From 113bc5a9e2e6c35327275fd33b8d45a81e3a22d6 Mon Sep 17 00:00:00 2001
From: Tim Besard <tim.besard@gmail.com>
Date: Fri, 25 Sep 2026 14:10:21 +0200
Subject: [PATCH] CI: run CUDA.jl's tests with 3 CPU threads

The CUDA agents budget 2 threads per job, which limits CUDA.jl's test suite to
2 workers even though it is compile-bound and the CI hosts have CPU to spare.
CUDA.jl's runtests.jl still caps the worker count by the available GPU memory.
---
 .buildkite/downstream.yml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/.buildkite/downstream.yml b/.buildkite/downstream.yml
index f0a928c2..da521c0e 100644
--- a/.buildkite/downstream.yml
+++ b/.buildkite/downstream.yml
@@ -23,6 +23,11 @@ steps:
                 Pkg.test("CUDA"; coverage=true)'
     agents:
       queue: "cuda"
+    env:
+      # The agents budget 2 threads per job, but CUDA.jl's test suite is compile-bound
+      # and the CI hosts have CPU to spare. This raises the number of test workers,
+      # which CUDA.jl's runtests.jl still caps by the available GPU memory.
+      JULIA_CPU_THREADS: "3"
     if_changed:
       include: &sources
         - "src/**"