Re: [PATCH] x86: Run checksumming in parallel accross multiplealu's

From: SÃbastien DuguÃ
Date: Tue Oct 15 2013 - 10:15:36 EST


Hi Eric,

On Tue, 15 Oct 2013 07:06:25 -0700
Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote:

> On Tue, 2013-10-15 at 15:56 +0200, SÃbastien Duguà wrote:
> > On Tue, 15 Oct 2013 15:33:36 +0200
> > Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
> >
> > > > indeed, our typical workload is connected mode IPoIB on mlx4 QDR hardware
> > > > where one cannot benefit from hardware offloads.
> > >
> > > Is this with sendfile?
> >
> > Tests were done with iperf at the time without any extra funky options, and
> > looking at the code it looks like it does plain write() / recv() on the socket.
> >
>
> But the csum cost is both for sender and receiver ?

No, it was only on the receiver side that I noticed it.

>
> Please post the following :
>
> perf record -g "your iperf session"
>
> perf report | head -n 200

Sorry, but this is 3 years old stuff and I do not have the
setup anymore to reproduce.

SÃbastien.


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