[test] refactor tests with spawn (#3452)

* [test] added spawn decorator

* polish code

* polish code

* polish code

* polish code

* polish code

* polish code

colossalai/utils/__init__.py

@@ -7,7 +7,6 @@ from .common import (
     count_zeros_fp32,
     disposable,
     ensure_path_exists,
-    free_port,
     is_ddp_ignored,
     is_dp_rank_0,
     is_model_parallel_parameter,
@@ -37,7 +36,6 @@ from .timer import MultiTimer, Timer
 
 __all__ = [
     'checkpoint',
-    'free_port',
     'print_rank_0',
     'sync_model_param',
     'is_ddp_ignored',

colossalai/utils/common.py

@@ -50,23 +50,6 @@ def ensure_path_exists(filename: str):
         Path(dirpath).mkdir(parents=True, exist_ok=True)
 
 
-def free_port() -> int:
-    """Get a free port on localhost.
-
-    Returns:
-        int: A free port on localhost.
-    """
-    while True:
-        port = random.randint(20000, 65000)
-        try:
-            with socket.socket() as sock:
-                sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-                sock.bind(("localhost", port))
-                return port
-        except OSError:
-            continue
-
-
 def sync_model_param(model, parallel_mode):
     r"""Make sure data parameters are consistent during Data Parallel Mode.