From: Paul Jackson <pj@sgi.com>
To: Linus Torvalds <torvalds@osdl.org>
Cc: mingo@elte.hu, pwil3058@bigpond.net.au, akpm@osdl.org,
linux-kernel@vger.kernel.org
Subject: Re: [patch, 2.6.10-rc2] sched: fix ->nr_uninterruptible handling bugs
Date: Thu, 27 Jan 2005 16:53:30 -0800 [thread overview]
Message-ID: <20050127165330.6f388054.pj@sgi.com> (raw)
In-Reply-To: <Pine.LNX.4.58.0411161509190.2222@ppc970.osdl.org>
A long time ago, Linus wrote:
> An atomic op is pretty much as expensive as a spinlock/unlock pair on x86.
> Not _quite_, but it's pretty close.
Are both read and modify atomic ops relatively expensive on some CPUs,
or is it just modify atomic ops?
(Ignoring for this question the possibility that a mix of read and
modify ops could heat up a cache line on multiprocessor systems, and
focusing for the moment just on the CPU internals ...)
--
I won't rest till it's the best ...
Programmer, Linux Scalability
Paul Jackson <pj@sgi.com> 1.650.933.1373, 1.925.600.0401
next prev parent reply other threads:[~2005-01-28 0:56 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-11-16 11:32 [patch, 2.6.10-rc2] sched: fix ->nr_uninterruptible handling bugs Ingo Molnar
2004-11-16 22:19 ` Peter Williams
2004-11-16 23:28 ` Ingo Molnar
2004-11-16 23:10 ` Linus Torvalds
2004-11-17 10:26 ` Ingo Molnar
2004-11-17 15:52 ` Linus Torvalds
2004-11-18 16:21 ` Ingo Molnar
2005-01-28 0:53 ` Paul Jackson [this message]
2005-01-28 1:06 ` Linus Torvalds
2005-01-28 2:14 ` Paul Jackson
2005-01-28 4:28 ` Ingo Molnar
2005-01-28 5:18 ` Paul Jackson
2005-01-28 6:01 ` Andi Kleen
2004-11-16 23:48 ` Peter Williams
2004-11-16 22:49 ` Nick Piggin
2004-11-16 23:03 ` Nick Piggin
2004-11-16 23:32 ` Peter Williams
2004-11-16 23:37 ` Nick Piggin
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=20050127165330.6f388054.pj@sgi.com \
--to=pj@sgi.com \
--cc=akpm@osdl.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=pwil3058@bigpond.net.au \
--cc=torvalds@osdl.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.