[#16330][fix] Gate PDL on supported GPU architectures

tensorrt_llm/_torch/flashinfer_utils.py

@@ -1,16 +1,41 @@
+# SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+#
+# 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.
+
 import os
 import platform
 import traceback
 
+from .._utils import get_sm_version
 from ..logger import logger
 
 IS_FLASHINFER_AVAILABLE = False
 
 
 def get_env_enable_pdl() -> bool:
-    enabled = os.environ.get("TRTLLM_ENABLE_PDL", "1") == "1"
-    if enabled and not getattr(get_env_enable_pdl, "_printed", False):
-        logger.info("PDL enabled")
+    requested = os.environ.get("TRTLLM_ENABLE_PDL", "1") == "1"
+    if not requested:
+        return False
+
+    sm_version = get_sm_version()
+    enabled = sm_version >= 90
+    if not getattr(get_env_enable_pdl, "_printed", False):
+        if enabled:
+            logger.info("PDL enabled")
+        else:
+            logger.info(
+                f"PDL disabled on SM{sm_version}: requires SM90 or newer")
         setattr(get_env_enable_pdl, "_printed", True)
     return enabled
 

tests/unittest/_torch/test_flashinfer_utils.py

@@ -0,0 +1,41 @@
+# SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+#
+# 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.
+
+import pytest
+
+from tensorrt_llm._torch import flashinfer_utils
+
+
+@pytest.mark.parametrize(
+    ("env_value", "sm_version", "expected"),
+    [
+        (None, 89, False),
+        ("1", 89, False),
+        ("0", 89, False),
+        (None, 90, True),
+        ("1", 90, True),
+        ("0", 90, False),
+        (None, 100, True),
+    ],
+)
+def test_get_env_enable_pdl_hardware_gate(monkeypatch, env_value, sm_version, expected):
+    if env_value is None:
+        monkeypatch.delenv("TRTLLM_ENABLE_PDL", raising=False)
+    else:
+        monkeypatch.setenv("TRTLLM_ENABLE_PDL", env_value)
+    monkeypatch.setattr(flashinfer_utils, "get_sm_version", lambda: sm_version)
+    monkeypatch.delattr(flashinfer_utils.get_env_enable_pdl, "_printed", raising=False)
+
+    assert flashinfer_utils.get_env_enable_pdl() is expected