Re: [LKP] [sched/fair] 070f5e860e: reaim.jobs_per_min -10.5% regression

Vincent Guittot
2020-06-16T06:54:42Z

Hi Xing,

Le mardi 16 juin 2020 à 11:17:16 (+0800), Xing Zhengjun a écrit :
>
>
> On 6/15/2020 4:10 PM, Vincent Guittot wrote:
> > Hi Xing,
> >
> > Le lundi 15 juin 2020 à 15:26:59 (+0800), Xing Zhengjun a écrit :
> > >
> > >
> > > On 6/12/2020 7:06 PM, Hillf Danton wrote:
> > > >
> > > > On Fri, 12 Jun 2020 14:36:49 +0800 Xing Zhengjun wrote:
> >

...

> >
>
> I apply the patch based on v5.7, the test result is as the following:

TBH, I didn't expect that the results would still be bad, so i wonder if the threshold are
the root problem.

Could you run tests with the patch below that removes condition with runnable_avg ?
I just want to make sure that those 2 conditions are the root cause.

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index da3e5b54715b..f5774d0af059 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8210,10 +8210,6 @@ group_has_capacity(unsigned int imbalance_pct, struct sg_lb_stats *sgs)
if (sgs->sum_nr_running < sgs->group_weight)
return true;

- if ((sgs->group_capacity * imbalance_pct) <
- (sgs->group_runnable * 100))
- return false;
-
if ((sgs->group_capacity * 100) >
(sgs->group_util * imbalance_pct))
return true;
@@ -8239,10 +8235,6 @@ group_is_overloaded(unsigned int imbalance_pct, struct sg_lb_stats *sgs)
(sgs->group_util * imbalance_pct))
return true;

- if ((sgs->group_capacity * imbalance_pct) <
- (sgs->group_runnable * 100))
- return true;
-
return false;
}

Thanks.
Vincent

>
> =========================================================================================
> tbox_group/testcase/rootfs/kconfig/compiler/runtime/nr_task/debug-setup/test/cpufreq_governor/ucode:
>
> lkp-ivb-d04/reaim/debian-x86_64-20191114.cgz/x86_64-rhel-7.6/gcc-7/300s/100%/test/five_sec/performance/0x21
>
> commit:
> 9f68395333ad7f5bfe2f83473fed363d4229f11c
> 070f5e860ee2bf588c99ef7b4c202451faa48236
> v5.7
> 3e1643da53f3fc7414cfa3ad2a16ab2a164b7f4d (the test patch)
>
> 9f68395333ad7f5b 070f5e860ee2bf588c99ef7b4c2 v5.7
> 3e1643da53f3fc7414cfa3ad2a1
> ---------------- --------------------------- ---------------------------
> ---------------------------
> %stddev %change %stddev %change %stddev %change
> %stddev
> \ | \ | \
> | \
> 0.69 -10.3% 0.62 -9.1% 0.62
> -7.1% 0.64 reaim.child_systime
> 0.62 -1.0% 0.61 +0.5% 0.62
> +1.3% 0.63 reaim.child_utime
> 66870 -10.0% 60187 -7.6% 61787
> -6.1% 62807 reaim.jobs_per_min
> 16717 -10.0% 15046 -7.6% 15446
> -6.1% 15701 reaim.jobs_per_min_child
> 97.84 -1.1% 96.75 -0.4% 97.43
> -0.5% 97.34 reaim.jti
> 72000 -10.8% 64216 -8.3% 66000
> -5.7% 67885 reaim.max_jobs_per_min
> 0.36 +10.6% 0.40 +7.8% 0.39
> +6.9% 0.38 reaim.parent_time
> 1.58 ± 2% +71.0% 2.70 ± 2% +26.9% 2.01 ± 2%
> +32.5% 2.09 ± 6% reaim.std_dev_percent
> 0.00 ± 5% +110.4% 0.01 ± 3% +48.8% 0.01 ± 7%
> +61.7% 0.01 ± 8% reaim.std_dev_time
> 50800 -2.4% 49600 -1.6% 50000
> -1.3% 50133 reaim.workload
>
>
> > >
> > > =========================================================================================
> > > tbox_group/testcase/rootfs/kconfig/compiler/runtime/nr_task/debug-setup/test/cpufreq_governor/ucode:
> > >
> > > lkp-ivb-d04/reaim/debian-x86_64-20191114.cgz/x86_64-rhel-7.6/gcc-7/300s/100%/test/five_sec/performance/0x21
> > >
> > > commit:
> > > 9f68395333ad7f5bfe2f83473fed363d4229f11c
> > > 070f5e860ee2bf588c99ef7b4c202451faa48236
> > > v5.7
> > > 6b33257768b8dd3982054885ea310871be2cfe0b (Hillf's patch)
> > >
> > > 9f68395333ad7f5b 070f5e860ee2bf588c99ef7b4c2 v5.7
> > > 6b33257768b8dd3982054885ea3
> > > ---------------- --------------------------- ---------------------------
> > > ---------------------------
> > > %stddev %change %stddev %change %stddev %change
> > > %stddev
> > > \ | \ | \
> > > | \
> > > 0.69 -10.3% 0.62 -9.1% 0.62
> > > -10.1% 0.62 reaim.child_systime
> > > 0.62 -1.0% 0.61 +0.5% 0.62
> > > +0.3% 0.62 reaim.child_utime
> > > 66870 -10.0% 60187 -7.6% 61787
> > > -8.3% 61305 reaim.jobs_per_min
> > > 16717 -10.0% 15046 -7.6% 15446
> > > -8.3% 15326 reaim.jobs_per_min_child
> > > 97.84 -1.1% 96.75 -0.4% 97.43
> > > -0.5% 97.37 reaim.jti
> > > 72000 -10.8% 64216 -8.3% 66000
> > > -8.3% 66000 reaim.max_jobs_per_min
> > > 0.36 +10.6% 0.40 +7.8% 0.39
> > > +9.4% 0.39 reaim.parent_time
> > > 1.58 ± 2% +71.0% 2.70 ± 2% +26.9% 2.01 ± 2%
> > > +33.2% 2.11 reaim.std_dev_percent
> > > 0.00 ± 5% +110.4% 0.01 ± 3% +48.8% 0.01 ± 7%
> > > +65.3% 0.01 ± 3% reaim.std_dev_time
> > > 50800 -2.4% 49600 -1.6% 50000
> > > -1.8% 49866 reaim.workload
> > >
> > >
> > >
> > > --
> > > Zhengjun Xing
>
> --
> Zhengjun Xing