diff -r e122485df37b xen/common/sched_credit.c
--- a/xen/common/sched_credit.c	Thu Dec 01 16:50:05 2011 +0000
+++ b/xen/common/sched_credit.c	Thu Dec 01 16:55:27 2011 +0000
@@ -1307,6 +1307,18 @@ csched_schedule(
     CSCHED_STAT_CRANK(schedule);
     CSCHED_VCPU_CHECK(current);
 
+    sd = &this_cpu(schedule_data);
+    sd->s_csnum++;
+    if ((now - sd->s_src_b) >= MILLISECS(SCHED_SRC_INTERVAL))
+    {
+        if (sd->s_csnum >= SCHED_SRC_THRESHOLD)
+            sched_ratelimit_us = 1000;
+        else
+            sched_ratelimit_us = 0;
+	sd->s_src_b = now;
+	sd->s_csnum = 0;
+    }
+        
     runtime = now - current->runstate.state_entry_time;
     if ( runtime < 0 ) /* Does this ever happen? */
         runtime = 0;
diff -r e122485df37b xen/common/schedule.c
--- a/xen/common/schedule.c	Thu Dec 01 16:50:05 2011 +0000
+++ b/xen/common/schedule.c	Thu Dec 01 16:55:27 2011 +0000
@@ -1261,6 +1261,8 @@ static int cpu_schedule_up(unsigned int 
     sd->curr = idle_vcpu[cpu];
     init_timer(&sd->s_timer, s_timer_fn, NULL, cpu);
     atomic_set(&sd->urgent_count, 0);
+    sd->s_csnum=0;
+    sd->s_src_b=0;
 
     /* Boot CPU is dealt with later in schedule_init(). */
     if ( cpu == 0 )
diff -r e122485df37b xen/include/xen/sched-if.h
--- a/xen/include/xen/sched-if.h	Thu Dec 01 16:50:05 2011 +0000
+++ b/xen/include/xen/sched-if.h	Thu Dec 01 16:55:27 2011 +0000
@@ -15,6 +15,10 @@ extern struct cpupool *cpupool0;
 
 /* cpus currently in no cpupool */
 extern cpumask_t cpupool_free_cpus;
+/* The period that SRC updated scheduler frequency */
+#define SCHED_SRC_INTERVAL       10
+/* Threshold to trigger SRC,  */
+#define SCHED_SRC_THRESHOLD     50
 
 /*
  * In order to allow a scheduler to remap the lock->cpu mapping,
@@ -32,6 +36,9 @@ struct schedule_data {
     struct vcpu        *curr;           /* current task                    */
     void               *sched_priv;
     struct timer        s_timer;        /* scheduling timer                */
+    int                 s_csnum;        /* scheduling number based on last period */
+    s_time_t            s_src_b;        /* SRC conting start point */
+    bool_t              s_src_c;        /*indicate whether src should be triggered */
     atomic_t            urgent_count;   /* how many urgent vcpus           */
 };