netdev - Re: [RFC] csum experts, csum_replace2() is too expensive

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1395370311.9114.121.camel@edumazet-glaptop2.roam.corp.google.com>
Date:	Thu, 20 Mar 2014 19:51:51 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	Patrick McHardy <kaber@...sh.net>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	"H.K. Jerry Chu" <hkchu@...gle.com>,
	Michael Dalton <mwdalton@...gle.com>,
	netdev <netdev@...r.kernel.org>
Subject: Re: [RFC] csum experts, csum_replace2() is too expensive

On Thu, 2014-03-20 at 18:56 -0700, Andi Kleen wrote:
> Eric Dumazet <eric.dumazet@...il.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?

Well, no, because we aggregate frames that were already fully checked
(by GRO engine/layers) in the same NAPI run.

In this particular case, it seems we aggregate few frames per run (its a
40Gb Intel NIC, it apparently is tuned for low latency)



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html