diff --git a/common.ant.xml b/common.ant.xml
index 1bbd0e1..2e2c78a 100755
--- a/common.ant.xml
+++ b/common.ant.xml
@@ -37,6 +37,7 @@
   <property name="gwt.build.jni" location="${gwt.build}/jni" />
   <property name="gwt.build.staging" location="${gwt.build}/staging" />
   <property name="gwt.build.dist" location="${gwt.build}/dist" />
+  <property name="gwt.threadsPerProcessor" value="1" />
   <property name="project.build" location="${gwt.build.out}/${project.tail}" />
   <property name="project.lib" location="${gwt.build.lib}/gwt-${ant.project.name}.jar" />
   <property name="project.jni" location="${gwt.build}/${project.tail}" />
diff --git a/user/build.xml b/user/build.xml
index df207ce..196959a 100755
--- a/user/build.xml
+++ b/user/build.xml
@@ -157,7 +157,7 @@
       is executing
     -->
     <limit failonerror="true" hours="2">
-    <parallel threadsPerProcessor="1">
+    <parallel threadsPerProcessor="${gwt.threadsPerProcessor}">
       <!-- selenium-test is a no-op unless gwt.selenium.hosts is defined -->
       <antcall target="selenium-test"/>
       <!-- remoteweb-test is a no-op unless gwt.remote.browsers is defined -->