diff --git a/perl-xCAT-2.0/xCAT/PPC.pm b/perl-xCAT-2.0/xCAT/PPC.pm
index 604682b2c..b9424755e 100644
--- a/perl-xCAT-2.0/xCAT/PPC.pm
+++ b/perl-xCAT-2.0/xCAT/PPC.pm
@@ -110,7 +110,7 @@ sub process_command {
 
     foreach ( @$nodes ) {
         while ( $children > $maxp ) {
-            sleep(0.1);
+            Time::HiRes::sleep(0.1);
         }
         my $pipe = fork_cmd( @$_[0], @$_[1], $request );
         if ( $pipe ) {