On 6/24/2013 6:01 AM, Paolo Bonzini wrote:
One nit and one question:
Il 23/06/2013 22:11, Chegu Vinod ha scritto:
@@ -404,6 +413,23 @@ static void migration_bitmap_sync(void)
/* more than 1 second = 1000 millisecons */
if (end_time > start_time + 1000) {
+ if (migrate_auto_converge()) {
+ /* The following detection logic can be refined later. For now:
+ Check to see if the dirtied bytes is 50% more than the approx.
+ amount of bytes that just got transferred since the last time we
+ were in this routine. If that happens >N times (for now N==4)
+ we turn on the throttle down logic */
+ bytes_xfer_now = ram_bytes_transferred();
+ if (s->dirty_pages_rate &&
+ (num_dirty_pages_period * TARGET_PAGE_SIZE >
+ (bytes_xfer_now - bytes_xfer_prev)/2) &&
+ (dirty_rate_high_cnt++ > 4)) {
+ trace_migration_throttle();
+ mig_throttle_on = true;
+ dirty_rate_high_cnt = 0;
+ }
+ bytes_xfer_prev = bytes_xfer_now;
+ }
Missing:
else {
mig_throttle_on = false;
}
Ok.
+/* Stub function that's gets run on the vcpu when its brought out of the
+ VM to run inside qemu via async_run_on_cpu()*/
+static void mig_sleep_cpu(void *opq)
+{
+ qemu_mutex_unlock_iothread();
+ g_usleep(30*1000);
+ qemu_mutex_lock_iothread();
+}
+
+ /* If it has been more than 40 ms since the last time the guest
+ * was throttled then do it again.
+ */
+ if (40 < (t1-t0)/1000000) {
You're stealing 75% of the CPU time, isn't that a lot?
Depends on the dirty rate vs. transfer rate... I had tried 50% too and
it took much longer for the migration to converge.
Vinod
+ mig_throttle_guest_down();
+ t0 = t1;
+ }
+}
Paolo
.
