diff --git a/docs/docs/advanced_features/server_arguments.mdx b/docs/docs/advanced_features/server_arguments.mdx
index 698ef417d..eea2a0768 100644
--- a/docs/docs/advanced_features/server_arguments.mdx
+++ b/docs/docs/advanced_features/server_arguments.mdx
@@ -312,6 +312,12 @@ Please consult the documentation below and [server_args.py](https://github.com/s
| `False` |
bool flag (set to enable) |
+
+ | `--http2-max-concurrent-streams` |
+ Maximum number of concurrent streams advertised on each HTTP/2 connection (1 to 2^32 - 1). Only applies with --enable-http2. |
+ `200` |
+ Type: int |
+
diff --git a/python/sglang/srt/entrypoints/http_server.py b/python/sglang/srt/entrypoints/http_server.py
index 5aa6fcca1..3371fcf0a 100644
--- a/python/sglang/srt/entrypoints/http_server.py
+++ b/python/sglang/srt/entrypoints/http_server.py
@@ -2392,6 +2392,7 @@ def _run_granian_server(
host,
port,
log_level,
+ http2_max_concurrent_streams,
tokenizer_worker_num=1,
ssl_certfile=None,
ssl_keyfile=None,
@@ -2415,6 +2416,7 @@ def _run_granian_server(
from granian import Granian
from granian.constants import HTTPModes, Interfaces, Loops
+ from granian.http import HTTP2Settings
from granian.server.embed import Server as GranianEmbeddedServer
Server = GranianEmbeddedServer if tokenizer_worker_num == 1 else Granian
@@ -2427,6 +2429,9 @@ def _run_granian_server(
port=port,
interface=Interfaces.ASGI,
http=HTTPModes.auto,
+ http2_settings=HTTP2Settings(
+ max_concurrent_streams=http2_max_concurrent_streams
+ ),
log_level=log_level,
ssl_cert=ssl_certfile,
ssl_key=ssl_keyfile,
@@ -2556,6 +2561,9 @@ def _setup_and_run_http_server(
host=server_args.host,
port=server_args.port,
log_level=server_args.log_level_http or server_args.log_level,
+ http2_max_concurrent_streams=(
+ server_args.http2_max_concurrent_streams
+ ),
ssl_certfile=server_args.ssl_certfile,
ssl_keyfile=server_args.ssl_keyfile,
ssl_ca_certs=server_args.ssl_ca_certs,
@@ -2640,6 +2648,9 @@ def _setup_and_run_http_server(
host=server_args.host,
port=server_args.port,
log_level=server_args.log_level_http or server_args.log_level,
+ http2_max_concurrent_streams=(
+ server_args.http2_max_concurrent_streams
+ ),
tokenizer_worker_num=server_args.tokenizer_worker_num,
ssl_certfile=server_args.ssl_certfile,
ssl_keyfile=server_args.ssl_keyfile,
diff --git a/python/sglang/srt/server_args.py b/python/sglang/srt/server_args.py
index 0eca8eee2..d7c0c15ab 100644
--- a/python/sglang/srt/server_args.py
+++ b/python/sglang/srt/server_args.py
@@ -1306,6 +1306,12 @@ class ServerArgs:
"Use Granian instead of Uvicorn as the ASGI server, enabling HTTP/1.1 and HTTP/2 auto-negotiation. Clients may use h2c (cleartext HTTP/2) or plain HTTP/1.1. Requires 'pip install sglang[http2]'.",
NS("serving"),
] = False
+ http2_max_concurrent_streams: A[
+ int,
+ "Maximum number of concurrent streams advertised on each HTTP/2 "
+ "connection (1 to 2^32 - 1). Only applies with --enable-http2.",
+ NS("serving"),
+ ] = 200
# -------------------------------------------------------------------------
# SSL/TLS
@@ -4029,6 +4035,12 @@ class ServerArgs:
)
if self.enable_http2:
+ if not 0 < self.http2_max_concurrent_streams < 2**32:
+ raise ValueError(
+ "--http2-max-concurrent-streams must be between 1 and "
+ "4294967295."
+ )
+
try:
import granian # noqa: F401
except ImportError:
diff --git a/test/registered/openai_server/basic/test_http2_server.py b/test/registered/openai_server/basic/test_http2_server.py
index e90580b49..db0ceddfb 100644
--- a/test/registered/openai_server/basic/test_http2_server.py
+++ b/test/registered/openai_server/basic/test_http2_server.py
@@ -41,7 +41,11 @@ class TestHTTP2Server(CustomTestCase):
cls.model,
cls.base_url,
timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
- other_args=["--enable-http2"],
+ other_args=[
+ "--enable-http2",
+ "--http2-max-concurrent-streams",
+ "64",
+ ],
)
@classmethod
@@ -126,7 +130,13 @@ class TestHTTP2ServerMultiTokenizer(TestHTTP2Server):
cls.model,
cls.base_url,
timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
- other_args=["--enable-http2", "--tokenizer-worker-num", "2"],
+ other_args=[
+ "--enable-http2",
+ "--http2-max-concurrent-streams",
+ "64",
+ "--tokenizer-worker-num",
+ "2",
+ ],
)
diff --git a/test/registered/unit/entrypoints/test_http2_server_config.py b/test/registered/unit/entrypoints/test_http2_server_config.py
new file mode 100644
index 000000000..b3881a686
--- /dev/null
+++ b/test/registered/unit/entrypoints/test_http2_server_config.py
@@ -0,0 +1,40 @@
+import importlib.util
+import unittest
+from unittest.mock import patch
+
+from sglang.srt.entrypoints.http_server import _run_granian_server
+from sglang.test.ci.ci_register import register_cpu_ci
+
+register_cpu_ci(est_time=2, suite="base-a-test-cpu")
+
+
+@unittest.skipUnless(
+ importlib.util.find_spec("granian"), "granian is required for HTTP/2"
+)
+class TestGranianHTTP2Config(unittest.TestCase):
+ def test_passes_explicit_max_concurrent_streams(self):
+ configured = {}
+
+ class FakeEmbeddedServer:
+ def __init__(self, **kwargs):
+ configured.update(kwargs)
+
+ async def serve(self):
+ return None
+
+ def stop(self):
+ return None
+
+ with patch("granian.server.embed.Server", FakeEmbeddedServer):
+ _run_granian_server(
+ host="127.0.0.1",
+ port=30000,
+ log_level="info",
+ http2_max_concurrent_streams=37,
+ )
+
+ self.assertEqual(configured["http2_settings"].max_concurrent_streams, 37)
+
+
+if __name__ == "__main__":
+ unittest.main()