[Misc] Replace CUDA_VISIBLE_DEVICES in DP with torch.cuda.set_device for device selection on cuda-like devices (#27564)

Signed-off-by: ilmarkov <markovilya197@gmail.com>
Co-authored-by: Tyler Michael Smith <tlrmchlsmth@gmail.com>

vllm/v1/engine/utils.py

@@ -134,9 +134,18 @@ class CoreEngineProcManager:
         data_parallel = vllm_config.parallel_config.data_parallel_size > 1
         try:
             for proc, local_dp_rank in zip(self.processes, local_dp_ranks):
+                # Adjust device control in DP for non-CUDA platforms
+                # as well as external and ray launchers
+                # For CUDA platforms, we use torch.cuda.set_device()
                 with (
                     set_device_control_env_var(vllm_config, local_dp_rank)
-                    if (data_parallel)
+                    if (
+                        data_parallel
+                        and (
+                            not current_platform.is_cuda_alike()
+                            or vllm_config.parallel_config.use_ray
+                        )
+                    )
                     else contextlib.nullcontext()
                 ):
                     proc.start()