From: Andi Kleen <andi@firstfloor.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Patrick McHardy <kaber@trash.net>,
Herbert Xu <herbert@gondor.apana.org.au>,
"H.K. Jerry Chu" <hkchu@google.com>,
Michael Dalton <mwdalton@google.com>,
netdev <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] csum experts, csum_replace2() is too expensive
Date: Fri, 21 Mar 2014 14:28:20 +0100 [thread overview]
Message-ID: <20140321132820.GM22728@two.firstfloor.org> (raw)
In-Reply-To: <1395406250.9114.142.camel@edumazet-glaptop2.roam.corp.google.com>
On Fri, Mar 21, 2014 at 05:50:50AM -0700, Eric Dumazet wrote:
> On Thu, 2014-03-20 at 18:56 -0700, Andi Kleen wrote:
> > Eric Dumazet <eric.dumazet@gmail.com> writes:
> > >
> > > I saw csum_partial() consuming 1% of cpu cycles in a GRO workload, that
> > > is insane...
> >
> >
> > Couldn't it just be the cache miss?
>
> Or the fact that we mix 16 bit stores and 32bit loads ?
It should cause a small stall from not doing load-store
forwarding, but 1% of a serious workload would be surprising.
Are you sure it's not some skid effect?
-Andi
next prev parent reply other threads:[~2014-03-21 13:28 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-20 18:49 [RFC] csum experts, csum_replace2() is too expensive Eric Dumazet
2014-03-21 0:13 ` Herbert Xu
2014-03-21 0:54 ` Eric Dumazet
2014-03-21 12:50 ` Herbert Xu
2014-03-21 1:56 ` Andi Kleen
2014-03-21 2:51 ` Eric Dumazet
2014-03-21 12:50 ` Eric Dumazet
2014-03-21 13:28 ` Andi Kleen [this message]
2014-03-21 13:32 ` Eric Dumazet
2014-03-21 13:47 ` Eric Dumazet
2014-03-21 13:56 ` Eric Dumazet
2014-03-21 14:14 ` David Laight
2014-03-21 14:14 ` David Laight
2014-03-21 18:52 ` David Miller
2014-03-24 2:50 ` Eric Dumazet
2014-03-24 10:30 ` David Laight
2014-03-24 10:30 ` David Laight
2014-03-24 13:17 ` Eric Dumazet
2014-03-24 14:13 ` Eric Dumazet
2014-03-21 18:07 ` David Miller
2014-03-21 18:30 ` Eric Dumazet
2014-03-24 2:51 ` [PATCH net-next] net: optimize csum_replace2() Eric Dumazet
2014-03-24 4:20 ` David Miller
2014-03-24 10:22 ` David Laight
2014-03-24 13:25 ` Eric Dumazet
2014-03-24 14:38 ` David Laight
2014-03-24 15:14 ` Eric Dumazet
2014-03-24 15:52 ` David Laight
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