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Subject: Re: AltiVec in the kernel
From: Johannes Berg <johannes@sipsolutions.net>
To: Paul Mackerras <paulus@samba.org>
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Date: Wed, 19 Jul 2006 20:38:21 +0200
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On Thu, 2006-07-20 at 04:19 +1000, Paul Mackerras wrote:
> Linas Vepstas writes:
>=20
> > But perhaps, in principle, couldn't one run four independent streams=20
> > in parallel?  Thus, for example, on an SSL-enabled web server, one=20
> > could service multiple encryption/decryption threads at once.=20
>=20
> Generally that would work.  If one had 4 separate streams to compute a
> SHA1 of, one could do all 4 at once with altivec.  It would have to be
> 4 separate streams though, not 4 parts of a single stream.

I'd think it'd be pretty hard to get a real benefit from this because
the data is going to come from 4 totally different places, hence you
can't just load a single vector register and get data for all 4
streams...

johannes

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