From: "H. Peter Anvin" <hpa@zytor.com>
To: linux-kernel@vger.kernel.org
Subject: Re: [Q] Looking for an emulation for CMOV* instructions.
Date: 11 Jan 2002 23:52:50 -0800 [thread overview]
Message-ID: <a1oq0i$ino$1@cesium.transmeta.com> (raw)
In-Reply-To: <m26669olcu.fsf@goliath.csn.tu-chemnitz.de.suse.lists.linux.kernel> <E16Oocq-0005tX-00@the-village.bc.nu.suse.lists.linux.kernel> <p737kqpp60w.fsf@oldwotan.suse.de>
Followup to: <p737kqpp60w.fsf@oldwotan.suse.de>
By author: Andi Kleen <ak@suse.de>
In newsgroup: linux.dev.kernel
>
> One corner case where emulation would IMHO make sense would be CMPXCHG8.
> It would allow to do efficient inline mutexes in pthreads, and hit the
> emulation only on 386/486. cpu feature flag checking is unfortunately
> not an option normally for inline code.
>
You don't need CMPXCHG8B to do efficient inline mutexes. In fact, the
pthreads code for i386 uses the same mutexes the kernel does (LOCK INC
based, I believe), complete with section hacking to make them
efficiently inlinable -- and then they're put inside a function call.
I believe "kill me now" is an appropriate response.
-hpa
--
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
http://www.zytor.com/~hpa/puzzle.txt <amsp@zytor.com>
next prev parent reply other threads:[~2002-01-12 7:53 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <m26669olcu.fsf@goliath.csn.tu-chemnitz.de.suse.lists.linux.kernel>
[not found] ` <E16Oocq-0005tX-00@the-village.bc.nu.suse.lists.linux.kernel>
2002-01-11 9:54 ` [Q] Looking for an emulation for CMOV* instructions Andi Kleen
2002-01-12 6:31 ` Pavel Machek
2002-01-12 7:52 ` H. Peter Anvin [this message]
2002-01-12 10:48 Adam J. Richter
2002-01-12 11:25 ` David Weinehall
2002-01-12 13:18 ` Brian Gerst
2002-01-12 20:43 ` H. Peter Anvin
[not found] <200201111845.g0BIjS2318104@saturn.cs.uml.edu>
2002-01-12 9:00 ` willy tarreau
2002-01-12 18:57 ` Alan Cox
-- strict thread matches above, loose matches on Subject: below --
2002-01-11 9:25 willy tarreau
2002-01-11 17:55 ` Ronald Wahl
[not found] <fa.eln67tv.a4io16@ifi.uio.no>
[not found] ` <fa.gp0gofv.1p4se16@ifi.uio.no>
2002-01-11 8:12 ` Giacomo Catenazzi
2002-01-10 23:08 Ronald Wahl
2002-01-10 23:28 ` Alan Cox
2002-01-11 0:08 ` Ronald Wahl
2002-01-11 0:26 ` Alan Cox
2002-01-11 0:39 ` Ronald Wahl
2002-01-11 0:54 ` Alan Cox
2002-01-11 1:09 ` Martin Eriksson
2002-01-11 1:42 ` Timothy Covell
2002-01-11 2:16 ` Alan Cox
2002-01-11 18:24 ` Ronald Wahl
2002-01-11 22:18 ` Richard Henderson
2002-01-11 23:07 ` Alan Cox
2002-01-11 23:26 ` Albert D. Cahalan
2002-01-11 23:40 ` Alan Cox
2002-01-16 15:18 ` Jamie Lokier
2002-01-16 16:16 ` Richard B. Johnson
2002-01-16 17:48 ` Ronald Wahl
2002-01-16 17:30 ` Dave Jones
2002-01-17 11:54 ` Maciej W. Rozycki
2002-01-11 19:59 ` Hans-Peter Jansen
2002-01-11 20:05 ` Ronald Wahl
2002-01-11 23:19 ` Alan Cox
2002-01-12 6:27 ` Pavel Machek
2002-04-12 20:48 ` H. Peter Anvin
2002-01-12 6:34 ` Pavel Machek
2002-01-18 17:38 ` David Woodhouse
2002-01-18 22:01 ` Pavel Machek
2002-01-11 23:25 ` Alistair Riddell
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