From: Sanjay Patel <sanjay3000@yahoo•com>
To: benh@kernel•crashing.org
Cc: Mark Nelson <markn@au1•ibm.com>,
Gunnar von Boehn <VONBOEHN@de•ibm.com>,
Arnd Bergmann <arnd@arndb•de>,
linuxppc-dev@ozlabs•org, Michael Ellerman <ellerman@au1•ibm.com>,
cbe-oss-dev@ozlabs•org
Subject: Re: [RFC 1/3] powerpc: __copy_tofrom_user tweaked for Cell
Date: Fri, 20 Jun 2008 16:44:55 -0700 (PDT) [thread overview]
Message-ID: <834245.69039.qm@web33102.mail.mud.yahoo.com> (raw)
In-Reply-To: <1214004027.8011.182.camel@pasglop>
--- On Fri, 6/20/08, Benjamin Herrenschmidt <benh@kernel•crashing.org> wrote:
> I though OS X had a trick with a CR bit that would disable
> the dcbz optimization on the first alignment fault ? Or did they
> totally remove it ?
Ah, it's coming back to me. :)
Apple added 'dcbz', removed it, and then there was the clever trick of optimizing the code path with a boot-time perf test and/or changing the code on the first fault...I'm not sure what's implemented in the recent builds.
If Linux can do something similar, that should allow good perf on cacheable and cache-inhibited space as well as different CPUs (eg, if 'dcba' is available, then you don't need the alignment fault hack).
--Sanjay
next prev parent reply other threads:[~2008-06-20 23:44 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-19 7:53 [RFC 1/3] powerpc: __copy_tofrom_user tweaked for Cell Mark Nelson
2008-06-19 14:43 ` Arnd Bergmann
2008-06-19 15:17 ` Gunnar von Boehn
2008-06-19 16:13 ` Sanjay Patel
2008-06-20 11:36 ` Gunnar von Boehn
2008-06-20 17:46 ` Sanjay Patel
2008-06-20 23:20 ` Benjamin Herrenschmidt
2008-06-20 23:44 ` Sanjay Patel [this message]
2008-06-23 8:30 ` Gunnar von Boehn
2008-06-23 12:07 ` Geert Uytterhoeven
2008-06-23 23:49 ` Paul Mackerras
2008-06-27 13:30 ` Gunnar von Boehn
2008-06-20 1:13 ` [Cbe-oss-dev] " Paul Mackerras
2008-06-20 16:47 ` Gunnar von Boehn
2008-06-21 2:00 ` Arnd Bergmann
2008-06-21 4:30 ` Paul Mackerras
2008-06-21 4:49 ` David Miller
2008-06-21 21:06 ` Arnd Bergmann
2008-06-20 1:55 ` Mark Nelson
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