Subject: Re: [PATCH] sky2: skb recycling

From: Stephen Hemminger <[email-masked]>
Date: Tue, 21 Oct 2008 13:38:11 -0700

On Tue, 21 Oct 2008 22:15:43 +0200
Eric Dumazet <[email-masked]> wrote:

> Rick Jones a écrit :
> > David Miller wrote:
> >> From: Stephen Hemminger <[email-masked]>
> >> Date: Mon, 20 Oct 2008 19:09:22 -0700
> >>
> >>
> >>> Add support for recycling tx buffers into receive buffers.
> >>> This is experimental at this point.
> >>>
> >>> Signed-off-by: Stephen Hemminger <[email-masked]>
> >>
> >>
> >> Experimental, but do you have any performance data at all?
> >> Just curious...
> > 
> > I've not had a good emily litella moment all day so I'll ask - is there 
> > really that much in the way of suitable skb's which are completely free 
> > after transmit completion?
> 
> Or, if we take another way, say a VOIP RTP machine sends and receive 20.000
>  packets per second, each being 200 bytes long, are transmited packets
> correctly sized at sendto() time to be candidates for recycling ?

No. Most locally generate packets aren't going to be right size because
they will be too small, cloned or fragmented.  It really only helps when forwarding.