[Bugfix] Restrict TRTLLM attention to SM100, fixing GB300 (SM103) hang (#38730)

Signed-off-by: Stefano Castagnetta <scastagnetta@nvidia.com>
(cherry picked from commit 6183cae1)

docs/design/attention_backends.md

@@ -167,7 +167,7 @@ Priority is **1 = highest** (tried first).
 | ------- | ------- | ------ | --------- | ----------- | ---------- | ---- | --------- | --- | --------------- | ------------ |
 | `CPU_ATTN` | | fp16, bf16, fp32 | `auto` | Any | 32, 64, 80, 96, 112, 128, 160, 192, 224, 256 | ❌ | ❌ | ❌ | All | N/A |
 | `FLASHINFER` | Native† | fp16, bf16 | `auto`, `float16`, `bfloat16`, `fp8`, `fp8_e4m3`, `fp8_e5m2` | 16, 32, 64 | 64, 128, 256 | ❌ | ❌ | ✅ | Decoder | 7.x-9.x |
-| `FLASHINFER` | TRTLLM† | fp16, bf16 | `auto`, `float16`, `bfloat16`, `fp8`, `fp8_e4m3`, `fp8_e5m2` | 16, 32, 64 | 64, 128, 256 | ✅ | ❌ | ✅ | Decoder | 10.x |
+| `FLASHINFER` | TRTLLM† | fp16, bf16 | `auto`, `float16`, `bfloat16`, `fp8`, `fp8_e4m3`, `fp8_e5m2` | 16, 32, 64 | 64, 128, 256 | ✅ | ❌ | ✅ | Decoder | 10.0 |
 | `FLASH_ATTN` | FA2* | fp16, bf16 | `auto`, `float16`, `bfloat16` | %16 | Any | ❌ | ❌ | ✅ | All | ≥8.0 |
 | `FLASH_ATTN` | FA3* | fp16, bf16 | `auto`, `float16`, `bfloat16`, `fp8`, `fp8_e4m3`, `fp8_e5m2` | %16 | Any | ✅ | ❌ | ✅ | All | 9.x |
 | `FLASH_ATTN` | FA4* | fp16, bf16 | `auto`, `float16`, `bfloat16` | %16 | Any | ❌ | ❌ | ✅ | All | ≥10.0 |

tools/pre_commit/generate_attention_backend_docs.py

@@ -235,10 +235,11 @@ def _resolve_import_to_file(
 
 
 def _find_cc_in_function(tree: ast.AST, func_name: str) -> str | None:
-    """Find a compute capability from is_device_capability_family() calls in a function.
+    """Find a compute capability from is_device_capability*() calls in a function.
 
-    Looks for the pattern: current_platform.is_device_capability_family(N)
-    and converts N (e.g. 100) to a CC string (e.g. "10.x").
+    Handles two patterns:
+    - is_device_capability_family(N): "M.x" (e.g. 100 -> "10.x")
+    - is_device_capability(N): "M.m" (e.g. 100 -> "10.0")
     """
     for node in ast.walk(tree):
         if not isinstance(node, ast.FunctionDef) or node.name != func_name:
@@ -247,12 +248,15 @@ def _find_cc_in_function(tree: ast.AST, func_name: str) -> str | None:
             if (
                 isinstance(n, ast.Call)
                 and isinstance(n.func, ast.Attribute)
-                and n.func.attr == "is_device_capability_family"
                 and n.args
                 and isinstance(n.args[0], ast.Constant)
                 and isinstance(n.args[0].value, int)
             ):
-                return f"{n.args[0].value // 10}.x"
+                val = n.args[0].value
+                if n.func.attr == "is_device_capability_family":
+                    return f"{val // 10}.x"
+                elif n.func.attr == "is_device_capability":
+                    return f"{val // 10}.{val % 10}"
     return None
 
 

vllm/utils/flashinfer.py

@@ -289,10 +289,10 @@ def supports_trtllm_attention() -> bool:
     if envs.VLLM_BATCH_INVARIANT:
         return False
 
-    # Requires SM100 and NVIDIA artifactory to be accessible to download cubins
-    return (
-        current_platform.is_device_capability_family(100) and has_nvidia_artifactory()
-    )
+    # TRTLLM attention is currently only validated on SM100 (CC 10.0).
+    # SM103 (GB300) hangs with FlashInfer >= 0.6.7.
+    # See: https://github.com/flashinfer-ai/flashinfer/issues/2939
+    return current_platform.is_device_capability(100) and has_nvidia_artifactory()
 
 
 def force_use_trtllm_attention() -> bool | None: