From: Linus Torvalds <torvalds@osdl.org>
To: Andi Kleen <ak@suse.de>
Cc: Denis Vlasenko <vda@port.imtp.ilyichevsk.odessa.ua>,
linux-kernel@vger.kernel.org
Subject: Re: Semaphore assembly-code bug
Date: Sat, 30 Oct 2004 18:43:21 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.58.0410301831300.28839@ppc970.osdl.org> (raw)
In-Reply-To: <20041031003934.GA19396@wotan.suse.de>
On Sun, 31 Oct 2004, Andi Kleen wrote:
>
> Using the long stack setup code was found to be a significant
> win when enough registers were saved (several percent in real benchmarks)
> on K8 gcc.
For _what_?
Real applications, or SpecInt?
The fact is, SpecInt is not very interesting, because it has almost _zero_
icache footprint, and it has generally big repeat-rates, and to make
matters worse, you are allowed (and everybody does) warm up the caches by
running before you actually do the benchmark run.
_None_ of these are realistic for real life workloads.
> It speed up all function calls considerably because it
> eliminates several stalls for each function entry/exit.
.. it shaves off a few cycles in the cached case, yes.
> The popls will all depend on each other because of their implicied
> reference to esp.
Which is only true on moderately stupid CPU's. Two pop's don't _really_
depend on each other in any real sense, and there are CPU's that will
happily dual-issue them, or at least not stall in between (ie the pop's
will happily keep the memory unit 100% busy).
Linus
next prev parent reply other threads:[~2004-10-31 1:43 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <Pine.LNX.4.58.0410181540080.2287@ppc970.osdl.org.suse.lists.linux.kernel>
[not found] ` <417550FB.8020404@drdos.com.suse.lists.linux.kernel>
[not found] ` <1098218286.8675.82.camel@mentorng.gurulabs.com.suse.lists.linux.kernel>
[not found] ` <41757478.4090402@drdos.com.suse.lists.linux.kernel>
[not found] ` <20041020034524.GD10638@michonline.com.suse.lists.linux.kernel>
[not found] ` <1098245904.23628.84.camel@krustophenia.net.suse.lists.linux.kernel>
[not found] ` <1098247307.23628.91.camel@krustophenia.net.suse.lists.linux.kernel>
[not found] ` <Pine.LNX.4.61.0410200744310.10521@chaos.analogic.com.suse.lists.linux.kernel>
[not found] ` <Pine.LNX.4.61.0410290805570.11823@chaos.analogic.com.suse.lists.linux.kernel>
[not found] ` <Pine.LNX.4.58.0410290740120.28839@ppc970.osdl.org.suse.lists.linux.kernel>
[not found] ` <41826A7E.6020801@domdv.de.suse.lists.linux.kernel>
[not found] ` <Pine.LNX.4.61.0410291255400.17270@chaos.analogic.com.suse.lists.linux.kernel>
[not found] ` <Pine.LNX.4.58.0410291103000.28839@ppc970.osdl.org.suse.lists.linux.kernel>
[not found] ` <Pine.LNX.4.61.0410291631250.8616@twinlark.arctic.org.suse.lists.linux.kernel>
2004-10-30 2:04 ` Semaphore assembly-code bug Andi Kleen
[not found] ` <Pine.LNX.4.61.0410291316470.3945@chaos.analogic.com.suse.lists.linux.kernel>
[not found] ` <20041029175527.GB25764@redhat.com.suse.lists.linux.kernel>
[not found] ` <Pine.LNX.4.61.0410291416040.4844@chaos.analogic.com.suse.lists.linux.kernel>
[not found] ` <Pine.LNX.4.58.0410291133220.28839@ppc970.osdl.org.suse.lists.linux.kernel>
2004-10-30 2:13 ` Andi Kleen
2004-10-30 9:28 ` Denis Vlasenko
2004-10-30 17:53 ` Linus Torvalds
2004-10-30 21:00 ` Denis Vlasenko
2004-10-30 21:14 ` code bloat [was Re: Semaphore assembly-code bug] Lee Revell
