From: Andi Kleen <ak@suse.de>
To: "Bryan O'Sullivan" <bos@pathscale.com>
Subject: Re: [PATCH] Define flush_wc, a way to flush write combining store buffers
Date: Wed, 8 Mar 2006 15:21:18 +0100
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Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>, akpm@osdl.org,
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On Wednesday 08 March 2006 22:43, Bryan O'Sullivan wrote:
> On Thu, 2006-03-09 at 08:38 +1100, Benjamin Herrenschmidt wrote:
> 
> > I think people already don't undersatnd the existing gazillion of
> > barriers we have with quite unclear semantics in some cases, it's not
> > time to add a new one ...
> 
> What do you suggest I do, then?  This makes a substantial difference to
> performance for us.  Should I confine this somehow to the ipath driver
> directory and have a nest of ifdefs in an include file there?

I think doing it privately is the better solution because I don't think you 
have established it has an universal semantic that works
on all X86-64 systems.

And we don't have a portable way to do WC anyways, so there is 
no portable way to use it.

So just put an ifdef in.

-Andi
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