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From: Chuck Ebbert <76306.1226@compuserve.com>
To: Kirill Korotaev <dev@sw.ru>
Cc: Andrew Morton <akpm@osdl.org>, Andrey Savochkin <saw@sawoct.com>,
	Linus Torvalds <torvalds@osdl.org>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: SMP syncronization on AMD processors (broken?)
Date: Sat, 8 Oct 2005 05:31:50 -0400	[thread overview]
Message-ID: <200510080534_MC3-1-AC2C-C212@compuserve.com> (raw)

In-Reply-To: <434520FF.8050100@sw.ru>

On Thu, 06 Oct 2005 at 17:05:03 +0400, Kirill Korotaev wrote:

> The question is whether concurrent spin_lock()'s should 
> acquire it in more or less "fair" fashinon or one of CPUs can starve any 
> arbitrary time while others do reacquire it in a loop.

 You neglected to say what CPU type you compiled the kernel for.

 If it wasn't Pentium Pro maybe you could patch include/asm-i386/spinlock.h
line 82 (or the same place in x86-64) like this:

___
  * (PPro errata 66, 92)
  */
 
-#if !defined(CONFIG_X86_OOSTORE) && !defined(CONFIG_X86_PPRO_FENCE)
+#if 0
 
 #define __raw_spin_unlock_string \
         "movb $1,%0" \
___

The data might not make it out of the CPU write buffer without a locking
instruction doing the update.
__
Chuck

             reply	other threads:[~2005-10-08  9:34 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-10-08  9:31 Chuck Ebbert [this message]
  -- strict thread matches above, loose matches on Subject: below --
2005-10-11 23:50 linux
2005-10-12  2:12 ` Christopher Friesen
2005-10-12  2:39   ` linux
2005-10-12  3:27     ` Kyle Moffett
2005-10-13 12:25 ` Kirill Korotaev
2005-10-06 13:05 Kirill Korotaev
2005-10-06 13:14 ` linux-os (Dick Johnson)
2005-10-06 13:19 ` Arjan van de Ven
2005-10-06 13:32   ` Andrey Savochkin
2005-10-06 14:22     ` Arjan van de Ven
2005-10-06 13:32 ` Andi Kleen
2005-10-06 13:46   ` Andrey Savochkin
2005-10-06 14:52     ` Linus Torvalds
2005-10-06 15:21       ` Andrey Savochkin
2005-10-06 15:46         ` Linus Torvalds
2005-10-11  0:59         ` Andrew Morton
2005-10-11  1:20           ` Andi Kleen
2005-10-11  3:20             ` Joe Seigh
2005-10-06 13:50   ` Eric Dumazet
2005-10-06 14:45 ` Linus Torvalds
2005-10-06 15:34   ` Hugh Dickins
2005-10-06 15:53     ` Eric Dumazet
2005-10-06 16:01     ` Linus Torvalds
2005-10-07 20:38 ` Joe Seigh
2005-10-07 20:57   ` Stephen Hemminger
2005-10-13 18:24 ` Joe Seigh

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