Re: NetBSD 5.1 TCP performance issue (lots of ACK)

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Sat, Oct 29, 2011 at 10:14:18PM +0200, Martin Husemann wrote:
> On Sat, Oct 29, 2011 at 10:02:10PM +0200, Manuel Bouyer wrote:
> > OK, I see. But, is there a platoform where BUS_DMASYNC_PREREAD is not
> > a NOP ? I can't what kind of work BUS_DMASYNC_PREREAD could have to do ...
> 
> On platforms with memory reordering it might be a barrier (i.e. sparc64 does
> a membar_sync() for it).

So does x86. But I think it's redundant with the POSTREAD (which is also
a barrier) we'll do later.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--