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

[Vincent Guittot <vincent.guittot@linaro.org>]

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