Fix memory leak for chunked prefill 2 (#1858)

Co-authored-by: Liangsheng Yin <hnyls2002@gmail.com>

.github/workflows/pr-test.yml

@@ -50,7 +50,7 @@ jobs:
         timeout-minutes: 20
         run: |
           cd test/srt
-          python3 run_suite.py --suite minimal --range-begin 0 --range-end 5
+          python3 run_suite.py --suite minimal --range-begin 0 --range-end 4
 
   unit-test-backend-part-2:
     if: github.repository == 'sgl-project/sglang' || github.event_name == 'pull_request'
@@ -67,7 +67,7 @@ jobs:
         timeout-minutes: 20
         run: |
           cd test/srt
-          python3 run_suite.py --suite minimal --range-begin 5 --range-end 17
+          python3 run_suite.py --suite minimal --range-begin 4 --range-end 14
 
   unit-test-backend-part-3:
     if: github.repository == 'sgl-project/sglang' || github.event_name == 'pull_request'
@@ -84,7 +84,7 @@ jobs:
         timeout-minutes: 20
         run: |
           cd test/srt
-          python3 run_suite.py --suite minimal --range-begin 17 --range-end 20
+          python3 run_suite.py --suite minimal --range-begin 14 --range-end 20
 
   unit-test-backend-part-4:
     if: github.repository == 'sgl-project/sglang' || github.event_name == 'pull_request'

docs/hyperparameter_tuning.md

 # Guide on Hyperparameter Tuning
 
 ## Achieving Peak Throughput
-
 Achieving a large batch size is the most important thing for attaining high throughput.
 
 When the server is running at full load, look for the following in the log:

python/sglang/srt/managers/schedule_batch.py

@@ -221,7 +221,7 @@ class Req:
         self.prefix_indices = []
         self.extend_input_len = 0
         self.last_node = None
-        self.is_inflight_req = 0
+        self.is_being_chunked = 0
 
         # Logprobs (arguments)
         self.return_logprob = False
@@ -888,7 +888,7 @@ class ScheduleBatch:
 
     def filter_batch(
         self,
-        current_inflight_req: Optional[Req] = None,
+        being_chunked_req: Optional[Req] = None,
         keep_indices: Optional[List[int]] = None,
     ):
         if keep_indices is None:
@@ -896,7 +896,7 @@ class ScheduleBatch:
                 i
                 for i in range(len(self.reqs))
                 if not self.reqs[i].finished()
-                and self.reqs[i] is not current_inflight_req
+                and self.reqs[i] is not being_chunked_req
             ]
 
         if keep_indices is None or len(keep_indices) == 0:

python/sglang/srt/managers/scheduler.py

@@ -231,7 +231,7 @@ class Scheduler:
 
         # Init chunked prefill
         self.chunked_prefill_size = server_args.chunked_prefill_size
-        self.current_inflight_req = None
+        self.being_chunked_req = None
         self.is_mixed_chunk = (
             self.chunked_prefill_size is not None and server_args.enable_mixed_chunk
         )
@@ -551,13 +551,13 @@ class Scheduler:
             and not self.last_batch.forward_mode.is_decode()
             and not self.last_batch.is_empty()
         ):
-            if self.current_inflight_req:
+            if self.being_chunked_req:
                 self.last_batch.filter_batch(
-                    current_inflight_req=self.current_inflight_req
+                    being_chunked_req=self.being_chunked_req
                 )
-                self.tree_cache.cache_unfinished_req(self.current_inflight_req)
+                self.tree_cache.cache_unfinished_req(self.being_chunked_req)
                 # Inflight request keeps its rid but will get a new req_pool_idx.
-                self.req_to_token_pool.free(self.current_inflight_req.req_pool_idx)
+                self.req_to_token_pool.free(self.being_chunked_req.req_pool_idx)
                 self.batch_is_full = False
             if not self.last_batch.is_empty():
                 if self.running_batch is None:
@@ -588,7 +588,7 @@ class Scheduler:
         # Handle the cases where prefill is not allowed
         if (
             self.batch_is_full or len(self.waiting_queue) == 0
-        ) and self.current_inflight_req is None:
+        ) and self.being_chunked_req is None:
             return None
 
         running_bs = len(self.running_batch.reqs) if self.running_batch else 0
@@ -611,13 +611,11 @@ class Scheduler:
             num_mixed_running,
         )
 
-        has_inflight = self.current_inflight_req is not None
+        has_inflight = self.being_chunked_req is not None
         if has_inflight:
-            self.current_inflight_req.init_next_round_input(
-                None if prefix_computed else self.tree_cache
-            )
-            self.current_inflight_req = adder.add_inflight_req(
-                self.current_inflight_req
+            self.being_chunked_req.init_next_round_input()
+            self.being_chunked_req = adder.add_inflight_req(
+                self.being_chunked_req
             )
 
         if self.lora_paths:
@@ -661,11 +659,11 @@ class Scheduler:
         ]
 
         if adder.new_inflight_req is not None:
-            assert self.current_inflight_req is None
-            self.current_inflight_req = adder.new_inflight_req
+            assert self.being_chunked_req is None
+            self.being_chunked_req = adder.new_inflight_req
 