2004-10-30 22:11 ` Denis Vlasenko
2004-10-30 22:25 ` Lee Revell
2004-10-31 14:06 ` Diego Calleja
2004-10-31 20:53 ` Z Smith
2004-10-31 23:35 ` Rogério Brito
2004-11-01 1:20 ` Z Smith
2004-11-01 14:48 ` Diego Calleja
2004-11-01 15:09 ` [OT] " Russell Miller
2004-10-30 22:27 ` Tim Hockin
2004-10-30 22:44 ` Jeff Garzik
2004-10-30 22:50 ` Tim Hockin
2004-10-31 20:15 ` Theodore Ts'o
2004-10-31 20:21 ` Jeff Garzik
2004-10-31 21:06 ` Jan Engelhardt
2004-11-01 11:27 ` Alan Cox
2004-11-01 13:40 ` Denis Vlasenko
2004-11-01 23:04 ` Alan Cox
2004-10-30 23:13 ` Denis Vlasenko
2004-10-30 22:45 ` Alan Cox
2004-10-31 1:21 ` Z Smith
2004-10-31 2:47 ` Jim Nelson
2004-10-31 15:19 ` Alan Cox
2004-10-31 20:18 ` Z Smith
2004-11-01 11:05 ` Alan Cox
2004-10-30 23:20 ` [OT] " Lee Revell
2004-10-30 22:52 ` Alan Cox
2004-10-31 1:09 ` Ken Moffat
2004-10-31 2:42 ` Tim Connors
2004-10-31 4:45 ` Paul
2004-10-31 14:44 ` Alan Cox
2004-10-31 0:48 ` Andi Kleen
2004-10-30 23:28 ` Tim Hockin
2004-10-31 2:04 ` Michael Clark
2004-10-31 6:49 ` Jan Engelhardt
2004-10-31 21:09 ` Z Smith
2004-10-31 21:13 ` Jan Engelhardt
2004-10-31 21:48 ` Z Smith
2004-11-01 11:29 ` Alan Cox
2004-11-01 12:36 ` Jan Engelhardt
2004-11-01 15:17 ` Lee Revell
2004-11-01 16:56 ` Kristian Høgsberg
2004-10-31 6:37 ` Jan Engelhardt
2004-10-31 0:39 ` Semaphore assembly-code bug Andi Kleen
2004-10-31 1:43 ` Linus Torvalds [this message]
2004-10-31 2:04 ` Andi Kleen
2004-10-18 22:45 Linux v2.6.9 Linus Torvalds
2004-10-19 17:38 ` Linux v2.6.9 and GPL Buyout Jeff V. Merkey
2004-10-19 20:38 ` Dax Kelson
2004-10-19 20:09 ` Jeff V. Merkey
2004-10-20 3:45 ` Ryan Anderson
2004-10-20 4:18 ` Lee Revell
2004-10-20 4:41 ` Lee Revell
2004-10-20 11:49 ` Richard B. Johnson
2004-10-29 12:12 ` Semaphore assembly-code bug linux-os
2004-10-29 14:46 ` Linus Torvalds
2004-10-29 15:11 ` Andi Kleen
2004-10-29 18:18 ` Linus Torvalds
2004-10-29 18:35 ` Richard Henderson
2004-10-29 16:06 ` Andreas Steinmetz
2004-10-29 17:08 ` linux-os
2004-10-29 18:06 ` Linus Torvalds
2004-10-29 18:39 ` linux-os
2004-10-29 19:12 ` Linus Torvalds
2004-11-01 1:31 ` linux-os
2004-11-01 5:49 ` Linus Torvalds
2004-11-01 20:23 ` dean gaudet
2004-11-01 20:52 ` linux-os
2004-11-01 21:23 ` dean gaudet
2004-11-01 22:22 ` linux-os
2004-11-01 21:40 ` Linus Torvalds
2004-11-01 21:46 ` Linus Torvalds
2004-11-02 15:02 ` linux-os
2004-11-02 16:02 ` Linus Torvalds
2004-11-02 16:06 ` Linus Torvalds
2004-11-02 16:51 ` linux-os
2004-11-01 22:16 ` linux-os
2004-11-01 22:26 ` Linus Torvalds
2004-11-01 23:14 ` linux-os
2004-11-01 23:42 ` Linus Torvalds
2004-11-03 1:52 ` Horst von Brand
2004-11-03 21:24 ` Bill Davidsen
2004-11-02 6:37 ` Chris Friesen
2004-10-29 18:58 ` Andreas Steinmetz
2004-10-29 19:15 ` Linus Torvalds
2004-10-29 19:40 ` Andreas Steinmetz
2004-10-29 19:56 ` Linus Torvalds
2004-10-29 22:07 ` Jeff Garzik
2004-10-29 23:50 ` dean gaudet
2004-10-30 0:15 ` Linus Torvalds
2004-10-29 23:37 ` dean gaudet
2004-10-29 17:22 ` linux-os
2004-10-29 17:55 ` Richard Henderson
2004-10-29 18:17 ` linux-os
2004-10-29 18:42 ` Linus Torvalds
2004-10-29 18:54 ` Linus Torvalds
2004-10-30 3:35 ` Jeff Garzik
2004-10-29 19:20 ` Linus Torvalds
2004-10-29 19:26 ` Linus Torvalds
2004-10-29 21:03 ` Linus Torvalds
2004-10-29 17:57 ` Richard Henderson
2004-10-29 18:37 ` Gabriel Paubert
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