netdev - Re: [PATCH net-next] net: skb_peek()/skb_peek

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Date:	Fri, 04 May 2012 15:01:31 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	David Miller <davem@...emloft.net>
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH net-next] net: skb_peek()/skb_peek_tail() cleanups

On Tue, 2012-05-01 at 09:41 -0400, David Miller wrote:
> From: Eric Dumazet <eric.dumazet@...il.com>
> Date: Tue, 01 May 2012 04:31:46 +0200
> 
> > From: Eric Dumazet <edumazet@...gle.com>
> > 
> > remove useless casts and rename variables for less confusion.
> > 
> > Signed-off-by: Eric Dumazet <edumazet@...gle.com>
> 
> Applied, I really need to get back to completing the list_head
> conversion :-/

Actually doubly linked lists everywhere has a performance issue.

When we dequeue one skb, we must bring in cpu cache the next skb as
well, to perform the unlink.

In some places it would be better to not have a double linked list, and
only perform a prefetch(skb->next).



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