-        if self.current_inflight_req:
-            self.current_inflight_req.is_inflight_req += 1
+        if self.being_chunked_req:
+            self.being_chunked_req.is_being_chunked += 1
 
         # Print stats
         if self.tp_rank == 0:
@@ -833,8 +831,8 @@ class Scheduler:
             # Check finish conditions
             logprob_pt = 0
             for i, req in enumerate(batch.reqs):
-                if req.is_inflight_req > 0:
-                    req.is_inflight_req -= 1
+                if req.is_being_chunked > 0:
+                    req.is_being_chunked -= 1
                 else:
                     # Inflight reqs' prefill is not finished
                     req.completion_tokens_wo_jump_forward += 1
@@ -860,8 +858,8 @@ class Scheduler:
             # Check finish conditions
             for i, req in enumerate(batch.reqs):
                 req.embedding = embeddings[i]
-                if req.is_inflight_req > 0:
-                    req.is_inflight_req -= 1
+                if req.is_being_chunked > 0:
+                    req.is_being_chunked -= 1
                 else:
                     # Inflight reqs' prefill is not finished
                     # dummy output token for embedding models

scripts/killall_sglang.sh

-"""
-Kill all SGLang processes and free the GPU memory.
-"""
+# Kill all SGLang processes and free the GPU memory.
 
 kill -9 $(ps aux | grep 'multiprocessing.spawn' | grep -v 'grep' | awk '{print $2}')
 kill -9 $(ps aux | grep 'sglang.launch_server' | grep -v 'grep' | awk '{print $2}')

test/srt/run_suite.py

@@ -19,6 +19,7 @@ suites = {
         "test_openai_server.py",
         "test_overlap_schedule.py",
         "test_pytorch_sampling_backend.py",
+        "test_radix_attention.py",
         "test_retract_decode.py",
         "test_server_args.py",
         "test_skip_tokenizer_init.py",

test/srt/test_radix_attention.py

+import os
+import random
+import unittest
+
+import requests
+
+from sglang.test.test_utils import (
+    DEFAULT_MODEL_NAME_FOR_TEST,
+    DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
+    DEFAULT_URL_FOR_TEST,
+    kill_child_process,
+    popen_launch_server,
+)
+
+
+def gen_radix_tree(num_nodes=400, chunk_len=256):
+    num0 = num_nodes // 2
+    num1 = num_nodes - num0
+    nodes = [{"input_ids": [37] * 117, "decode_len": 217}]
+    for _ in range(num0):
+        parent = random.choice(nodes)
+        unique_len = random.randint(0, chunk_len)
+        decode_len = random.randint(0, chunk_len)
+        token_id = random.randint(0, 32000)
+        child = {
+            "input_ids": parent["input_ids"] + [token_id] * unique_len,
+            "decode_len": decode_len,
+        }
+        nodes.append(child)
+
+    while num1 > 0:
+        num_branch = random.randint(1, min(num1, 10))
+        parent = random.choice(nodes)
+        for _ in range(num_branch):
+            unique_len = random.randint(0, chunk_len)
+            decode_len = random.randint(0, chunk_len)
+            token_id = random.randint(0, 32000)
+            child = {
+                "input_ids": parent["input_ids"] + [token_id] * unique_len,
+                "decode_len": decode_len,
+            }
+            nodes.append(child)
+
+        num1 -= num_branch
+
+    random.shuffle(nodes)
+    return nodes
+
+
+def run_test(base_url, nodes):
+    data = {
+        "input_ids": [node["input_ids"] for node in nodes],
+        "sampling_params": [
+            {"max_new_tokens": node["decode_len"], "temperature": 0} for node in nodes
+        ],
+    }
+
+    res = requests.post(base_url + "/generate", json=data)
+    assert res.status_code == 200
+
+
+class TestRadixCacheFCFS(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        cls.model = DEFAULT_MODEL_NAME_FOR_TEST
+        cls.base_url = DEFAULT_URL_FOR_TEST
+        cls.process = popen_launch_server(
+            cls.model,
+            cls.base_url,
+            timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
+            other_args=[
+                "--chunked-prefill-size",
+                "128",
+                "--max-total-tokens",
+                "20000",
+                "--schedule-policy",
+                "fcfs",
+            ],
+        )
+
+    @classmethod
+    def tearDownClass(cls):
+        kill_child_process(cls.process.pid, include_self=True)
+
+    def test_radix_attention(self):
+        nodes = gen_radix_tree()
+        run_test(self.base_url, nodes)
+
+
+class TestRadixCacheLPM(TestRadixCacheFCFS):
+    @classmethod
+    def setUpClass(cls):
+        cls.model = DEFAULT_MODEL_NAME_FOR_TEST
+        cls.base_url = DEFAULT_URL_FOR_TEST
+        cls.process = popen_launch_server(
+            cls.model,
+            cls.base_url,
+            timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
+            other_args=[
+                "--chunked-prefill-size",
+                "128",
+                "--max-total-tokens",
+                "20000",
+                "--schedule-policy",
+                "lpm",
+            ],
+        )
+
+
+if __name__ == "__main__":
+    os.environ["SGLANG_TEST_RETRACT"] = "true"
+    unittest.main()