From: linux@horizon.com
To: dhowells@redhat.com
Cc: linux@horizon.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation
Date: 16 Dec 2005 13:03:23 -0500 [thread overview]
Message-ID: <20051216180323.8637.qmail@science.horizon.com> (raw)
In-Reply-To: <19559.1134746682@warthog.cambridge.redhat.com>
> Which would be totally pointless.
>
> If you have LL/SC, then the odds are you _don't_ have CMPXCHG, and that
> CMPXCHG is implemented using LL/SC, so what you end up with is:
Ah, you're not quite understanding what I wrote, but I see the confusion.
I took "turned into" to mean "ported to an architecture with the
other primitive", and intended it that when I said "turned back".
That's obviously pointless if you're emulating one with the other.
The point I was making is that, for any LL/SC sequence, there is an
exactly analagous LD/CMPXCHG version, so you never have to have more
CMPXCHGs than SCs.
This was an attempt to disprove your claim that LL/SC was better by more
than a very small factor.
It it possible to optimize for the contention-free case and do away
with the initial load, at the expense of an additional CMPXCHG in the
failure case.
next prev parent reply other threads:[~2005-12-16 18:03 UTC|newest]
Thread overview: 227+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-16 12:49 [PATCH 1/19] MUTEX: Introduce simple mutex implementation linux
2005-12-16 15:24 ` David Howells
2005-12-16 18:03 ` linux [this message]
-- strict thread matches above, loose matches on Subject: below --
2005-12-15 17:45 Luck, Tony
2005-12-15 18:00 ` David Howells
2005-12-15 18:48 ` James Bottomley
2005-12-15 20:38 ` Jeff Dike
2005-12-15 23:45 ` Stephen Rothwell
2005-12-15 13:58 linux
2005-12-15 16:15 ` Linus Torvalds
2005-12-15 16:52 ` Erik Mouw
2005-12-15 17:23 ` Dick Streefland
2005-12-16 12:17 ` Erik Mouw
2005-12-17 10:59 ` Sander
2005-12-17 14:14 ` Douglas McNaught
2005-12-17 15:09 ` Sander
2005-12-19 10:44 ` Erik Mouw
2005-12-15 19:02 ` Nikita Danilov
2005-12-15 19:09 ` linux
2005-12-15 19:52 ` Linus Torvalds
2005-12-16 1:33 ` linux
2005-12-15 21:18 ` Steven Rostedt
2005-12-15 20:52 ` Steven Rostedt
2005-12-12 23:45 David Howells
2005-12-13 0:13 ` Nick Piggin
2005-12-13 0:19 ` Nick Piggin
2005-12-13 0:19 ` Andrew Morton
2005-12-13 7:54 ` Ingo Molnar
2005-12-13 7:58 ` Andi Kleen
2005-12-13 8:42 ` Andrew Morton
2005-12-13 8:49 ` Andi Kleen
2005-12-13 9:01 ` Andrew Morton
2005-12-13 9:02 ` Andrew Morton
2005-12-13 10:07 ` Jakub Jelinek
2005-12-13 10:11 ` Andi Kleen
2005-12-13 10:15 ` Jakub Jelinek
2005-12-13 10:25 ` Andrew Morton
2005-12-14 10:46 ` Russell King
2005-12-13 9:05 ` Andi Kleen
2005-12-13 9:15 ` Andrew Morton
2005-12-13 9:24 ` Andi Kleen
2005-12-13 9:44 ` Andrew Morton
2005-12-13 9:49 ` Andi Kleen
2005-12-13 10:28 ` Andreas Schwab
2005-12-13 10:30 ` Andi Kleen
2005-12-13 12:33 ` Matthew Wilcox
2005-12-13 22:18 ` Adrian Bunk
2005-12-13 22:25 ` Andi Kleen
2005-12-13 22:32 ` Adrian Bunk
