From: Andi Kleen <ak@suse.de>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: torvalds@osdl.org, richard.brunner@amd.com,
linux-kernel@vger.kernel.org, akpm@osdl.org
Subject: Re: [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata
Date: Thu, 11 Sep 2003 16:24:21 +0200 [thread overview]
Message-ID: <20030911162421.419f4432.ak@suse.de> (raw)
In-Reply-To: <1063289641.2967.3.camel@dhcp23.swansea.linux.org.uk>
On Thu, 11 Sep 2003 15:14:02 +0100
Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
>
> There is *one* change needed. We shouldnt call is_prefetch unless the
> current CPU is an Athlon. That way its a performance improvement for
> PIV, and Athlon in general, fixes the bug and causes no fancy athlon
> fixup code for non AMD processors.
I considered that when writing the patch, but: is_prefetch is a single byte
memory access for something already in cache. Checking for an Athlon
CPU needs two memory accesses in boot_cpu_data at least (checking vendor
and model)
So checking for Athlon first would be actually more expensive for other CPUs.
The switch is left in the noise, gcc compiles it to very efficient code.
This ignores the possibility of a recursive fault in the __get_user, but these
are rather unlikely. Normal page-on-demand code faults are handled
before is_prefetch is reached.
-Andi
next prev parent reply other threads:[~2003-09-11 14:24 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-11 0:56 Update on AMD Athlon/Opteron/Athlon64 Prefetch Errata richard.brunner
2003-09-11 1:27 ` [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata Andi Kleen
2003-09-11 1:44 ` Andrew Morton
2003-09-11 1:47 ` Andi Kleen
2003-09-11 14:15 ` Jeff Garzik
2003-09-11 14:26 ` Andi Kleen
2003-09-11 14:34 ` Jeff Garzik
2003-09-11 14:58 ` Andi Kleen
2003-09-11 15:06 ` Jeff Garzik
2003-09-11 20:08 ` bill davidsen
2003-09-11 19:56 ` bill davidsen
2003-09-11 20:44 ` Alan Cox
2003-09-11 21:29 ` Mike Fedyk
2003-09-11 21:38 ` bill davidsen
2003-09-12 17:32 ` Eric W. Biederman
2003-09-12 17:56 ` Andi Kleen
2003-09-12 17:59 ` Jeff Garzik
2003-09-12 18:22 ` Adrian Bunk
2003-09-12 18:28 ` Andi Kleen
2003-09-12 18:39 ` Jeff Garzik
2003-09-12 18:45 ` Jeff Garzik
2003-09-12 18:48 ` Adrian Bunk
2003-09-12 19:07 ` Andi Kleen
2003-09-12 19:05 ` Martin Schlemmer
2003-09-12 19:30 ` Andi Kleen
2003-09-12 19:58 ` Martin Schlemmer
2003-09-12 20:00 ` Adrian Bunk
2003-09-15 0:15 ` bill davidsen
2003-09-14 23:51 ` bill davidsen
2003-09-14 23:49 ` bill davidsen
2003-09-14 23:47 ` bill davidsen
2003-09-15 1:02 ` Zwane Mwaikambo
2003-09-15 2:08 ` Nick Piggin
2003-09-15 3:55 ` Bill Davidsen
2003-09-15 7:45 ` Alan Cox
2003-09-15 12:11 ` Bill Davidsen
2003-09-15 13:48 ` Alan Cox
2003-09-15 18:50 ` Bill Davidsen
2003-09-12 18:03 ` Mike Fedyk
2003-09-11 13:54 ` Linus Torvalds
2003-09-11 14:01 ` Andi Kleen
2003-09-11 14:14 ` Dave Jones
