diff --git a/mysql-test/mysql-test-run.pl b/mysql-test/mysql-test-run.pl
index 25cf8f46832d..d209e520b39f 100755
--- a/mysql-test/mysql-test-run.pl
+++ b/mysql-test/mysql-test-run.pl
@@ -1784,9 +1784,12 @@ ($)
   if ( lc($opt_build_thread) eq 'auto' ) {
     my $found_free = 0;
     $build_thread = 300;	# Start attempts from here
+    my $build_thread_upper = $build_thread + ($opt_parallel > 49
+                                              ? $opt_parallel
+                                              : 49);
     while (! $found_free)
     {
-      $build_thread= mtr_get_unique_id($build_thread, 349);
+      $build_thread= mtr_get_unique_id($build_thread, $build_thread_upper);
       if ( !defined $build_thread ) {
         mtr_error("Could not get a unique build thread id");
       }