TP/quantization/weight loading refactor part 1 - Simplify parallel linear logic (#1181)

tests/distributed/test_comm_ops.py

@@ -0,0 +1,82 @@
+"""Test the communication operators.
+
+Run `pytest tests/distributed/test_comm_ops.py --forked`.
+"""
+from multiprocessing import Process
+
+import pytest
+import torch
+
+from vllm.config import ParallelConfig
+from vllm.engine.ray_utils import get_open_port
+from vllm.model_executor.parallel_utils.communication_op import (
+    tensor_model_parallel_all_reduce,
+    tensor_model_parallel_all_gather,
+)
+from vllm.worker.worker import _init_distributed_environment
+
+
+def init_test_distributed_environment(pipeline_parallel_size: int,
+                                      tensor_parallel_size: int, rank: int,
+                                      distributed_init_port: str):
+    parallel_config = ParallelConfig(pipeline_parallel_size,
+                                     tensor_parallel_size,
+                                     worker_use_ray=True)
+    distributed_init_method = f"tcp://localhost:{distributed_init_port}"
+    torch.cuda.set_device(rank)
+    _init_distributed_environment(parallel_config, rank,
+                                  distributed_init_method)
+
+
+def all_reduce_test_worker(tensor_parallel_size: int, rank: int,
+                           distributed_init_port: str):
+    init_test_distributed_environment(1, tensor_parallel_size, rank,
+                                      distributed_init_port)
+    num_elements = 8
+    all_tensors = [
+        torch.arange(num_elements, dtype=torch.float32, device="cuda") *
+        (r + 1) for r in range(tensor_parallel_size)
+    ]
+    expected = torch.sum(torch.stack(all_tensors, dim=0), dim=0)
+    t = all_tensors[rank]
+    t = tensor_model_parallel_all_reduce(t)
+    assert torch.allclose(t, expected)
+
+
+def all_gather_test_worker(tensor_parallel_size: int, rank: int,
+                           distributed_init_port: str):
+    init_test_distributed_environment(1, tensor_parallel_size, rank,
+                                      distributed_init_port)
+    num_dimensions = 3
+    tensor_size = list(range(2, num_dimensions + 2))
+    total_size = 1
+    for s in tensor_size:
+        total_size *= s
+    for all_gather_dimension in range(num_dimensions):
+        all_tensors = [
+            torch.arange(total_size, dtype=torch.float32,
+                         device="cuda").reshape(tensor_size) * (r + 1)
+            for r in range(tensor_parallel_size)
+        ]
+        expected = torch.cat(all_tensors, dim=all_gather_dimension)
+        t = all_tensors[rank]
+        t = tensor_model_parallel_all_gather(t, all_gather_dimension)
+        assert torch.allclose(t, expected)
+
+
+@pytest.mark.skipif(torch.cuda.device_count() < 2,
+                    reason="Need at least 2 GPUs to run the test.")
+@pytest.mark.parametrize("tensor_parallel_size", [2])
+@pytest.mark.parametrize("test_target",
+                         [all_reduce_test_worker, all_gather_test_worker])
+def test_multi_process_tensor_parallel(tensor_parallel_size, test_target):
+    distributed_init_port = get_open_port()
+    processes = []
+    for rank in range(tensor_parallel_size):
+        p = Process(target=test_target,
+                    args=(tensor_parallel_size, rank, distributed_init_port))
+        p.start()
+        processes.append(p)
+    for p in processes:
+        p.join()
+    assert all(p.exitcode == 0 for p in processes)