diff --git a/build/ci.go b/build/ci.go
index 5ada194772..5b2e1d98f7 100644
--- a/build/ci.go
+++ b/build/ci.go
@@ -281,15 +281,16 @@ func buildFlags(env build.Environment, staticLinking bool, buildTags []string) (
 
 func doTest(cmdline []string) {
 	var (
-		dlgo       = flag.Bool("dlgo", false, "Download Go and build with it")
-		arch       = flag.String("arch", "", "Run tests for given architecture")
-		cc         = flag.String("cc", "", "Sets C compiler binary")
-		coverage   = flag.Bool("coverage", false, "Whether to record code coverage")
-		verbose    = flag.Bool("v", false, "Whether to log verbosely")
-		race       = flag.Bool("race", false, "Execute the race detector")
-		short      = flag.Bool("short", false, "Pass the 'short'-flag to go test")
-		cachedir   = flag.String("cachedir", "./build/cache", "directory for caching downloads")
+		dlgo          = flag.Bool("dlgo", false, "Download Go and build with it")
+		arch          = flag.String("arch", "", "Run tests for given architecture")
+		cc            = flag.String("cc", "", "Sets C compiler binary")
+		coverage      = flag.Bool("coverage", false, "Whether to record code coverage")
+		verbose       = flag.Bool("v", false, "Whether to log verbosely")
+		race          = flag.Bool("race", false, "Execute the race detector")
+		short         = flag.Bool("short", false, "Pass the 'short'-flag to go test")
+		cachedir      = flag.String("cachedir", "./build/cache", "directory for caching downloads")
 		skipspectests = flag.Bool("skip-spectests", false, "Skip downloading execution-spec-tests fixtures")
+		threads       = flag.Int("threads", 1, "Number of CPU threads to use for testing")
 	)
 	flag.CommandLine.Parse(cmdline)
 
@@ -320,7 +321,7 @@ func doTest(cmdline []string) {
 
 	// Test a single package at a time. CI builders are slow
 	// and some tests run into timeouts under load.
-	gotest.Args = append(gotest.Args, "-p", "1")
+	gotest.Args = append(gotest.Args, "-p", *threads)
 	if *coverage {
 		gotest.Args = append(gotest.Args, "-covermode=atomic", "-cover")
 	}