Re: [PATCH] Define wc_wmb, a write barrier for PCI write combining

From: Bryan O'Sullivan
Date: Tue Feb 28 2006 - 14:42:48 EST


On Tue, 2006-02-28 at 20:33 +0100, Andi Kleen wrote:

> Are you sure you used the right instruction? Normally CLFLUSH is used
> for such things, not a write barrier which really only changes ordering.

Hmm. It's possible we're just getting lucky because another write
happens somewhere else soon after the last write we perform as part of a
packet send. Perhaps, for complete correctness, we should be using
CLFLUSH instead of the last barrier. I'll have to look into this.

Thanks,

<b

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