Re: [rfc][patch 2/3] x86: fix IO write barriers

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From: Dave Jones
Date: Thursday, October 4, 2007 - 11:10 am

On Thu, Oct 04, 2007 at 07:53:16PM +0200, Andi Kleen wrote:
 > 
 > > The only vendor that ever implemented OOSTOREs was Centaur, and they
 > > only did in the Winchip generation of the CPUs.  When they dropped it
 > > from the C3, I asked whether they intended to bring it back, and the
 > > answer was "extremely unlikely".
 > >
 > 
 > Do you know if it made a big performance difference?

On the winchip, it was a huge win. I can't remember exact numbers,
but pretty much every benchmark I threw at it at the time showed
significant improvement.

 > But yes we should probably just remove this special case to make 
 > maintenance easier.

It's CONFIG_SMP anyway, which none of the winchips were.
SMP+OOSTORE just didn't happen, and I'd be surprised if
any vendor makes it happen any time soon.
(Even if so, it's likely we'd need to make additional changes
 anyway, so adding it back shouldn't be a big deal.)

	Dave

-- 
http://www.codemonkey.org.uk
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Messages in current thread:
[rfc][patch 1/3] x86_64: fence nontemproal stores, Nick Piggin, (Wed Oct 3, 10:21 pm)
[rfc][patch 2/3] x86: fix IO write barriers, Nick Piggin, (Wed Oct 3, 10:22 pm)
[rfc][patch 3/3] x86: optimise barriers, Nick Piggin, (Wed Oct 3, 10:23 pm)
Re: [rfc][patch 2/3] x86: fix IO write barriers, Dave Jones, (Thu Oct 4, 10:32 am)
Re: [rfc][patch 2/3] x86: fix IO write barriers, Andi Kleen, (Thu Oct 4, 10:53 am)
Re: [rfc][patch 2/3] x86: fix IO write barriers, Dave Jones, (Thu Oct 4, 11:10 am)
Re: [rfc][patch 2/3] x86: fix IO write barriers, Andi Kleen, (Thu Oct 4, 11:21 am)
Re: [rfc][patch 2/3] x86: fix IO write barriers, Dave Jones, (Thu Oct 4, 11:41 am)
Re: [rfc][patch 2/3] x86: fix IO write barriers, Andi Kleen, (Thu Oct 4, 11:58 am)
Re: [rfc][patch 2/3] x86: fix IO write barriers, Dave Jones, (Thu Oct 4, 12:08 pm)
Re: [rfc][patch 2/3] x86: fix IO write barriers, Alan Cox, (Thu Oct 4, 1:52 pm)
Re: [rfc][patch 3/3] x86: optimise barriers, Jarek Poplawski, (Fri Oct 12, 1:25 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Helge Hafting, (Fri Oct 12, 1:42 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Nick Piggin, (Fri Oct 12, 1:57 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Jarek Poplawski, (Fri Oct 12, 2:12 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Nick Piggin, (Fri Oct 12, 2:44 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Jarek Poplawski, (Fri Oct 12, 2:55 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Jarek Poplawski, (Fri Oct 12, 3:04 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Nick Piggin, (Fri Oct 12, 3:42 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Jarek Poplawski, (Fri Oct 12, 4:55 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Jarek Poplawski, (Fri Oct 12, 5:10 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Helge Hafting, (Fri Oct 12, 5:44 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Jarek Poplawski, (Fri Oct 12, 6:29 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Linus Torvalds, (Fri Oct 12, 8:13 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Jarek Poplawski, (Mon Oct 15, 12:44 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Nick Piggin, (Mon Oct 15, 1:09 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Jarek Poplawski, (Mon Oct 15, 2:10 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Jarek Poplawski, (Mon Oct 15, 2:24 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Helge Hafting, (Mon Oct 15, 3:17 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Jarek Poplawski, (Mon Oct 15, 4:53 am)
RE: [rfc][patch 3/3] x86: optimise barriers, David Schwartz, (Mon Oct 15, 7:38 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Nick Piggin, (Mon Oct 15, 5:50 pm)
Re: [rfc][patch 3/3] x86: optimise barriers, Jarek Poplawski, (Tue Oct 16, 2:00 am)
Re: [rfc][patch 3/3] x86: optimise barriers, david, (Tue Oct 16, 2:14 am)
Re: [rfc][patch 3/3] x86: optimise barriers, Jarek Poplawski, (Tue Oct 16, 5:49 am)