From: Andrew Morton <akpm@zip.com.au>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: Andi Kleen <ak@suse.de>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] syscall latency improvement #1
Date: Fri, 25 Jan 2002 18:10:12 -0800 [thread overview]
Message-ID: <3C521003.991A690B@zip.com.au> (raw)
In-Reply-To: <p73y9il7vlr.fsf@oldwotan.suse.de> <Pine.LNX.4.33.0201251741430.16917-100000@penguin.transmeta.com>
Linus Torvalds wrote:
>
> It should be eminently testable. Just remove the cli from the standard
> kernel, and do before-and-after tests.
>
#include <unistd.h>
main()
{
int i = 100 * 1000 * 1000;
while (i--)
getpid();
}
With cli:
./a.out 22.05s user 15.31s system 99% cpu 37.361 total
without cli:
./a.out 18.29s user 17.42s system 99% cpu 35.731 total
That's 4.6%. Intel P3.
It's also 306 cycles per iteration. So the cli added 14 cycles.
-
next prev parent reply other threads:[~2002-01-26 2:18 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
[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 ` [PATCH] syscall latency improvement #1 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 [this message]
2002-01-26 3:06 ` Robert Love
2002-01-26 3:20 ` Robert Love
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 0:53 ` Rusty Russell
2002-01-29 12:54 ` Pavel Machek
2002-01-29 12:59 ` Denis Vlasenko
2002-01-26 18:39 ` Alan Cox
2002-01-27 19:59 ` Jamie Lokier
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