Messages in this thread Patch in this message | | | Subject | [performance bug] volanomark regression on 37-rc1 | From | "Alex,Shi" <> | Date | Tue, 16 Nov 2010 17:34:02 +0800 |
| |
When do performance testing on 37-rc1 kernel on Core2 machines, we find the volanomark loopback performance drop about 30%, that due to commit:fab476228ba37907ad7
Volanomark link: http://www.volano.com/benchmarks.html Our volanomark testing parameters as following: "-count 25000 -rooms 10 " JVM is jrockit-R27.3.1-jre1.5.0_11 java_options is "-Xmx1500m -Xms1500m -Xns750m -XXaggressive -Xlargepages -XXlazyUnlocking -Xgc:genpar -XXtlasize:min=16k,preferred=64k" and we set /proc/sys/kernel/sched_compat_yield as "1".
We find if with the following patch, the regression can be recovered.
Signed-off-by:Alex Shi <alex.shi@intel.com>
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index f4f6a83..5dca678 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1766,7 +1766,6 @@ static void pull_task(struct rq *src_rq, struct task_struct *p, check_preempt_curr(this_rq, p, 0); /* re-arm NEWIDLE balancing when moving tasks */ - src_rq->avg_idle = this_rq->avg_idle = 2*sysctl_sched_migration_cost; this_rq->idle_stamp = 0; } It seems some of load_balance() is not necessary that caused by avg_idle setting. But do not know more details of the volano running. Anyone like to give a comments for this issue?
Ncrao, I have no idea of your benchmarks, but just guess removing the avg_idle setting won't bring much wakeup delay for tasks. Could you like to show some data of this?
The vmstat output for .36 and .37-rc1 kernel as below: 2.6.36 procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ r b swpd free buff cache si so bi bo in cs us sy id wa st 394 0 0 4680728 3168 118972 0 0 0 3 5314 1348711 38 62 0 0 0 396 0 0 4680500 3184 118976 0 0 0 8 5345 1303237 38 62 0 0 0 413 0 0 4680252 3200 118976 0 0 0 3 5082 1326851 38 61 0 0 0 2.6.37-rc1 procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ r b swpd free buff cache si so bi bo in cs us sy id wa st 329 0 0 4653748 4600 134032 0 0 0 7 11649 918370 35 64 0 0 0 210 0 0 4653492 4608 134032 0 0 0 6 11957 898011 36 64 0 0 0 373 0 0 4653496 4624 134032 0 0 0 4 11736 912468 36 64 0 0 0 Regards Alex
| |