Messages in this thread | | | Subject | Re: [LKP] [sched/fair] 070f5e860e: reaim.jobs_per_min -10.5% regression | From | Xing Zhengjun <> | Date | Tue, 16 Jun 2020 11:24:05 +0800 |
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On 6/15/2020 11:10 PM, Hillf Danton wrote: > > On Mon, 15 Jun 2020 10:10:41 +0200 Vincent Guittot wrote: >> Le lundi 15 juin 2020 15:26:59 (+0800), Xing Zhengjun a crit : >>> >>> 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 regression still existed. >> >> Thanks for the test. > > Thanks. > >> I don't know if it's relevant or not but the results seem a bit >> better with the patch and I'd like to check that it's only a matter of threshold to >> fix the problem. >> >> Could you try the patch below which is quite aggressive but will help to confirm this ? >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index 28be1c984a42..3c51d557547b 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -8322,10 +8322,13 @@ static inline int sg_imbalanced(struct sched_group *group) >> static inline bool >> group_has_capacity(unsigned int imbalance_pct, struct sg_lb_stats *sgs) >> { >> + unsigned long imb; >> + >> if (sgs->sum_nr_running < sgs->group_weight) >> return true; >> >> - if ((sgs->group_capacity * imbalance_pct) < >> + imb = sgs->sum_nr_running * 100; >> + if ((sgs->group_capacity * imb) < >> (sgs->group_runnable * 100)) >> return false; >> >> @@ -8347,6 +8350,8 @@ group_has_capacity(unsigned int imbalance_pct, struct sg_lb_stats *sgs) >> static inline bool >> group_is_overloaded(unsigned int imbalance_pct, struct sg_lb_stats *sgs) >> { >> + unsigned long imb; >> + >> if (sgs->sum_nr_running <= sgs->group_weight) >> return false; >> >> @@ -8354,7 +8359,8 @@ 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) < >> + imb = sgs->sum_nr_running * 100; >> + if ((sgs->group_capacity * imb) < >> (sgs->group_runnable * 100)) >> return true; >> >> >>> >>> ========================================================================================= >>> 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 >>> > > Following the introduction of runnable_avg there came a gap between it > and util, and it can be supposedly filled up by determining the pivot > point using the imb percent. The upside is that no heuristic is added. > > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -8215,15 +8215,8 @@ group_has_capacity(unsigned int imbalanc > 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; > - > - return false; > + return sgs->group_capacity * imbalance_pct > > + (sgs->group_util + sgs->group_runnable) *50; > } > > /* > @@ -8240,15 +8233,8 @@ group_is_overloaded(unsigned int imbalan > if (sgs->sum_nr_running <= sgs->group_weight) > return false; > > - if ((sgs->group_capacity * 100) < > - (sgs->group_util * imbalance_pct)) > - return true; > - > - if ((sgs->group_capacity * imbalance_pct) < > - (sgs->group_runnable * 100)) > - return true; > - > - return false; > + return sgs->group_capacity * imbalance_pct < > + (sgs->group_util + sgs->group_runnable) *50; > } > > /* >
I apply the patch based on v5.7, the test result is as the following: ========================================================================================= 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 1d5ee1e6dab1f8903cd7219fbcc5ac2f728ac80c (the test patch)
9f68395333ad7f5b 070f5e860ee2bf588c99ef7b4c2 v5.7 1d5ee1e6dab1f8903cd7219fbcc ---------------- --------------------------- --------------------------- --------------------------- %stddev %change %stddev %change %stddev %change %stddev \ | \ | \ | \ 0.69 -10.3% 0.62 -9.1% 0.62 -6.8% 0.64 reaim.child_systime 0.62 -1.0% 0.61 +0.5% 0.62 +0.6% 0.62 reaim.child_utime 66870 -10.0% 60187 -7.6% 61787 -5.7% 63058 reaim.jobs_per_min 16717 -10.0% 15046 -7.6% 15446 -5.7% 15764 reaim.jobs_per_min_child 97.84 -1.1% 96.75 -0.4% 97.43 -0.5% 97.31 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 +6.0% 0.38 reaim.parent_time 1.58 ± 2% +71.0% 2.70 ± 2% +26.9% 2.01 ± 2% +33.1% 2.10 ± 3% reaim.std_dev_percent 0.00 ± 5% +110.4% 0.01 ± 3% +48.8% 0.01 ± 7% +58.1% 0.01 ± 6% reaim.std_dev_time 50800 -2.4% 49600 -1.6% 50000 -0.8% 50400 reaim.workload
-- Zhengjun Xing
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