[Disaggregated Prefill] P2P Disaggregated Prefill based on llm_datadist (#694)

### What this PR does / why we need it?
- This PR proposes a P2P version of Disaggregated Prefill based on
llm_datadist which manages data transfer.

- This solution reconstructs previous offline single-node Disaggregated
Prefill solution, and supports multi-node and online serveing now.

- Currently this solution supports 1P1D situation of Deepseek hybrid
parallelism (P: TP+EP, D: DP+EP). Note that xPyD situation is considered
in the solution design, and will be supported soon within v1 engine.

---------

Signed-off-by: hw_whx <wanghexiang7@huawei.com>
Signed-off-by: ganyi <pleaplusone.gy@gmail.com>
Co-authored-by: hw_whx <wanghexiang7@huawei.com>
Co-authored-by: ganyi <pleaplusone.gy@gmail.com>

examples/disaggregated_prefill/find_device_ips.py

@@ -0,0 +1,67 @@
+#
+# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
+# Copyright 2023 The vLLM team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# This file is a part of the vllm-ascend project.
+# Adapted from vllm-project/vllm/examples/offline_inference/basic.py
+#
+"""
+ This file provides a function to obtain ips of all NPU Devices in current machine.
+"""
+
+import os
+import re
+import subprocess
+
+import vllm_ascend.envs as envs
+
+# Get all device ips using hccn_tool
+HCCN_TOOL_PATH = envs.HCCN_PATH
+
+
+def get_device_ips(world_size: int):
+    npu_info = subprocess.run(
+        ["npu-smi", "info", "-m"],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        universal_newlines=True,
+    )
+    if npu_info.returncode != 0 or not os.path.exists(HCCN_TOOL_PATH):
+        raise RuntimeError("No npu-smi/hccn_tool tools provided for NPU.")
+    npu_start_idx = int(
+        re.match(r".*\n\t([0-9]+).*",
+                 npu_info.stdout).group(1))  # type: ignore
+    device_ip_list = []
+    for ip_offset in range(world_size):
+        cmd = [
+            HCCN_TOOL_PATH,
+            "-i",
+            f"{npu_start_idx + ip_offset}",
+            "-ip",
+            "-g",
+        ]
+        device_ip_info = subprocess.run(
+            cmd,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            universal_newlines=True,
+        )
+        device_ip = re.match(r"ipaddr:(.*)\n",
+                             device_ip_info.stdout).group(1)  # type: ignore
+        device_ip_list.append(device_ip)
+    return device_ip_list
+
+
+# Pass number of NPUs into this function.
+print(get_device_ips(8))