[BugFix] Fix data parallel (#940)

### What this PR does / why we need it?
With this PR, we can migrate to the native `data_parallel.py` in vllm
examples and remove the version in vllm-ascend.

At present, `ASCEND_RT_VISIBLE_DEVICES` introduces considerable
difficulties; therefore, we must employ a temporary workaround and
manually specify the device.

Signed-off-by: Yizhou Liu <liu_yizhou@outlook.com>

vllm_ascend/platform.py

@@ -18,10 +18,13 @@
 import gc
 import logging
 import os
+from datetime import timedelta
 from typing import TYPE_CHECKING, Optional, Tuple
 
 import torch
 import vllm.envs as envs
+from torch.distributed import ProcessGroup
+from torch.distributed.distributed_c10d import PrefixStore
 from vllm.logger import logger
 from vllm.platforms import Platform, PlatformEnum
 
@@ -262,3 +265,45 @@ class NPUPlatform(Platform):
         Get piecewise backend class for piecewise graph.
         """
         return "vllm_ascend.compilation.piecewise_backend.NPUPiecewiseBackend"  # noqa
+
+    @classmethod
+    def stateless_init_device_torch_dist_pg(
+        cls,
+        backend: str,
+        prefix_store: PrefixStore,
+        group_rank: int,
+        group_size: int,
+        timeout: timedelta,
+    ) -> ProcessGroup:
+        from torch.distributed import is_hccl_available
+        from torch_npu._C._distributed_c10d import ProcessGroupHCCL
+
+        assert is_hccl_available()
+
+        # TODO(Yizhou): The reason we need to set options while vllm does not
+        # seems to be related to the version of PyTorch. In the latest version,
+        # there is no need to set options. While in the older version, 2.5.1
+        # specifically, we need to set options.
+        options = ProcessGroup.Options(backend=backend)
+        pg: ProcessGroup = ProcessGroup(
+            prefix_store,
+            group_rank,
+            group_size,
+            options,
+        )
+
+        backend_options = ProcessGroupHCCL.Options()
+        backend_options._timeout = timeout
+
+        backend_class = ProcessGroupHCCL(prefix_store, group_rank, group_size,
+                                         backend_options)
+        device = torch.device("npu")
+        # TODO(Yizhou): Like we mentioned above, _set_default_backend is not
+        # implemented in the 2.5.1 version of PyTorch. But we need to set it
+        # after the latest version is released.
+        # pg._set_default_backend(backend_type)
+        backend_class._set_sequence_number_for_group()
+        backend_type = ProcessGroup.BackendType.CUSTOM
+
+        pg._register_backend(device, backend_type, backend_class)
+        return pg