From 47eeb2b28c8c6b7aa7551381cf80ef0c28541775 Mon Sep 17 00:00:00 2001
From: Jan Tattermusch <jtattermusch@google.com>
Date: Wed, 7 Oct 2015 14:09:18 -0700
Subject: [PATCH] reduce parallelism for windows build

---
 tools/run_tests/run_tests.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/run_tests/run_tests.py b/tools/run_tests/run_tests.py
index 4e71e3e4b64..a05fbe806a8 100755
--- a/tools/run_tests/run_tests.py
+++ b/tools/run_tests/run_tests.py
@@ -624,7 +624,9 @@ if platform.system() == 'Windows':
   def make_jobspec(cfg, targets, makefile='Makefile'):
     extra_args = []
     # better do parallel compilation
-    extra_args.extend(["/m"])
+    # empirically /m:2 gives the best performance/price and should prevent
+    # overloading the windows workers.
+    extra_args.extend(["/m:2"])
     # disable PDB generation: it's broken, and we don't need it during CI
     extra_args.extend(["/p:Jenkins=true"])
     return [