[Bugfix] Fix FA3 full cuda graph correctness (#19106)

Signed-off-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>

tests/compile/piecewise/test_full_cudagraph.py

@@ -7,6 +7,7 @@ import pytest
 
 from vllm import LLM, SamplingParams
 from vllm.config import CompilationConfig
+from vllm.platforms import current_platform
 
 MODEL = "Qwen/Qwen2-1.5B-Instruct"
 
@@ -37,7 +38,7 @@ def full_cudagraph_llm():
             "VLLM_FLASH_ATTN_VERSION": "3"
     }):
         return LLM(model=MODEL,
-                   gpu_memory_utilization=0.2,
+                   gpu_memory_utilization=0.3,
                    compilation_config=CompilationConfig(full_cuda_graph=True))
 
 
@@ -48,7 +49,7 @@ def piecewise_llm():
             "VLLM_FLASH_ATTN_VERSION": "3"
     }):
         return LLM(model=MODEL,
-                   gpu_memory_utilization=0.5,
+                   gpu_memory_utilization=0.6,
                    compilation_config=CompilationConfig())
 
 
@@ -61,6 +62,8 @@ def generate_text(llm: LLM, batch_size: int, max_tokens: int):
     return llm.generate(prompts, sampling_params)
 
 
+@pytest.mark.skipif(current_platform.get_device_capability() != (9, 0),
+                    reason="Only Hopper GPUs support FlashAttention 3")
 @pytest.mark.parametrize(("batch_size", "max_tokens"), [(1, 10), (7, 10),
                                                         (16, 10), (25, 10),
                                                         (32, 10), (45, 10),