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From: "H. Peter Anvin" <hpa@zytor.com>
To: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [RFC] div64_64 support
Date: Mon, 26 Feb 2007 17:20:34 -0800	[thread overview]
Message-ID: <45E38762.5040407@zytor.com> (raw)
In-Reply-To: <20070226132834.70514f19@freekitty>

Stephen Hemminger wrote:
> 
> Hmm. Those are the GCC internal versions, that are picked up but
> doing divide in place. Do we want to allow general 64 bit in kernel to
> be easily used? It could cause sloppy slow code, but it would look
> cleaner.
> 

... and it would handle datatypes which may be architecture-dependent a 
lot cleaner.

I thought the motivation for div64() was that a 64:32->32 divide could 
be done a lot faster on a number of platforms (including the important 
x86) than a generic 64:64->64 divide, but gcc doesn't handle the 
devolution automatically -- there is no such libgcc function.

	-hpa

  reply	other threads:[~2007-02-27  1:21 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-24  1:05 Stephen Hemminger
2007-02-24 16:19 ` Sami Farin
2007-02-26 19:28   ` Stephen Hemminger
2007-02-26 19:39     ` David Miller
2007-02-26 20:09 ` Jan Engelhardt
2007-02-26 21:28   ` Stephen Hemminger
2007-02-27  1:20     ` H. Peter Anvin [this message]
2007-02-27  3:45       ` Segher Boessenkool
2007-02-26 22:31   ` Stephen Hemminger
2007-02-26 23:02     ` Jan Engelhardt
2007-02-26 23:44       ` Stephen Hemminger
2007-02-27  0:05         ` Jan Engelhardt
2007-02-27  0:07           ` Stephen Hemminger
2007-02-27  0:14             ` Jan Engelhardt
2007-02-27  6:21     ` Dan Williams
2007-03-03  2:31     ` Andi Kleen
2007-03-05 23:57       ` Stephen Hemminger
2007-03-06  0:25         ` David Miller
2007-03-06 13:36           ` Andi Kleen
2007-03-06 14:04           ` [RFC] div64_64 support II Andi Kleen
2007-03-06 17:43             ` Dagfinn Ilmari Mannsåker
2007-03-06 18:25               ` David Miller
2007-03-06 18:48             ` H. Peter Anvin
2007-03-06 13:34         ` [RFC] div64_64 support Andi Kleen
2007-03-06 14:19           ` Eric Dumazet
2007-03-06 14:45             ` Andi Kleen
2007-03-06 15:10               ` Roland Kuhn
2007-03-06 18:29                 ` Stephen Hemminger
2007-03-06 19:48                   ` Andi Kleen
2007-03-06 20:04                     ` Stephen Hemminger
2007-03-06 21:53                   ` Sami Farin
2007-03-06 22:24                     ` Sami Farin
2007-03-07  0:00                       ` Stephen Hemminger
2007-03-07  0:05                         ` David Miller
2007-03-07  0:05                         ` Sami Farin
2007-03-07 16:11                       ` Chuck Ebbert
2007-03-07 18:32                         ` Sami Farin
2007-03-08 18:23                       ` asm volatile [Was: [RFC] div64_64 support] Sami Farin
2007-03-08 22:01                         ` asm volatile David Miller
2007-03-06 21:58                   ` [RFC] div64_64 support David Miller
2007-03-06 22:47                     ` [PATCH] tcp_cubic: faster cube root Stephen Hemminger
2007-03-06 22:58                       ` cube root benchmark code Stephen Hemminger
2007-03-07  6:08                         ` Update to " Willy Tarreau
2007-03-08  1:07                           ` [PATCH] tcp_cubic: use 32 bit math Stephen Hemminger
2007-03-08  2:55                             ` David Miller
2007-03-08  3:10                               ` Stephen Hemminger
2007-03-08  3:51                                 ` David Miller
2007-03-10 11:48                                   ` Willy Tarreau
2007-03-12 21:11                                     ` Stephen Hemminger
2007-03-13 20:50                                       ` Willy Tarreau
2007-03-21 18:54                                         ` Stephen Hemminger
2007-03-21 19:15                                           ` Willy Tarreau
2007-03-21 19:58                                             ` Stephen Hemminger
2007-03-21 20:15                                             ` [PATCH 1/2] div64_64 optimization Stephen Hemminger
2007-03-21 20:17                                               ` [PATCH 2/2] tcp: cubic optimization Stephen Hemminger
2007-03-22 19:11                                                 ` David Miller
2007-03-22 19:11                                               ` [PATCH 1/2] div64_64 optimization David Miller
2007-03-08  4:16                                 ` [PATCH] tcp_cubic: use 32 bit math Willy Tarreau
2007-03-07  4:20                       ` [PATCH] tcp_cubic: faster cube root David Miller
2007-03-07 12:12                         ` Andi Kleen
2007-03-07 19:33                           ` David Miller
2007-03-06 18:50               ` [RFC] div64_64 support H. Peter Anvin

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