From: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
To: Richard Kennedy <richard@rsk.demon.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@elte.hu>, lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sched: reorder root_domain to remove 64 bit alignment padding
Date: Fri, 15 Jul 2011 15:59:36 -0300 [thread overview]
Message-ID: <20110715185936.GA22168@khazad-dum.debian.net> (raw)
In-Reply-To: <1310728994.1977.15.camel@castor.rsk>
On Fri, 15 Jul 2011, Richard Kennedy wrote:
> On Fri, 2011-07-15 at 12:44 +0200, Peter Zijlstra wrote:
> > On Fri, 2011-07-15 at 11:41 +0100, Richard Kennedy wrote:
> > > Reorder root_domain to remove 8 bytes of alignment padding on 64 bit
> > > builds, this shrinks the size from 1736 to 1728 bytes, therefore using
> > > one fewer cachelines.
> >
> > depends a bit on how insane struct cpupri is, but yeah, good compaction.
> > Thanks!
>
> Thanks Peter,
>
> argh -- I hadn't spotted that cpupri used NR_CPUS and was so variable in
> size. I guess there won't be much benefit then, as the distros seem to
> always set NR_CPUS to some insanely huge value ;)
There will be, for those who _do_ care about performance (and thus have sane
NR_CPUS for their boxes, among other things). Please don't be discouraged
over this.
--
"One disk to rule them all, One disk to find them. One disk to bring
them all and in the darkness grind them. In the Land of Redmond
where the shadows lie." -- The Silicon Valley Tarot
Henrique Holschuh
next prev parent reply other threads:[~2011-07-15 18:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-15 10:41 [PATCH] sched: reorder root_domain to remove 64 bit alignment padding Richard Kennedy
2011-07-15 10:44 ` Peter Zijlstra
2011-07-15 11:23 ` Richard Kennedy
2011-07-15 18:59 ` Henrique de Moraes Holschuh [this message]
2011-07-21 18:30 ` [tip:sched/core] sched: Reorder " tip-bot for Richard Kennedy
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=20110715185936.GA22168@khazad-dum.debian.net \
--to=hmh@hmh.eng.br \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=peterz@infradead.org \
--cc=richard@rsk.demon.co.uk \
/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;
as well as URLs for NNTP newsgroup(s).