[libc++][ci] Pin apple-system to arm64 to relieve pressure on x86_64 hosts

diff --git a/libcxx/utils/ci/buildkite-pipeline.yml b/libcxx/utils/ci/buildkite-pipeline.yml
index bd66db0..31d2825 100644 (file)
--- a/libcxx/utils/ci/buildkite-pipeline.yml
+++ b/libcxx/utils/ci/buildkite-pipeline.yml
@@ -603,6 +603,7 @@ steps:
       agents:
         queue: "libcxx-builders"
         os: "macos"
+        arch: "arm64" # This can technically run on any architecture, but we have more resources on arm64 so we pin this job to arm64
       retry:
         automatic:
           - exit_status: -1  # Agent was lost