
             # longest output first
             waiting_queue.sort(key=lambda x: -x.sampling_params.max_new_tokens)
-            return waiting_queue
         elif self.policy == "random":
             random.shuffle(waiting_queue)
-            return waiting_queue
         elif self.policy == "dfs-weight":
             last_node_to_reqs = defaultdict(list)
             for req in waiting_queue:
@@ -66,12 +62,13 @@ class PolicyScheduler:
                 node_to_weight[node] = len(last_node_to_reqs[node])
             self.calc_weight(self.tree_cache.root_node, node_to_weight)
 
-            q = []
+            waiting_queue.clear()
             self.get_dfs_priority(
-                self.tree_cache.root_node, node_to_weight, last_node_to_reqs, q
+                self.tree_cache.root_node,
+                node_to_weight,
+                last_node_to_reqs,
+                waiting_queue,
             )
-            assert len(q) == len(waiting_queue)
-            return q
         else:
             raise ValueError(f"Unknown schedule_policy: {self.policy}")
 
@@ -139,8 +136,6 @@ class PrefillAdder:
         self.log_input_tokens += extend_input_len
 
     def add_inflight_req(self, req: Req):
-        req.input_ids = req.origin_input_ids + req.output_ids
-        req.extend_input_len = len(req.input_ids) - len(req.prefix_indices)
         truncated = req.extend_input_len > self.rem_chunk_tokens
         req.extend_input_len = min(req.extend_input_len, self.rem_chunk_tokens)
         req.input_ids = req.input_ids[: len(req.prefix_indices) + req.extend_input_len]

python/sglang/srt/managers/schedule_batch.py

@@ -164,7 +164,12 @@ class Req:
     def finished(self) -> bool:
         return self.finished_reason is not None
 
+    def init_next_round_input(self):
+        self.input_ids = self.origin_input_ids + self.output_ids
+        self.extend_input_len = len(self.input_ids) - len(self.prefix_indices)
+
     def adjust_max_prefix_ids(self):
+        self.input_ids = self.origin_input_ids + self.output_ids
         input_len = len(self.input_ids)
         max_prefix_len = input_len
 

python/sglang/srt/managers/tp_worker.py

@@ -165,13 +165,7 @@ class ModelTpServer:
                 disable=server_args.disable_radix_cache,
             )
         self.tree_cache_metrics = {"total": 0, "hit": 0}
-        self.scheduler = PolicyScheduler(
-            self.schedule_policy,
-            self.max_running_requests,
-            self.max_prefill_tokens,
-            self.max_total_num_tokens,
-            self.tree_cache,
-        )
+        self.scheduler = PolicyScheduler(self.schedule_policy, self.tree_cache)
         self.req_to_token_pool = self.model_runner.req_to_token_pool
         self.token_to_kv_pool = self.model_runner.token_to_kv_pool
 
@@ -373,17 +367,8 @@ class ModelTpServer:
         if running_bs >= self.max_running_requests:
             return None
 
-        # Compute matched prefix length
-        for req in self.waiting_queue:
-            req.input_ids = req.origin_input_ids + req.output_ids
-            # NOTE: the prefix_indices must always be aligned with last_node
-            req.prefix_indices, req.last_node = self.tree_cache.match_prefix(
-                rid=req.rid, key=req.adjust_max_prefix_ids()
-            )
-            req.extend_input_len = len(req.input_ids) - len(req.prefix_indices)
-
         # Get priority queue
-        self.waiting_queue = self.scheduler.get_priority_queue(self.waiting_queue)
+        self.scheduler.calc_priority(self.waiting_queue)
 
         adder = PrefillAdder(
             self.tree_cache,
@@ -397,12 +382,13 @@ class ModelTpServer:
 
         has_inflight = self.current_inflight_req is not None
         if self.current_inflight_req is not None:
+            self.current_inflight_req.init_next_round_input()
             self.current_inflight_req = adder.add_inflight_req(
                 self.current_inflight_req
             )
 
         for req in self.waiting_queue:
-
+            req.init_next_round_input()
             res = adder.add_one_req(req)
             if (
                 not res

python/sglang/srt/mem_cache/radix_cache.py

@@ -169,6 +169,9 @@ class RadixCache(BasePrefixCache):
                 heapq.heappush(leaves, x.parent)
 
     def inc_lock_ref(self, node: TreeNode):
+        if self.disable:
+            return 0
+
         delta = 0
         while node != self.root_node:
             if node.lock_ref == 0:
@@ -179,6 +182,9 @@ class RadixCache(BasePrefixCache):
         return delta
 
     def dec_lock_ref(self, node: TreeNode):
+        if self.disable:
+            return 0
+
         delta = 0
         while node != self.root_node:
             if node.lock_ref == 1: