From 498e756456a4548863537a276a4291d97c4b3414 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=81=82=E9=9D=96=E5=85=A5?= <niejingru@bytedance.com>
Date: Wed, 25 Oct 2023 03:46:35 +0000
Subject: [PATCH] check port availability only in main launcher for
 deepspeed/torchrun

---
 src/accelerate/utils/launch.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/accelerate/utils/launch.py b/src/accelerate/utils/launch.py
index cd4a9eb2188..9abed25defa 100644
--- a/src/accelerate/utils/launch.py
+++ b/src/accelerate/utils/launch.py
@@ -128,7 +128,8 @@ def prepare_multi_gpu_env(args: argparse.Namespace) -> Dict[str, str]:
     if main_process_port is None:
         main_process_port = 29500
 
-    if is_port_in_use(main_process_port):
+    need_port_check = num_machines <= 1 or int(args.machine_rank) == 0
+    if need_port_check and is_port_in_use(main_process_port):
         raise ConnectionError(
             f"Tried to launch distributed communication on port `{main_process_port}`, but another process is utilizing it. "
             "Please specify a different port (such as using the `----main_process_port` flag or specifying a different `main_process_port` in your config file)"