[ci][distributed] add tests for custom allreduce (#5689)

Author: youkaichao

.buildkite/test-pipeline.yaml

@@ -182,7 +182,11 @@ steps:
   - pip install -r requirements-docs.txt
   - SPHINXOPTS=\"-W\" make html
 
-- label: A100 status
+- label: Distributed Tests (A100)
   gpu: a100
   commands: 
-  - nvidia-smi
+  # NOTE: don't test llama model here, it seems hf implementation is buggy
+  # see https://github.com/vllm-project/vllm/pull/5689 for details
+  - pytest -v -s distributed/test_custom_all_reduce.py
+  - TEST_DIST_MODEL=facebook/opt-125m DISTRIBUTED_EXECUTOR_BACKEND=ray pytest -v -s distributed/test_basic_distributed_correctness.py
+  - TEST_DIST_MODEL=facebook/opt-125m DISTRIBUTED_EXECUTOR_BACKEND=mp pytest -v -s distributed/test_basic_distributed_correctness.py

tests/distributed/test_custom_all_reduce.py

@@ -11,7 +11,8 @@
 from vllm.distributed.parallel_state import (get_tensor_model_parallel_group,
                                              get_tp_group, graph_capture)
 
-from ..utils import (init_test_distributed_environment,
+from ..utils import (ensure_model_parallel_initialized,
+                     init_test_distributed_environment,
                      multi_process_tensor_parallel)
 
 random.seed(42)
@@ -27,8 +28,8 @@ def graph_allreduce(tp_size, pp_size, rank, distributed_init_port):
     torch.cuda.set_device(device)
     init_test_distributed_environment(tp_size, pp_size, rank,
                                       distributed_init_port)
-
-    group = get_tensor_model_parallel_group()
+    ensure_model_parallel_initialized(tp_size, pp_size)
+    group = get_tensor_model_parallel_group().device_group
 
     # A small all_reduce for warmup.
     # this is needed because device communicators might be created lazily