From f5df720c2768805dcc78019f55e710c558b96b06 Mon Sep 17 00:00:00 2001
From: fae713 <favourmichael47@gmail.com>
Date: Wed, 6 Aug 2025 17:48:55 +0100
Subject: [PATCH] fix: set multiprocessing start method to 'spawn' to prevent
 PyTorch shared memory timeout on CPU

---
 rgym_exp/runner/swarm_launcher.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/rgym_exp/runner/swarm_launcher.py b/rgym_exp/runner/swarm_launcher.py
index 479a1f70..dc9432c6 100644
--- a/rgym_exp/runner/swarm_launcher.py
+++ b/rgym_exp/runner/swarm_launcher.py
@@ -1,5 +1,10 @@
 import os
 
+# Set multiprocessing start method to 'spawn' safely
+import torch.multiprocessing as mp
+if mp.get_start_method(allow_none=True) != 'spawn':
+    mp.set_start_method('spawn', force=True)
+
 import hydra
 from genrl.communication.communication import Communication
 from genrl.communication.hivemind.hivemind_backend import (