[Perf] Change default CUDAGraphMode from FULL_AND_PIECEWISE to PIECEWISE

vllm/config/compilation.py

@@ -78,7 +78,7 @@ class CUDAGraphMode(enum.Enum):
         return self.has_mode(CUDAGraphMode.PIECEWISE)
 
     def max_cudagraph_mode(self) -> "CUDAGraphMode":
-        return CUDAGraphMode(max(self.value) if not envs.VLLM_USE_PIECEWISE else min(self.value)) if self.separate_routine() else self
+        return CUDAGraphMode(max(self.value)) if self.separate_routine() else self
 
     def has_full_cudagraphs(self) -> bool:
         return self.max_cudagraph_mode() == CUDAGraphMode.FULL

vllm/config/vllm.py

@@ -694,6 +694,7 @@ class VllmConfig:
         if current_platform.support_static_graph_mode():
             # if cudagraph_mode has full cudagraphs, we need to check support
             if model_config := self.model_config:
+                if not envs.VLLM_USE_PIECEWISE:
                     if (
                         self.compilation_config.cudagraph_mode.has_full_cudagraphs()
                         and model_config.pooler_config is not None
@@ -716,6 +717,8 @@ class VllmConfig:
                         self.compilation_config.cudagraph_mode = (
                             CUDAGraphMode.FULL_DECODE_ONLY
                         )
+                else:
+                    self.compilation_config.cudagraph_mode = CUDAGraphMode.PIECEWISE
 
             # disable cudagraph when enforce eager execution
             if self.model_config is not None and self.model_config.enforce_eager:

vllm/v1/worker/gpu_model_runner.py

@@ -4109,7 +4109,11 @@ class GPUModelRunner(
                 # TODO(luka) better system for describing dummy batches
                 seq_lens = [1] * num_decode_tokens + [num_prefill_tokens + 1]
             else:
-                seq_lens = max_query_len  # type: ignore[assignment]
+                if not envs.VLLM_USE_PIECEWISE:
+                    seq_lens = max_query_len
+                else:
+                    # Make sure max_model_len is used at the graph capture time.
+                    seq_lens = self.max_model_len
             self.seq_lens.np[:num_reqs] = seq_lens
             self.seq_lens.np[num_reqs:] = 0
             self.seq_lens.copy_to_gpu()
@@ -4825,6 +4829,7 @@ class GPUModelRunner(
             logger.warning(msg)
 
         # check that if we are doing decode full-cudagraphs it is supported
+        if not envs.VLLM_USE_PIECEWISE:
             if (
                 cudagraph_mode.decode_mode() == CUDAGraphMode.FULL
                 and min_cg_support == AttentionCGSupport.NEVER