From: Tim Chen <tim.c.chen@linux.intel.com>
To: Yicong Yang <yangyicong@huawei.com>,
"Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com>,
Barry Song <21cnbao@gmail.com>,
"Gautham R. Shenoy" <gautham.shenoy@amd.com>
Cc: yangyicong@hisilicon.com,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
LKML <linux-kernel@vger.kernel.org>,
LAK <linux-arm-kernel@lists.infradead.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
"Zengtao (B)" <prime.zeng@hisilicon.com>,
Jonathan Cameron <jonathan.cameron@huawei.com>,
"ego@linux.vnet.ibm.com" <ego@linux.vnet.ibm.com>,
Linuxarm <linuxarm@huawei.com>,
Guodong Xu <guodong.xu@linaro.org>, Chen Yu <yu.c.chen@intel.com>
Subject: Re: [PATCH v2 2/2] sched/fair: Scan cluster before scanning LLC in wake-up path
Date: Thu, 17 Feb 2022 10:00:23 -0800 [thread overview]
Message-ID: <2627025ab96a315af0e76e5983c803578623c826.camel@linux.intel.com> (raw)
In-Reply-To: <eec56eba-59fd-5b12-d8f1-74a803ba7044@huawei.com>
On Wed, 2022-02-16 at 18:00 +0800, Yicong Yang wrote:
> On 2022/2/16 17:19, Song Bao Hua (Barry Song) wrote:
> >
> > tbench running on numa 0&1:
> > 5.17-rc1 rc1 + chenyu rc1+chenyu+cls rc1+chenyu+cls-pingpong rc1+cls
> > Hmean 1 320.01 ( 0.00%) 318.03 * -0.62%* 357.15 * 11.61%* 375.43 * 17.32%* 378.44 * 18.26%*
> > Hmean 2 643.85 ( 0.00%) 637.74 * -0.95%* 714.36 * 10.95%* 745.82 * 15.84%* 752.52 * 16.88%*
> > Hmean 4 1287.36 ( 0.00%) 1285.20 * -0.17%* 1431.35 * 11.18%* 1481.71 * 15.10%* 1505.62 * 16.95%*
> > Hmean 8 2564.60 ( 0.00%) 2551.02 * -0.53%* 2812.74 * 9.68%* 2921.51 * 13.92%* 2955.29 * 15.23%*
> > Hmean 16 5195.69 ( 0.00%) 5163.39 * -0.62%* 5583.28 * 7.46%* 5726.08 * 10.21%* 5814.74 * 11.91%*
> > Hmean 32 9769.16 ( 0.00%) 9815.63 * 0.48%* 10518.35 * 7.67%* 10852.89 * 11.09%* 10872.63 * 11.30%*
> > Hmean 64 15952.50 ( 0.00%) 15780.41 * -1.08%* 10608.36 * -33.50%* 17503.42 * 9.72%* 17281.98 * 8.33%*
> > Hmean 128 13113.77 ( 0.00%) 12000.12 * -8.49%* 13095.50 * -0.14%* 13991.90 * 6.70%* 13895.20 * 5.96%*
> > Hmean 256 10997.59 ( 0.00%) 12229.20 * 11.20%* 11902.60 * 8.23%* 12214.29 * 11.06%* 11244.69 * 2.25%*
> > Hmean 512 14623.60 ( 0.00%) 15863.25 * 8.48%* 14103.38 * -3.56%* 16422.56 * 12.30%* 15526.25 * 6.17%*
> >
>
> Yes I think it'll also benefit for the cluster's conditon.
>
> But 128 threads seems like a weired point that Chen's patch on 5.17-rc1 (without this series) causes degradation,
> which in Chen's tbench test it doesn't cause that much when the 2 * cpu number == threads[*]:
>
From the data, it seems like Chen Yu's patch benefits the overloaded condition (as expected) while
the cluster scheduling has benefit most at the low end (also expected). It is nice that
by combining these two approaches we can get the most benefit.
Chen Yu's patch has a hard transition to stop search for idle CPU at about 85% utilization.
So we may be hitting that knee and we may benefit from not stopping search completely
but reducing number of CPUs searched, as Peter pointed out.
