From: Thomas Gleixner <tglx@linutronix.de>
To: Dimitri Sivanich <sivanich@sgi.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] specific do_timer_cpu value for nohz off mode
Date: Wed, 15 Feb 2012 15:16:34 +0100 (CET) [thread overview]
Message-ID: <alpine.LFD.2.02.1202151512420.2794@ionos> (raw)
In-Reply-To: <20111108191149.GA7236@sgi.com>
On Tue, 8 Nov 2011, Dimitri Sivanich wrote:
>
> Allow manual override of the tick_do_timer_cpu.
>
> While not necessarily harmful, doing jiffies updates on an application cpu
> does cause some extra overhead that HPC benchmarking people notice. They
> prefer to have OS activity isolated to certain cpus. They like reproducibility
> of results, and having jiffies updates bouncing around introduces variability.
I really wonder about this changelog. The only case where jiffies
updates bounces around is the NOHZ case. In all other modes (periodic
or highres) the boot cpu gets the do_timer() duty and it's never
assigned to any other cpu.
So what's the point of this exercise? Moving it away from CPU0 for
acedemic reasons or what?
Thanks,
tglx
next prev parent reply other threads:[~2012-02-15 14:16 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-08 19:11 Dimitri Sivanich
2011-11-23 0:08 ` Andrew Morton
2011-11-30 15:29 ` Dimitri Sivanich
2011-12-01 0:11 ` Andrew Morton
2011-12-01 0:16 ` Andrew Morton
2011-12-01 2:07 ` Dimitri Sivanich
2011-12-01 2:13 ` Andrew Morton
2011-12-01 16:37 ` Dimitri Sivanich
2011-12-01 22:56 ` Andrew Morton
2011-12-02 20:14 ` Dimitri Sivanich
2011-12-02 20:22 ` Dimitri Sivanich
2011-12-02 22:42 ` Thomas Gleixner
2011-12-01 2:06 ` Dimitri Sivanich
2011-12-01 2:12 ` Andrew Morton
2011-12-01 2:34 ` Dimitri Sivanich
2011-12-01 2:38 ` Andrew Morton
2012-01-15 13:46 ` Mike Galbraith
2012-01-15 14:04 ` Mike Galbraith
2012-01-15 14:23 ` Mike Galbraith
2012-01-25 11:27 ` Mike Galbraith
2012-02-15 14:16 ` Thomas Gleixner [this message]
2012-02-15 14:37 ` Dimitri Sivanich
2012-02-15 14:52 ` Thomas Gleixner
2012-02-15 15:34 ` Dimitri Sivanich
2012-02-15 20:36 ` Thomas Gleixner
2012-02-16 14:59 ` Dimitri Sivanich
2013-03-19 17:03 ` [PATCH][RFC] " Jiri Bohac
-- strict thread matches above, loose matches on Subject: below --
2011-08-17 16:07 [PATCH] " Dimitri Sivanich
2011-08-17 16:47 ` Thomas Gleixner
2011-08-23 19:56 ` Dimitri Sivanich
2011-09-02 8:19 ` Thomas Gleixner
2011-09-02 19:29 ` Dimitri Sivanich
2011-09-02 19:57 ` Thomas Gleixner
2011-09-02 20:39 ` Dimitri Sivanich
2011-08-03 19:57 Dimitri Sivanich
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=alpine.LFD.2.02.1202151512420.2794@ionos \
--to=tglx@linutronix.de \
--cc=linux-kernel@vger.kernel.org \
--cc=sivanich@sgi.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Powered by JetHome