Benchmarks: Revise Test - Revise benchmark test util to support pytorch multi-GPU test (#54)

* Superbenchmark: Revise tests - revise benchmark test util to support multi gpu test

* modify test_sharding_matmul.py to match the tests util

tests/__init__.py

+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT License.
+
+"""Module for tests."""

tests/benchmarks/micro_benchmarks/test_sharding_matmul.py

@@ -22,7 +22,7 @@ def test_pytorch_sharding_matmul():
 
     assert (BenchmarkRegistry.is_benchmark_context_valid(context))
 
-    utils.setup_simulated_ddp_distributed_env()
+    utils.setup_simulated_ddp_distributed_env(1, 0, utils.get_free_port())
     benchmark = BenchmarkRegistry.launch_benchmark(context)
 
     # Check basic information.

tests/benchmarks/utils.py

@@ -4,15 +4,12 @@
 """Utilities for benchmark tests."""
 
 import os
+import socket
+from contextlib import closing
+import multiprocessing as multiprocessing
+from multiprocessing import Process
 
-
-def setup_simulated_ddp_distributed_env():
-    """Function to setup the simulated DDP distributed envionment variables."""
-    os.environ['WORLD_SIZE'] = '1'
-    os.environ['RANK'] = '0'
-    os.environ['LOCAL_RANK'] = '0'
-    os.environ['MASTER_ADDR'] = 'localhost'
-    os.environ['MASTER_PORT'] = '12345'
+from superbench.benchmarks import BenchmarkRegistry
 
 
 def clean_simulated_ddp_distributed_env():
@@ -22,3 +19,57 @@ def clean_simulated_ddp_distributed_env():
     os.environ.pop('LOCAL_RANK')
     os.environ.pop('MASTER_ADDR')
     os.environ.pop('MASTER_PORT')
+
+
+def get_free_port():
+    """Get a free port in current system.
+
+    Return:
+        port (int): a free port in current system.
+    """
+    with closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as s:
+        s.bind(('', 0))
+        s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        return s.getsockname()[1]
+
+
+def setup_simulated_ddp_distributed_env(world_size, local_rank, port):
+    """Function to setup the simulated DDP distributed envionment variables."""
+    os.environ['WORLD_SIZE'] = str(world_size)
+    os.environ['RANK'] = str(local_rank)
+    os.environ['LOCAL_RANK'] = str(local_rank)
+    os.environ['MASTER_ADDR'] = 'localhost'
+    os.environ['MASTER_PORT'] = str(port)
+
+
+def benchmark_in_one_process(context, world_size, local_rank, port, queue):
+    """Function to setup env for DDP initialization and run the benchmark in each single process."""
+    setup_simulated_ddp_distributed_env(world_size, local_rank, port)
+    benchmark = BenchmarkRegistry.launch_benchmark(context)
+    # parser object must be removed becaues it can not be serialized.
+    benchmark._parser = None
+    queue.put(benchmark)
+    clean_simulated_ddp_distributed_env()
+
+
+def simulated_ddp_distributed_benchmark(context, world_size):
+    """Function to run the benchmark on #world_size number of processes.
+
+    Return:
+        results (list): list of benchmark results from #world_size number of processes.
+    """
+    port = get_free_port()
+    process_list = []
+    multiprocessing.set_start_method('spawn')
+
+    queue = multiprocessing.Queue()
+
+    for rank in range(world_size):
+        process = Process(target=benchmark_in_one_process, args=(context, world_size, rank, port, queue))
+        process.start()
+        process_list.append(process)
+
+    for process in process_list:
+        process.join()
+    results = [queue.get(1) for p in process_list]
+    return results