--- a/src/jdk.internal.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotVMConfigStore.java	Tue May 07 10:21:04 2019 +0800
+++ b/src/jdk.internal.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotVMConfigStore.java	Mon May 06 20:05:19 2019 -0700
@@ -193,8 +193,7 @@
     private static void printConfigLine(CompilerToVM vm, String format, Object... args) {
         String line = String.format(format, args);
         byte[] lineBytes = line.getBytes();
-        vm.writeDebugOutput(lineBytes, 0, lineBytes.length);
-        vm.flushDebugOutput();
+        vm.writeDebugOutput(lineBytes, 0, lineBytes.length, true, true);
     }
 
 }