Re: [PATCH net-next] bnx2x: dont use netdev_alloc_skb()

Eric Dumazet
2010-10-12T05:16:22Z

Le lundi 11 octobre 2010 à 22:03 -0700, Tom Herbert a écrit :
> On Mon, Oct 11, 2010 at 4:22 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> > Le mardi 12 octobre 2010 à 01:03 +0200, Eric Dumazet a écrit :
> >> netdev_alloc_skb() is a very wrong interface, really.
> >>
> >> We should remove/deprecate it.
> >>
> >> For multi queue devices, it makes more sense to allocate skb on local
> >> node of the cpu handling RX interrupts. This allow each cpu to
> >> manipulate its own slub/slab queues/structures without doing expensive
> >> cross-node business.
> >>
> >> For non multi queue devices, IRQ affinity should be set so that a cpu
> >> close to the device services interrupts. Even if not set, using
> >> dev_alloc_skb() is faster.
> >>
> >> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> >
> > Or maybe revert :
> >
> > commit b30973f877fea1a3fb84e05599890fcc082a88e5
> > Author: Christoph Hellwig <hch@lst.de>
> > Date: Wed Dec 6 20:32:36 2006 -0800
> >
>
> I second this revert. Node aware allocation by device's node makes
> little sense on a multi-queue device and leads to mediocre
> performance.

Yes, I said this several time in the past, I believe time has come to
get rid of it.

I posted a patch some minutes ago, so you can review it and ack it ;)

Thanks !