Tim
> case load baseline(std%) compare%( std%)
> loopback thread-224 1.00 ( 0.17) +2.30 ( 0.10)
>
> [*] https://lore.kernel.org/lkml/20220207034013.599214-1-yu.c.chen@intel.com/
>
> > tbench running on numa 0 only:
> > 5.17-rc1 rc1 + chenyu rc1+chenyu+cls rc1+chenyu+cls-pingpong rc1+cls
> > Hmean 1 324.73 ( 0.00%) 330.96 * 1.92%* 358.97 * 10.54%* 376.05 * 15.80%* 378.01 * 16.41%*
> > Hmean 2 645.36 ( 0.00%) 643.13 * -0.35%* 710.78 * 10.14%* 744.34 * 15.34%* 754.63 * 16.93%*
> > Hmean 4 1302.09 ( 0.00%) 1297.11 * -0.38%* 1425.22 * 9.46%* 1484.92 * 14.04%* 1507.54 * 15.78%*
> > Hmean 8 2612.03 ( 0.00%) 2623.60 * 0.44%* 2843.15 * 8.85%* 2937.81 * 12.47%* 2982.57 * 14.19%*
> > Hmean 16 5307.12 ( 0.00%) 5304.14 * -0.06%* 5610.46 * 5.72%* 5763.24 * 8.59%* 5886.66 * 10.92%*
> > Hmean 32 9354.22 ( 0.00%) 9738.21 * 4.11%* 9360.21 * 0.06%* 9699.05 * 3.69%* 9908.13 * 5.92%*
> > Hmean 64 7240.35 ( 0.00%) 7210.75 * -0.41%* 6992.70 * -3.42%* 7321.52 * 1.12%* 7278.78 * 0.53%*
> > Hmean 128 6186.40 ( 0.00%) 6314.89 * 2.08%* 6166.44 * -0.32%* 6279.85 * 1.51%* 6187.85 ( 0.02%)
> > Hmean 256 9231.40 ( 0.00%) 9469.26 * 2.58%* 9134.42 * -1.05%* 9322.88 * 0.99%* 9448.61 * 2.35%*
> > Hmean 512 8907.13 ( 0.00%) 9130.46 * 2.51%* 9023.87 * 1.31%* 9276.19 * 4.14%* 9397.22 * 5.50%*
> >
> > > like rc1+cls, in some
> > > cases(256, 512 threads on numa0&1), it is even much better.
> > >
> > > Thanks
> > > Barry
prev parent reply other threads:[~2022-02-17 18:00 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-26 8:09 [PATCH v2 0/2] sched/fair: Wake task within the cluster when possible Yicong Yang
2022-01-26 8:09 ` [PATCH v2 1/2] sched: Add per_cpu cluster domain info and cpus_share_resources API Yicong Yang
2022-01-27 15:26 ` Gautham R. Shenoy
2022-01-26 8:09 ` [PATCH v2 2/2] sched/fair: Scan cluster before scanning LLC in wake-up path Yicong Yang
2022-01-27 1:14 ` Tim Chen
2022-01-27 2:02 ` Yicong Yang
2022-01-27 2:30 ` Tim Chen
2022-01-27 2:36 ` Tim Chen
2022-01-27 3:05 ` Yicong Yang
2022-01-27 15:41 ` Gautham R. Shenoy
2022-01-27 20:21 ` Barry Song
2022-01-28 7:13 ` Srikar Dronamraju
2022-01-27 18:40 ` Barry Song
2022-02-01 9:38 ` Srikar Dronamraju
2022-02-01 20:20 ` Barry Song
2022-02-04 7:33 ` Srikar Dronamraju
2022-02-04 10:28 ` Barry Song
2022-02-04 10:49 ` Barry Song
2022-02-04 17:41 ` Tim Chen
2022-02-05 17:16 ` Chen Yu
2022-02-06 0:26 ` Barry Song
2022-02-07 15:14 ` Gautham R. Shenoy
2022-02-08 5:42 ` Barry Song
2022-02-16 9:12 ` Barry Song
2022-02-16 9:19 ` Song Bao Hua (Barry Song)
2022-02-16 10:00 ` Yicong Yang
2022-02-17 18:00 ` Tim Chen [this message]
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