From: Mel Gorman <mgorman@suse.de>
To: "Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
"vincent.guittot@linaro.org" <vincent.guittot@linaro.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"dietmar.eggemann@arm.com" <dietmar.eggemann@arm.com>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"bsegall@google.com" <bsegall@google.com>,
"valentin.schneider@arm.com" <valentin.schneider@arm.com>,
"juri.lelli@redhat.com" <juri.lelli@redhat.com>,
"bristot@redhat.com" <bristot@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"guodong.xu@linaro.org" <guodong.xu@linaro.org>,
yangyicong <yangyicong@huawei.com>,
tangchengchang <tangchengchang@huawei.com>,
Linuxarm <linuxarm@huawei.com>
Subject: Re: [PATCH] sched: fair: don't depend on wake_wide if waker and wakee are already in same LLC
Date: Tue, 1 Jun 2021 08:59:18 +0100 [thread overview]
Message-ID: <20210601075918.GP3672@suse.de> (raw)
In-Reply-To: <07e4ba63a19c451ab47e6a636c400f4a@hisilicon.com>
On Mon, May 31, 2021 at 10:21:55PM +0000, Song Bao Hua (Barry Song) wrote:
> The benchmark of tbenchs is still positive:
>
> tbench4
>
> 5.13-rc4 5.13-rc4
> disable-llc-wakewide/
>
> Hmean 1 514.87 ( 0.00%) 505.17 * -1.88%*
> Hmean 2 914.45 ( 0.00%) 918.45 * 0.44%*
> Hmean 4 1483.81 ( 0.00%) 1485.38 * 0.11%*
> Hmean 8 2211.62 ( 0.00%) 2236.02 * 1.10%*
> Hmean 16 2129.80 ( 0.00%) 2450.81 * 15.07%*
> Hmean 32 5098.35 ( 0.00%) 5085.20 * -0.26%*
> Hmean 64 4797.62 ( 0.00%) 4801.34 * 0.08%*
> Hmean 80 4802.89 ( 0.00%) 4780.40 * -0.47%*
>
> I guess something which work across several LLC domains
> cause performance regression.
>
> I wonder how your test will be like if you pin the testing
> to CPUs within one LLC?
>
While I could do this, what would be the benefit? Running within one LLC
would be running the test in one small fraction of the entire machine as
the machine has multiple LLCs per NUMA node. A patch dealing with how the
scheduler works with respect to LLC should take different configurations
into consideration as best as possible.
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2021-06-01 7:59 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-26 9:10 [PATCH] sched: fair: don't depend on wake_wide if waker and wakee are already in same LLC Barry Song
2021-05-26 12:15 ` Peter Zijlstra
2021-05-26 21:38 ` Song Bao Hua (Barry Song)
2021-05-27 12:14 ` Mel Gorman
2021-05-31 22:21 ` Song Bao Hua (Barry Song)
2021-06-01 7:59 ` Mel Gorman [this message]
2021-06-01 8:09 ` Song Bao Hua (Barry Song)
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