From: Brian Gerst <bgerst@didntduck.org>
To: "Adam J. Richter" <adam@yggdrasil.com>
Cc: hpa@transmeta.com, linux-kernel@vger.kernel.org, ak@suse.de
Subject: Re: [Q] Looking for an emulation for CMOV* instructions.
Date: Sat, 12 Jan 2002 08:18:03 -0500 [thread overview]
Message-ID: <3C40378B.583AC9E3@didntduck.org> (raw)
In-Reply-To: <200201121048.CAA11276@adam.yggdrasil.com>
"Adam J. Richter" wrote:
>
> H. Peter Anvin wrote, in response to Andi Kleen:
> >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.
> [...]
>
> Your comment prompted me to look at
> linux-2.5.2-pre11/include/asm-i386/spinlock.h, and I now believe that
> the "lock; decb" that it uses for grabbing spinlocks will return an
> incorrect success if 255 or more processors are waiting on the same
> spinlock.
Implementation detail. You could just as easily use a long instead of a
char and have room for 2^32 processors.
--
Brian Gerst
next prev parent reply other threads:[~2002-01-12 13:17 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-12 10:48 [Q] Looking for an emulation for CMOV* instructions Adam J. Richter
2002-01-12 11:25 ` David Weinehall
2002-01-12 13:18 ` Brian Gerst [this message]
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
[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 ` Andi Kleen
2002-01-12 6:31 ` Pavel Machek
2002-01-12 7:52 ` H. Peter Anvin
-- 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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