From: Rene Herman <rene.herman@keyaccess.nl>
To: linux@horizon.com
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [RFT] Port 0x80 I/O speed
Date: Wed, 12 Dec 2007 15:48:01 +0100 [thread overview]
Message-ID: <475FF4A1.4020401@keyaccess.nl> (raw)
In-Reply-To: <20071212112049.17891.qmail@science.horizon.com>
On 12-12-07 12:20, linux@horizon.com wrote:
> Here are a variety of machines:
Thanks much for all! Collecting all data now...
> With -O2, the cycle counts come out (before division) as
> out: 0xFFFFFFFFFFEA6F4F
> in: 0xFFFFFFFFFCE68BB6
> I think the "A" constraint doesn't work quite the same in
> 64-bit code. The compiler seems to be using %rdx rather than
> %edx:%eax.
Yes indeed, that tripped me up. Have been using the "=A" locally for a while
for similar timing tests. Will use a manual "=a" (lo), "=d" (hi) I guess for
amd64 compatibility from now on.
If I'd care deeply I'd probably categorize this as a backwards compatibility
bug in GCC though. Things were probably never guaranteed but they certainly
worked that way...
Rene.
next prev parent reply other threads:[~2007-12-12 14:49 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-12 11:20 [RFT] Port 0x80 I/O speed linux
2007-12-12 12:35 ` Paolo Ornati
2007-12-12 14:48 ` Rene Herman [this message]
[not found] <9A0cz-7xy-13@gated-at.bofh.it>
[not found] ` <9A0cz-7xy-11@gated-at.bofh.it>
[not found] ` <9A4pU-69z-15@gated-at.bofh.it>
2007-12-14 14:08 ` James Kosin
[not found] <9zmRR-3pA-25@gated-at.bofh.it>
2007-12-13 16:27 ` James Kosin
2007-12-13 22:07 ` Rene Herman
2007-12-13 22:30 ` Jesper Juhl
2007-12-13 22:37 ` Rene Herman
-- strict thread matches above, loose matches on Subject: below --
2007-12-12 5:06 Chris Holvenstot
2007-12-11 23:31 Rene Herman
2007-12-11 23:40 ` Maxim Levitsky
2007-12-11 23:44 ` Rene Herman
2007-12-12 0:14 ` Maxim Levitsky
2007-12-12 0:27 ` Rene Herman
2007-12-11 23:43 ` Alejandro Riveira Fernández
2007-12-11 23:51 ` Rene Herman
2007-12-12 0:09 ` Alejandro Riveira Fernández
2007-12-12 0:16 ` Rene Herman
2007-12-12 11:43 ` Alejandro Riveira Fernández
2007-12-12 21:02 ` H. Peter Anvin
[not found] ` <Pine.LNX.4.61.0712120753210.4443@chaos.analogic.com>
2007-12-12 13:20 ` Rene Herman
2007-12-12 13:23 ` linux-os (Dick Johnson)
2007-12-11 23:55 ` Nigel Cunningham
2007-12-12 0:01 ` Rene Herman
2007-12-12 2:07 ` Nigel Cunningham
2007-12-12 1:19 ` Alistair John Strachan
2007-12-12 1:28 ` Randy Dunlap
2007-12-12 1:40 ` Mike Lampard
2007-12-12 5:23 ` Kyle McMartin
2007-12-12 7:18 ` Rene Herman
2007-12-13 2:41 ` H. Peter Anvin
2007-12-12 19:25 ` H. Peter Anvin
2007-12-12 19:32 ` Andi Kleen
2007-12-12 19:43 ` H. Peter Anvin
2007-12-12 8:17 ` Paolo Ornati
2007-12-12 8:38 ` Edwin de Caluwé
2007-12-12 8:35 ` Dave Young
2007-12-12 8:48 ` Jiri Slaby
2007-12-12 11:25 ` Jiri Slaby
2007-12-12 15:50 ` Rene Herman
2007-12-12 15:53 ` Rene Herman
2007-12-12 18:44 ` H. Peter Anvin
2007-12-12 19:19 ` Rene Herman
2007-12-13 15:19 ` Jiri Slaby
2007-12-12 8:59 ` Juergen Beisert
2007-12-12 14:30 ` Rene Herman
2007-12-12 15:12 ` Juergen Beisert
2007-12-12 9:55 ` Luciano Rocha
2007-12-12 9:57 ` Romano Giannetti
2007-12-12 16:27 ` Rene Herman
2007-12-12 10:28 ` Peter Zijlstra
2007-12-12 10:34 ` Dave Haywood
2007-12-12 11:57 ` Ville Syrjälä
2007-12-13 16:42 ` Ville Syrjälä
2007-12-12 16:16 ` John Stoffel
2007-12-12 16:39 ` Olivér Pintér
2007-12-12 16:53 ` Ondrej Zary
2007-12-12 17:00 ` H. Peter Anvin
2007-12-12 16:59 ` Cyrill Gorcunov
2007-12-12 17:27 ` Török Edwin
2007-12-12 18:54 ` David P. Reed
2007-12-12 18:39 ` SL Baur
2007-12-12 19:06 ` Rene Herman
2007-12-12 21:32 ` Jesper Juhl
2007-12-12 23:54 ` Jan Engelhardt
2007-12-13 0:13 ` Jan Engelhardt
2007-12-13 2:06 ` H. Peter Anvin
2007-12-22 22:27 ` Bauke Jan Douma
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