From: Phil Auld <pauld@redhat.com>
To: Joseph Salisbury <joseph.salisbury@oracle.com>
Cc: peterz@infradead.org, mingo@kernel.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
Steven Rostedt <rostedt@goodmis.org>,
bsegall@google.com, mgorman@suse.de, vschneid@redhat.com,
linux-kernel@vger.kernel.org
Subject: Re: [REGRESSION] sched/fair: Add lag based placement
Date: Wed, 13 Nov 2024 13:19:30 -0500 [thread overview]
Message-ID: <20241113181930.GD402105@pauld.westford.csb> (raw)
In-Reply-To: <58289b1c-8a56-4607-8632-d36aef1fc5dd@oracle.com>
Hi,
On Wed, Nov 13, 2024 at 01:03:00PM -0500 Joseph Salisbury wrote:
> Hello,
>
> During performance testing, we found a regression of ~9% performance with
> the TPCC benchmark. This performance regression was introduced in
> v6.6-rc1. After a bisect, the following commit was identified as the cause
> of the regression:
>
> 86bfbb7ce4f6 ("sched/fair: Add lag based placement")
>
> I was hoping to get some feedback from the scheduler folks. Do you think
> gathering any additional data will help diagnose this issue? Are there any
> tunable options that can changed to see how performance is affected?
>
You can try turning off the PLACE_LAG sched feature:
echo NO_PLACE_LAG > /sys/kernel/debug/sched/features
It's not what I'd call a tunable but it would allow you to test w/o it and
see what it does. It should allow you to switch back and forth easily for
testing.
Cheers,
Phil
>
> Thanks,
>
> Joe
>
>
>
>
>
>
>
>
--
next prev parent reply other threads:[~2024-11-13 18:19 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-13 18:03 Joseph Salisbury
2024-11-13 18:19 ` Phil Auld [this message]
2024-11-13 18:22 ` [External] : " Joseph Salisbury
2024-11-13 18:33 ` Joseph Salisbury
2024-11-14 19:50 ` [External] : " Joseph Salisbury
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