[Bug] Temporally Disable VLLM_ALLREDUCE_USE_SYMM_MEM by Default (vllm-project#26925)

Signed-off-by: yewentao256 <zhyanwentao@126.com>
Signed-off-by: Alberto Perdomo <aperdomo@redhat.com>

Author: yewentao256

vllm/envs.py

@@ -198,7 +198,7 @@
     VLLM_USE_FLASHINFER_MOE_MXFP4_BF16: bool = False
     VLLM_ROCM_FP8_MFMA_PAGE_ATTN: bool = False
     VLLM_USE_FLASHINFER_MOE_MXFP4_MXFP8_CUTLASS: bool = False
-    VLLM_ALLREDUCE_USE_SYMM_MEM: bool = True
+    VLLM_ALLREDUCE_USE_SYMM_MEM: bool = False
     VLLM_TUNED_CONFIG_FOLDER: str | None = None
     VLLM_GPT_OSS_HARMONY_SYSTEM_INSTRUCTIONS: bool = False
     VLLM_CUSTOM_SCOPES_FOR_PROFILING: bool = False
@@ -1343,7 +1343,7 @@ def get_vllm_port() -> int | None:
     ),
     # Whether to use pytorch symmetric memory for allreduce
     "VLLM_ALLREDUCE_USE_SYMM_MEM": lambda: bool(
-        int(os.getenv("VLLM_ALLREDUCE_USE_SYMM_MEM", "1"))
+        int(os.getenv("VLLM_ALLREDUCE_USE_SYMM_MEM", "0"))
     ),
     # Allows vllm to find tuned config under customized folder
     "VLLM_TUNED_CONFIG_FOLDER": lambda: os.getenv("VLLM_TUNED_CONFIG_FOLDER", None),