chore: import upstream snapshot with attribution

tests/distributed/test_pp_cudagraph.py

@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+import pytest
+
+from vllm.platforms import current_platform
+
+from ..utils import compare_two_settings, create_new_process_for_each_test
+
+
+@pytest.mark.parametrize(
+    "PP_SIZE, MODEL_NAME",
+    [
+        (2, "JackFram/llama-160m"),
+    ],
+)
+@pytest.mark.parametrize(
+    "ATTN_BACKEND",
+    [None] if current_platform.is_rocm() else ["FLASH_ATTN"],
+)
+@create_new_process_for_each_test()
+def test_pp_cudagraph(
+    PP_SIZE: int,
+    MODEL_NAME: str,
+    ATTN_BACKEND: str | None,
+):
+    cudagraph_args = [
+        # use half precision for speed and memory savings in CI environment
+        "--dtype",
+        "float16",
+        "--pipeline-parallel-size",
+        str(PP_SIZE),
+        "--distributed-executor-backend",
+        "mp",
+    ]
+    # On ROCm, defer to the platform attention selector instead of forcing a backend.
+    if ATTN_BACKEND is not None:
+        cudagraph_args.append(f"--attention-backend={ATTN_BACKEND}")
+
+    eager_args = cudagraph_args + ["--enforce-eager"]
+
+    compare_two_settings(MODEL_NAME, eager_args, cudagraph_args)