From: Jamie Lokier <lk@tantalophile.demon.co.uk>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Linus Torvalds <torvalds@transmeta.com>,
David Howells <dhowells@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] syscall latency improvement #1
Date: Sun, 27 Jan 2002 19:59:32 +0000 [thread overview]
Message-ID: <20020127195932.H4818@kushida.apsleyroad.org> (raw)
In-Reply-To: <Pine.LNX.4.33.0201251626490.2042-100000@penguin.transmeta.com> <E16UXjj-0005su-00@the-village.bc.nu>
In-Reply-To: <E16UXjj-0005su-00@the-village.bc.nu>; from alan@lxorguk.ukuu.org.uk on Sat, Jan 26, 2002 at 06:39:35PM +0000
Alan Cox wrote:
> > NOTE! There are potentially other ways to do all of this, _without_ losing
> > atomicity. For example, you can move the "flags" value into the slot saved
> > for the CS segment (which, modulo vm86, will always be at a constant
> > offset on the stack), and make CS=0 be the work flag. That will cause the
> > CPU to trap atomically at the "iret".
>
> Is the test even needed. Suppose we instead patch the return stack if we
> set need_resched/sigpending, and do it on the rare occassion we set the
> value.
Yes, that's what you'll find in one of Ingo Molnar's low latency patches.
-- Jamie
next prev parent reply other threads:[~2002-01-27 20:04 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-25 18:54 David Howells
2002-01-25 22:35 ` Robert Love
2002-01-26 10:07 ` Nigel Gamble
2002-01-25 23:07 ` Paul Mackerras
2002-01-26 0:39 ` Linus Torvalds
2002-01-26 0:57 ` Andrew Morton
2002-01-26 1:20 ` Linus Torvalds
2002-01-26 4:00 ` Jamie Lokier
2002-01-28 14:18 ` Denis Vlasenko
2002-01-28 10:30 ` Andrew Morton
2002-01-28 15:28 ` Jeff Dike
2002-01-29 12:54 ` Pavel Machek
2002-01-29 12:59 ` Denis Vlasenko
2002-02-21 7:10 ` Cameron Simpson
2002-01-29 0:53 ` [PATCH] " Rusty Russell
2002-01-26 18:39 ` Alan Cox
2002-01-27 19:59 ` Jamie Lokier [this message]
[not found] <18993.1011984842@warthog.cambridge.redhat.com.suse.lists.linux.kernel>
[not found] ` <Pine.LNX.4.33.0201251626490.2042-100000@penguin.transmeta.com.suse.lists.linux.kernel>
2002-01-26 1:24 ` Andi Kleen
2002-01-26 1:53 ` Linus Torvalds
2002-01-26 2:03 ` Andi Kleen
2002-01-26 2:14 ` Linus Torvalds
2002-01-26 2:26 ` Andi Kleen
2002-01-26 2:39 ` Dave Jones
2002-01-26 2:53 ` Davide Libenzi
2002-01-26 2:10 ` Andrew Morton
2002-01-26 3:20 ` Robert Love
2002-01-26 3:06 ` Robert Love
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=20020127195932.H4818@kushida.apsleyroad.org \
--to=lk@tantalophile.demon.co.uk \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=dhowells@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=torvalds@transmeta.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