Set GOMAXPROCS appropriately
diff --git a/main.go b/main.go
index d8a9592..5eabbb2 100644
--- a/main.go
+++ b/main.go
@@ -189,6 +189,7 @@
 }
 
 func main() {
+	runtime.GOMAXPROCS(runtime.NumCPU())
 	parseFlags()
 	if cpuprofile != "" {
 		f, err := os.Create(cpuprofile)