diff --git a/cmd/stress/cgr-spansstress/cgr-spansstress.go b/cmd/stress/cgr-spansstress/cgr-spansstress.go
index 199c0cc20..bc233e8fe 100644
--- a/cmd/stress/cgr-spansstress/cgr-spansstress.go
+++ b/cmd/stress/cgr-spansstress/cgr-spansstress.go
@@ -35,6 +35,7 @@ var (
 
 func main() {
 	flag.Parse()
+	runtime.GOMAXPROCS(runtime.NumCPU() - 1)
 
 	if *cpuprofile != "" {
 		f, err := os.Create(*cpuprofile)