From: David Miller <davem@davemloft.net>
To: herbert@gondor.apana.org.au
Cc: billfink@mindspring.com, ilpo.jarvinen@helsinki.fi,
netdev@vger.kernel.org, jheffner@psc.edu
Subject: Re: TSO trimming question
Date: Fri, 21 Dec 2007 01:36:42 -0800 (PST) [thread overview]
Message-ID: <20071221.013642.29817274.davem@davemloft.net> (raw)
In-Reply-To: <20071221092927.GA32434@gondor.apana.org.au>
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Fri, 21 Dec 2007 17:29:27 +0800
> On Fri, Dec 21, 2007 at 01:27:20AM -0800, David Miller wrote:
> >
> > It's two shifts, and this gets scheduled along with the other
> > instructions on many cpus so it's effectively free.
> >
> > I don't see why this is even worth mentioning and discussing.
>
> I totally agree. Two shifts are way better than a branch.
We take probably a thousand+ 100+ cycle cache misses in the TCP stack
on big window openning ACKs.
Instead of discussing ways to solve that huge performance killer we're
wanking about two friggin' integer shifts.
It's hilarious isn't it? :-)
next prev parent reply other threads:[~2007-12-21 9:36 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-19 21:46 TSO trimming question Ilpo Järvinen
2007-12-19 22:02 ` Ilpo Järvinen
2007-12-20 3:26 ` Herbert Xu
2007-12-20 7:55 ` David Miller
2007-12-20 7:54 ` David Miller
2007-12-20 11:40 ` Ilpo Järvinen
2007-12-20 11:56 ` David Miller
2007-12-20 16:02 ` John Heffner
2007-12-21 4:36 ` David Miller
2007-12-21 8:06 ` Bill Fink
2007-12-21 9:26 ` Ilpo Järvinen
2007-12-21 9:28 ` Ilpo Järvinen
2007-12-21 9:27 ` David Miller
2007-12-21 9:29 ` Herbert Xu
2007-12-21 9:36 ` David Miller [this message]
2007-12-21 10:58 ` Bill Fink
2007-12-21 18:54 ` Bill Fink
2007-12-21 18:58 ` Ilpo Järvinen
2007-12-21 19:37 ` Bill Fink
2007-12-20 12:00 ` David Miller
2007-12-20 12:35 ` Ilpo Järvinen
2007-12-20 14:00 ` Herbert Xu
2007-12-20 23:55 ` David Miller
2007-12-21 18:55 ` [PATCH] [TCP]: Force TSO splits to MSS boundaries Ilpo Järvinen
2007-12-21 20:01 ` Ilpo Järvinen
2007-12-25 5:35 ` David Miller
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