2005-12-13 9:11 ` Ingo Molnar
2005-12-13 9:04 ` Christoph Hellwig
2005-12-13 9:13 ` Ingo Molnar
2005-12-13 10:11 ` Jakub Jelinek
2005-12-13 10:19 ` Christoph Hellwig
2005-12-13 10:27 ` Ingo Molnar
2005-12-15 4:53 ` Miles Bader
2005-12-15 5:05 ` Nick Piggin
2005-12-13 9:09 ` Ingo Molnar
2005-12-13 9:21 ` Andi Kleen
2005-12-13 16:16 ` Linus Torvalds
2005-12-13 9:03 ` Christoph Hellwig
2005-12-13 9:14 ` Andrew Morton
2005-12-13 9:21 ` Christoph Hellwig
2005-12-13 8:00 ` Arjan van de Ven
2005-12-13 9:03 ` Ingo Molnar
2005-12-13 9:09 ` Andi Kleen
2005-12-13 9:34 ` Ingo Molnar
2005-12-13 14:33 ` Mark Lord
2005-12-13 14:45 ` Arjan van de Ven
2005-12-13 9:37 ` Ingo Molnar
2005-12-13 9:19 ` Arjan van de Ven
2005-12-13 9:02 ` Christoph Hellwig
2005-12-13 9:39 ` Ingo Molnar
2005-12-13 10:00 ` Ingo Molnar
2005-12-13 17:40 ` Paul Jackson
2005-12-13 18:34 ` David Howells
2005-12-13 22:31 ` Paul Jackson
2005-12-14 11:02 ` David Howells
2005-12-14 11:12 ` David Howells
2005-12-14 11:18 ` Alan Cox
2005-12-14 12:35 ` David Howells
2005-12-14 13:58 ` Thomas Gleixner
2005-12-14 23:40 ` Mark Lord
2005-12-14 23:54 ` Andrew Morton
2005-12-15 13:41 ` Nikita Danilov
2005-12-15 14:56 ` Alan Cox
2005-12-15 15:52 ` Nikita Danilov
2005-12-15 16:50 ` Christopher Friesen
2005-12-15 20:53 ` Steven Rostedt
2005-12-15 15:55 ` David Howells
2005-12-15 16:22 ` linux-os (Dick Johnson)
2005-12-15 16:28 ` Linus Torvalds
2005-12-15 17:04 ` Thomas Gleixner
2005-12-15 17:09 ` Paul Jackson
2005-12-15 17:17 ` David Howells
2005-12-15 16:51 ` David Howells
2005-12-15 16:56 ` Paul Jackson
2005-12-15 17:28 ` David Howells
2005-12-15 17:48 ` Linus Torvalds
2005-12-15 18:20 ` Nikita Danilov
2005-12-15 20:58 ` Steven Rostedt
2005-12-15 19:21 ` Andrew Morton
2005-12-15 19:38 ` Linus Torvalds
2005-12-15 20:28 ` Steven Rostedt
2005-12-15 20:32 ` Geert Uytterhoeven
2005-12-16 21:41 ` Thomas Gleixner
2005-12-16 21:41 ` Linus Torvalds
2005-12-16 22:06 ` Thomas Gleixner
2005-12-16 22:19 ` Linus Torvalds
2005-12-16 22:32 ` Steven Rostedt
2005-12-16 22:42 ` Thomas Gleixner
2005-12-16 22:41 ` Linus Torvalds
2005-12-16 22:49 ` Steven Rostedt
2005-12-16 23:29 ` Thomas Gleixner
2005-12-17 0:29 ` Joe Korty
2005-12-17 1:00 ` Linus Torvalds
2005-12-17 3:13 ` Steven Rostedt
2005-12-17 7:34 ` Linus Torvalds
2005-12-17 23:43 ` Matthew Wilcox
2005-12-18 0:05 ` Lee Revell
2005-12-18 0:21 ` Matthew Wilcox
2005-12-18 1:25 ` Lee Revell
2005-12-22 12:27 ` Bill Huey
2005-12-19 16:08 ` Ingo Molnar
2005-12-22 12:40 ` Bill Huey
2005-12-22 12:45 ` Bill Huey
2005-12-19 23:46 ` Keith Owens
2005-12-15 14:41 ` Steven Rostedt
2005-12-14 23:57 ` Thomas Gleixner
2005-12-14 23:57 ` Mark Lord
2005-12-15 0:10 ` Thomas Gleixner
2005-12-15 2:46 ` Linus Torvalds
2005-12-15 15:53 ` David Howells
2005-12-15 15:37 ` David Howells
2005-12-15 19:28 ` Andrew Morton
2005-12-15 20:18 ` Andrew Morton
2005-12-15 21:28 ` Steven Rostedt
2005-12-16 22:02 ` Thomas Gleixner