2003-09-11 14:29 ` Andi Kleen
2003-09-11 14:14 ` Alan Cox
2003-09-11 14:24 ` Andi Kleen [this message]
2003-09-11 14:28 ` Dave Jones
2003-09-11 14:32 ` Andi Kleen
2003-09-11 20:14 ` bill davidsen
2003-09-11 16:58 ` Jamie Lokier
2003-09-11 17:05 ` Andi Kleen
2003-09-11 17:32 ` Jamie Lokier
2003-09-11 17:39 ` Andi Kleen
2003-09-11 17:48 ` Jamie Lokier
2003-09-11 18:18 ` Andi Kleen
2003-09-11 18:59 ` Jamie Lokier
2003-09-11 3:43 Nakajima, Jun
2003-09-11 4:03 ` Valdis.Kletnieks
[not found] <uqD5.3BI.3@gated-at.bofh.it>
2003-09-11 4:14 ` Andi Kleen
2003-09-11 4:58 ` dada1
2003-09-11 5:11 ` Andi Kleen
2003-09-11 5:58 ` dada1
2003-09-11 4:55 richard.brunner
2003-09-11 16:55 ` Jamie Lokier
2003-09-12 14:14 ` Martin Schlemmer
2003-09-11 17:09 richard.brunner
2003-09-11 17:14 richard.brunner
2003-09-11 17:17 richard.brunner
2003-09-13 16:54 ` Pavel Machek
2003-09-12 21:24 John Bradford
2003-09-15 6:32 John Bradford
2003-09-15 7:40 ` Alan Cox
2003-09-15 12:02 ` Bill Davidsen
2003-09-15 11:48 ` Bill Davidsen
2003-09-15 20:55 ` Adrian Bunk
2003-09-16 0:26 ` Bill Davidsen
2003-09-15 8:31 John Bradford
2003-09-15 8:32 ` Nick Piggin
2003-09-15 20:51 ` Adrian Bunk
2003-09-15 9:39 John Bradford
2003-09-15 9:58 ` Nick Piggin
2003-09-15 10:54 John Bradford
2003-09-15 10:52 ` Nick Piggin
2003-09-15 13:45 ` Alan Cox
2003-09-15 18:44 ` Bill Davidsen
2003-09-15 11:46 John Bradford
2003-09-15 12:38 ` Nick Piggin
2003-09-15 13:46 ` Chris Meadors
2003-09-15 14:00 ` Nick Piggin
2003-09-16 15:06 ` Bill Davidsen
2003-09-16 15:24 ` Nick Piggin
2003-09-15 12:28 Mikael Pettersson
2003-09-15 18:13 ` Bill Davidsen
2003-09-16 11:54 ` Jamie Lokier
2003-09-15 12:43 John Bradford
2003-09-15 18:21 ` Bill Davidsen
2003-09-15 14:21 John Bradford
2003-09-15 16:21 richard.brunner
2003-09-15 19:15 ` Bill Davidsen
2003-09-16 11:46 ` Jamie Lokier
2003-09-16 13:30 ` Dave Jones
2003-09-16 13:52 ` Bill Davidsen
2003-09-16 15:25 ` Timothy Miller
2003-09-16 16:53 ` Bill Davidsen
2003-09-16 17:22 ` Jamie Lokier
2003-09-16 17:23 ` Jamie Lokier
2003-09-18 7:43 ` Pavel Machek
2003-09-18 14:05 ` Dave Jones
2003-09-18 15:56 ` Jamie Lokier
2003-09-18 17:34 ` Bill Davidsen
[not found] <200309150632.h8F6WnHb000589@81-2-122-30.bradfords.org.uk.suse.lists.linux.kernel>
[not found] ` <1063611650.2674.1.camel@dhcp23.swansea.linux.org.uk.suse.lists.linux.kernel>
2003-09-15 18:29 ` Andi Kleen
2003-09-15 19:19 John Bradford
2003-09-15 19:34 John Bradford
2003-09-15 19:25 ` Bill Davidsen
2003-09-15 22:28 ` Alan Cox
2003-09-15 19:51 richard.brunner
2003-09-16 0:01 ` David Lang
2003-09-16 0:20 ` Bill Davidsen
2003-09-16 11:50 ` Jamie Lokier
2003-09-16 13:46 ` Bill Davidsen
2003-09-16 17:21 ` Jamie Lokier
2003-09-15 20:03 Nakajima, Jun
2003-09-15 20:20 Nakajima, Jun
2003-09-16 2:23 richard.brunner
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