From: "Joakim Tjernlund" <Joakim.Tjernlund@lumentis.se>
To: "Jeff Garzik" <jgarzik@pobox.com>
Cc: <linux-kernel@vger.kernel.org>
Subject: Re: NETIF_F_SG question
Date: Sat, 1 Feb 2003 19:42:01 +0100 [thread overview]
Message-ID: <005701c2ca21$9c1d90b0$020120b0@jockeXP> (raw)
In-Reply-To: 3E3C0684.4010806@pobox.com
> Joakim Tjernlund wrote:
> > I am thinking of implementing harware scatter/gatter support( NETIF_F_SG) in my
> > ethernet driver. The network device cannot do HW checksuming.
> >
> > Will the IP stack make use of the SG support and will there be any significant performance
> > improvement?
>
>
> No; you need HW checksumming for NETIF_F_SG to be useful.
>
> If HW checksumming is not available, scatter-gather is useless, because
> the net stack must always make a pass over the data to checksum it.
> Since it must do that, it can linearize the skb at the same time,
> eliminating the need for SG.
>
> Jeff
linearize = copy small buffers inte one big buffer, or?
Surley the copy operation will cost something?
Jocke
next prev parent reply other threads:[~2003-02-01 18:32 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-02-01 15:08 NETIF_F_SG question Joakim Tjernlund
2003-02-01 17:40 ` Jeff Garzik
2003-02-01 18:42 ` Joakim Tjernlund [this message]
2003-02-01 19:16 ` romieu
2003-02-01 22:16 ` Joakim Tjernlund
2003-02-02 1:39 ` Joakim Tjernlund
2003-02-03 21:18 ` Ion Badulescu
2003-02-03 22:22 ` Joakim Tjernlund
2003-02-03 22:34 ` Ion Badulescu
2003-02-03 22:44 ` Joakim Tjernlund
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