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From: "Ahmed S. Darwish" <a.darwish@linutronix.de>
To: Jonathan Schwender <schwenderjonathan@gmail.com>
Cc: jkacur@redhat.com, williams@redhat.com, linux-rt-users@vger.kernel.org
Subject: Re: rt-tests: cyclictest: Add option to specify main pid affinity
Date: Mon, 22 Feb 2021 17:20:35 +0100	[thread overview]
Message-ID: <YDPZ0xrEcsS5SfWh@lx-t490> (raw)
In-Reply-To: <20210222152833.8758-1-schwenderjonathan@gmail.com>

On Mon, Feb 22, 2021 at 04:28:30PM +0100, Jonathan Schwender wrote:
>
> Hi John,
>
> This patch adds the option --mainaffinity to specify the affinity of
> the main pid.
> This is mainly useful if you want to bind the main thread to a
> different (e.g. housekeeping ) CPU than the measurement threads.
>

Pardon my ignorance; can you please specify why is this important?
The measurement threads have an RT priority while the main thread is
SCHED_OTHER. So why would the cyclictest measurements really be affected
by the main thread (unless there's a preempt_rt bug)?

Do you also have any numbers showing different results with/without
"--mainaffinity"?

Thanks,

--
Ahmed S. Darwish

  parent reply	other threads:[~2021-02-22 16:22 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-22 15:28 rt-tests: cyclictest: Add option to specify main pid affinity Jonathan Schwender
2021-02-22 15:28 ` [PATCH 0/2] " Jonathan Schwender
2021-02-22 15:28 ` [PATCH 1/2] cyclictest: Move main pid setaffinity handling into a function Jonathan Schwender
2021-02-23  5:12   ` John Kacur
2021-02-22 15:28 ` [PATCH 2/2] cyclictest: Add --mainaffinity=[CPUSET] option Jonathan Schwender
2021-02-22 16:20 ` Ahmed S. Darwish [this message]
2021-02-22 17:05   ` rt-tests: cyclictest: Add option to specify main pid affinity Jonathan Schwender
2021-03-21 17:11   ` Jonathan Schwender
2021-03-23 16:51     ` John Kacur
2021-03-24  9:32     ` Ahmed S. Darwish
2021-03-29 14:37       ` Jonathan Schwender

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