netdev - Re: [0/14] GRO: Lots of microoptimisations

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: <20090616163856.GA17318@gondor.apana.org.au>
Date:	Wed, 17 Jun 2009 02:38:56 +1000
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Benjamin LaHaise <ben.lahaise@...erion.com>
Cc:	David Miller <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: [0/14] GRO: Lots of microoptimisations

On Tue, Jun 16, 2009 at 12:35:47PM -0400, Benjamin LaHaise wrote:
> On Fri, Jun 12, 2009 at 04:48:33PM -0700, David Miller wrote:
> > I find a 500Mbps difference, due to just one single cache miss on
> > every packet, simply astounding and unbelievable.  But hey, it is
> > what you are seeing, so something has to account for it. :)
> 
> The cache miss only accounts for ~50Mbpsi, it'd be nice if there was an 
> easy way to get the whole 500Mbps back.  The rest seems to be in the 
> general overhead of the GRO code vs the normal NAPI rx path.  The P4 
> Xeon is substantially worse at string operations than the Core 2 / Core i7 
> based Xeons, so I'm hoping to test and see if they do any better with the 
> GRO code when I get access to a new machine soon.

I'm hoping to get onto this tomorrow.  I think there's definitely
something broken because there's no way GRO should be slower than
GRO off.  Slightly slower than LRO perhaps but surely not worse than
not merging at all :)

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
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