From: Pavel Machek <pavel@suse.cz>
To: Jeff Garzik <jgarzik@pobox.com>
Cc: Manfred Spraul <manfred@colorfullife.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] add likely around access_ok for uaccess
Date: Tue, 16 Sep 2003 22:59:31 +0200 [thread overview]
Message-ID: <20030916205931.GF1205@elf.ucw.cz> (raw)
In-Reply-To: <20030916205545.GA14153@gtf.org>
Hi!
> > > while trying to figure out why sysv msg is around 30% slower than pipes
> > > for data transfers I noticed that gcc's autodetection (3.2.2) guesses
> > > the "if(access_ok())" tests in uaccess.h wrong and puts the error memset
> > > into the direct path and the copy out of line.
> > >
> > > The attached patch adds likely to the tests - any objections? What about
> > > the archs except i386?
> >
> > How much speedup did you gain?
>
> How much can it hurt?
The change is obviously okay, I just wanted to know... If it gains 30%
on sysv messages.. that would be pretty big surprise.
Pavel
--
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]
next prev parent reply other threads:[~2003-09-16 20:59 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-14 11:17 [PATCH] add likely around access_ok for uaccess Manfred Spraul
2003-09-14 19:30 ` Andrew Morton
2003-09-14 19:45 ` Manfred Spraul
2003-09-14 19:48 ` Manfred Spraul
2003-09-14 20:00 ` Andrew Morton
2003-09-15 22:59 ` David S. Miller
2003-09-16 19:49 ` Pavel Machek
2003-09-16 20:55 ` Jeff Garzik
2003-09-16 20:59 ` Pavel Machek [this message]
2003-09-17 16:57 ` Manfred Spraul
[not found] <vD5l.6Wt.19@gated-at.bofh.it>
2003-09-14 16:49 ` Andi Kleen
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