From 84f465e791f4957921b1452fc239fa6794c96f22 Mon Sep 17 00:00:00 2001
From: Jedrzej Kosinski <kosinkadink1@gmail.com>
Date: Mon, 30 Mar 2026 07:07:54 -0700
Subject: [PATCH] Set CUDA device at start of multigpu threads to avoid
 multithreading bugs

Amp-Thread-ID: https://ampcode.com/threads/T-019d3ee9-19d5-767a-9d7a-e50cbbef815b
Co-authored-by: Amp <amp@ampcode.com>
---
 comfy/samplers.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/comfy/samplers.py b/comfy/samplers.py
index ab691ed5b..1ff50f51d 100755
--- a/comfy/samplers.py
+++ b/comfy/samplers.py
@@ -444,6 +444,7 @@ def _calc_cond_batch_multigpu(model: BaseModel, conds: list[list[dict]], x_in: t
 
     def _handle_batch(device: torch.device, batch_tuple: tuple[comfy.hooks.HookGroup, tuple], results: list[thread_result]):
         try:
+            torch.cuda.set_device(device)
             model_current: BaseModel = model_options["multigpu_clones"][device].model
             # run every hooked_to_run separately
             with torch.no_grad():