2005-12-16 10:45 ` David Howells
2005-12-13 9:55 ` Ingo Molnar
2005-12-13 0:30 ` Arnd Bergmann
2005-12-13 0:57 ` Daniel Walker
2005-12-13 3:23 ` Steven Rostedt
2005-12-13 2:57 ` Mark Lord
2005-12-13 3:17 ` Steven Rostedt
2005-12-13 9:06 ` Christoph Hellwig
2005-12-13 9:54 ` David Howells
2005-12-13 10:13 ` Ingo Molnar
2005-12-13 10:34 ` Ingo Molnar
2005-12-13 10:37 ` Ingo Molnar
2005-12-13 12:47 ` Oliver Neukum
2005-12-13 13:09 ` Alan Cox
2005-12-13 13:13 ` Matthew Wilcox
2005-12-13 14:04 ` Alan Cox
2005-12-13 13:24 ` Oliver Neukum
2005-12-14 1:00 ` Nick Piggin
2005-12-14 10:54 ` David Howells
2005-12-14 11:17 ` Nick Piggin
2005-12-14 11:46 ` David Howells
2005-12-14 21:23 ` Nick Piggin
2005-12-16 12:00 ` David Howells
2005-12-16 13:16 ` Nick Piggin
2005-12-16 15:53 ` David Howells
2005-12-16 23:41 ` Nick Piggin
2005-12-16 16:02 ` David Howells
2005-12-13 10:48 ` David Howells
2005-12-13 12:39 ` Matthew Wilcox
2005-12-13 10:54 ` Ingo Molnar
2005-12-13 11:23 ` David Howells
2005-12-13 11:24 ` David Howells
2005-12-13 13:45 ` Ingo Molnar
2005-12-13 11:34 ` David Howells
2005-12-13 13:05 ` Alan Cox
2005-12-13 13:15 ` Alan Cox
2005-12-13 23:21 ` Nikita Danilov
2005-12-13 13:32 ` David Howells
2005-12-13 14:00 ` Alan Cox
2005-12-13 14:35 ` Christopher Friesen
2005-12-13 14:44 ` Arjan van de Ven
2005-12-13 14:59 ` Christopher Friesen
2005-12-13 15:23 ` David Howells
2005-12-15 5:24 ` Miles Bader
2005-12-13 15:39 ` David Howells
2005-12-13 16:10 ` Alan Cox
2005-12-14 10:29 ` Arjan van de Ven
2005-12-14 11:03 ` Arjan van de Ven
2005-12-14 11:03 ` Alan Cox
2005-12-14 11:08 ` Arjan van de Ven
2005-12-14 11:24 ` Alan Cox
2005-12-14 11:35 ` Andrew Morton
2005-12-14 11:44 ` Arjan van de Ven
2005-12-14 11:52 ` Andi Kleen
2005-12-14 11:55 ` Arjan van de Ven
2005-12-14 11:57 ` David Howells
2005-12-14 12:19 ` Jakub Jelinek
2005-12-16 1:54 ` Nick Piggin
2005-12-16 11:02 ` David Howells
2005-12-16 13:01 ` Nick Piggin
2005-12-16 13:21 ` Russell King
2005-12-16 13:41 ` Nick Piggin
2005-12-16 13:46 ` Linh Dang
2005-12-16 14:31 ` Russell King
2005-12-16 15:24 ` Linh Dang
2005-12-16 15:35 ` Nick Piggin
2005-12-16 15:40 ` Kyle Moffett
2005-12-16 15:49 ` Linh Dang
2005-12-16 15:46 ` David Howells
2005-12-16 15:58 ` Russell King
2005-12-17 15:57 ` Nikita Danilov
2005-12-16 16:28 ` Linus Torvalds
2005-12-16 11:30 ` David Howells
2005-12-16 16:33 ` Linus Torvalds
2005-12-16 22:23 ` David S. Miller
2005-12-16 22:38 ` Linus Torvalds
2005-12-16 22:53 ` David S. Miller
2005-12-17 0:41 ` Jesse Barnes
2005-12-17 7:10 ` David S. Miller
2005-12-17 7:40 ` Linus Torvalds
2005-12-17 17:22 ` Jesse Barnes
2005-12-17 17:19 ` Jesse Barnes
2005-12-17 22:38 ` Richard Henderson
2005-12-17 23:05 ` David S. Miller
2005-12-14 12:17 ` Christoph Hellwig
2005-12-14 11:42 ` Arjan van de Ven
2005-12-14 8:31 ` Ingo Molnar
2005-12-13 20:04 ` Steven Rostedt
2005-12-13 21:03 ` David Howells
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