[Bugfix] Fix multi nodes TP+PP for XPU (vllm-project#8884)

Signed-off-by: YiSheng5 <syhm@mail.ustc.edu.cn>
Signed-off-by: yan ma <yan.ma@intel.com>
Co-authored-by: YiSheng5 <syhm@mail.ustc.edu.cn>
Signed-off-by: NickLucche <nlucches@redhat.com>

docs/source/getting_started/xpu-installation.rst

@@ -60,3 +60,21 @@ Build from source
     - FP16 is the default data type in the current XPU backend. The BF16 data
       type will be supported in the future.
 
+
+Distributed inference and serving
+---------------------------------
+
+XPU platform supports tensor-parallel inference/serving and also supports pipeline parallel as a beta feature for online serving. We requires Ray as the distributed runtime backend. For example, a reference execution likes following:
+
+.. code-block:: console
+
+    $ python -m vllm.entrypoints.openai.api_server \
+    $      --model=facebook/opt-13b \
+    $      --dtype=bfloat16 \
+    $      --device=xpu \
+    $      --max_model_len=1024 \
+    $      --distributed-executor-backend=ray \
+    $      --pipeline-parallel-size=2 \
+    $      -tp=8
+
+By default, a ray instance will be launched automatically if no existing one is detected in system, with ``num-gpus`` equals to ``parallel_config.world_size``. We recommend properly starting a ray cluster before execution, referring helper `script <https://github.com/vllm-project/vllm/tree/main/examples/run_cluster.sh>`_.

requirements-xpu.txt

@@ -13,4 +13,4 @@ torch == 2.3.1+cxx11.abi
 intel-extension-for-pytorch == 2.3.110+xpu
 oneccl_bind_pt == 2.3.100+xpu
 
-triton-xpu == 3.0.0b2
+triton-xpu == 3.0.0b1

vllm/distributed/parallel_state.py

@@ -431,6 +431,28 @@ def gather(self,
         if dim < 0:
             # Convert negative dim to positive.
             dim += input_.dim()
+        # For xpu path, gather doesn't work properly together with ray
+        # cluster so we use all_gather instead for now.
+        if current_platform.is_xpu():
+            input_size = input_.size()
+            # Allocate output tensor.
+            output_tensor = torch.empty((world_size, ) + input_size,
+                                        dtype=input_.dtype,
+                                        device=input_.device)
+            # All-gather.
+            torch.distributed.all_gather_into_tensor(output_tensor,
+                                                     input_,
+                                                     group=self.device_group)
+            if self.rank_in_group == dst:
+                # Reshape
+                output_tensor = output_tensor.movedim(0, dim)
+                output_tensor = output_tensor.reshape(input_size[:dim] +
+                                                      (world_size *
+                                                       input_size[dim], ) +
+                                                      input_size[dim + 1:])
+            else:
+                output_tensor = None
+            return output_tensor
         # Allocate output tensor.
         if self.rank_in_group == dst:
             gather_list = [torch.empty_like(input_) for _ in range(world_size)]

vllm/executor/xpu_executor.py

@@ -44,7 +44,7 @@ def __init__(
         self.cache_config = cache_config
         self.load_config = load_config
         self.lora_config = lora_config
-        self.parallel_config = parallel_config
+        self.parallel_config = _verify_and_get_parallel_config(parallel_config)
         self.scheduler_config = scheduler_config
         self.device_config = device_config
         self.prompt_adapter_config = prompt_adapter_config
@@ -94,3 +94,13 @@ def _verify_and_get_model_config(config: ModelConfig) -> ModelConfig:
             "mode.")
         config.enforce_eager = True
     return config
+
+
+def _verify_and_get_parallel_config(config: ParallelConfig) -> ParallelConfig:
+    if (config.distributed_executor_backend is not None
+            and config.distributed_executor_backend != "ray"):
+        logger.warning(
+            "%s is not supported on XPU, fallback to ray distributed executor "
+            "backend.", config.distributed_executor_backend)
+        config.distributed_executor_backend = "ray"
+    return config

vllm/platforms/__init__.py

@@ -45,6 +45,9 @@
 is_xpu = False
 
 try:
+    # installed IPEX if the machine has XPUs.
+    import intel_extension_for_pytorch  # noqa: F401
+    import oneccl_bindings_for_pytorch  # noqa: F401
     import torch
     if hasattr(torch, 'xpu') and torch.xpu.is_available():
         is_xpu = True

vllm/platforms/xpu.py

@@ -20,3 +20,7 @@ def get_device_name(device_id: int = 0) -> str:
     def get_device_total_memory(cls, device_id: int = 0) -> int:
         device_props = torch.xpu.get_device_properties(device_id)
         return device_props.total_memory
+
+    @staticmethod
+    def inference_mode():
+        return torch.no_grad()

vllm/worker/xpu_worker.py

@@ -14,7 +14,6 @@
                          SpeculativeConfig)
 from vllm.distributed import (ensure_model_parallel_initialized,
                               init_distributed_environment)
-from vllm.distributed.parallel_state import get_pp_group
 from vllm.logger import init_logger
 from vllm.model_executor import set_random_seed
 from vllm.platforms import current_platform
@@ -183,11 +182,10 @@ def init_worker_distributed_environment(self) -> None:
             # use sockets as default Level zero IPC exchange backend. By
             # default oneccl will use `drmfd` as mechanism which need extra
             # dependency (libdrm and drm headers) on your system.
-            ENV_CCL_ZE_IPC_EXCHANGE = os.getenv("CCL_ZE_IPC_EXCHANGE",
-                                                "sockets")
+            ENV_CCL_ATL_TRANSPORT = os.getenv("CCL_ATL_TRANSPORT", "ofi")
             ENV_LOCAL_WORLD_SIZE = os.getenv("LOCAL_WORLD_SIZE",
                                              str(parallel_config.world_size))
-            os.environ['CCL_ZE_IPC_EXCHANGE'] = ENV_CCL_ZE_IPC_EXCHANGE
+            os.environ["CCL_ATL_TRANSPORT"] = ENV_CCL_ATL_TRANSPORT
             os.environ["LOCAL_WORLD_SIZE"] = ENV_LOCAL_WORLD_SIZE
             os.environ["LOCAL_RANK"] = str(self.local_rank)
             init_distributed_environment(
@@ -200,8 +198,5 @@ def init_worker_distributed_environment(self) -> None:
         ensure_model_parallel_initialized(
             parallel_config.tensor_parallel_size,
             parallel_config.pipeline_parallel_size)
-
-        if parallel_config.pipeline_parallel_size > 1:
-            # torch-ccl xpu need a collective API warm up
-            # before calling send/recv API
-            get_pp_group().all_reduce(torch.zeros(1).xpu())
+        # global all_reduce needed for overall oneccl warm up
+        torch.distributed.all_reduce(torch.zeros(1).xpu())