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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Changli Gao <xiaosuo@gmail.com>
Cc: David Miller <davem@davemloft.net>,
	therbert@google.com, netdev@vger.kernel.org
Subject: Re: [PATCH v7] rps: Receive Packet Steering
Date: Wed, 17 Mar 2010 08:07:53 +0100	[thread overview]
Message-ID: <1268809673.2932.62.camel@edumazet-laptop> (raw)
In-Reply-To: <412e6f7f1003161854w32ed4516w2e52003097051fc7@mail.gmail.com>

Le mercredi 17 mars 2010 à 09:54 +0800, Changli Gao a écrit :
> On Wed, Mar 17, 2010 at 5:13 AM, David Miller <davem@davemloft.net> wrote:
> >
> > I'll integrate this as soon as I open up net-next-2.6
> 
> It is really a good news. Now linux also can dispatch packets as
> FreeBSD does via netisr. Can we walk farer, and support weighted
> distribution?
> 

May I ask why ? What would be the goal ?

If you perform too much work behalf the first cpu (the one actually
dealing with the device and dispatching packets to other cpus), you risk
bringing into its cache whole packet and consuming too many cpu cycles.

For instance, I would prefer a basic spreading, and try to reorganise
sk_buffs to that this cpu touches only one cache line in sk_buff, and
read one cache line in packet data to compute rxhash.

Then some NIC could compute rxhash themselves and provide it in their
rx_desc. Of course multiqueue support is much better and current
hardware prefer to implement the real thing.




  reply	other threads:[~2010-03-17  7:07 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-12 20:13 [PATCH v7] rps: Receive Packet Steering Tom Herbert
2010-03-12 21:28 ` Eric Dumazet
2010-03-12 23:08   ` Tom Herbert
2010-03-16 18:03     ` Tom Herbert
2010-03-16 21:00       ` Eric Dumazet
2010-03-16 21:13         ` David Miller
2010-03-17  1:54           ` Changli Gao
2010-03-17  7:07             ` Eric Dumazet [this message]
2010-03-17  7:59               ` Changli Gao
2010-03-17 14:09                 ` Eric Dumazet
2010-03-17 15:01                   ` Tom Herbert
2010-03-17 15:34                     ` Eric Dumazet
2010-03-17 23:50                     ` Tom Herbert
2010-03-18  2:14                       ` Changli Gao
2010-03-18  6:30                         ` Eric Dumazet
2010-03-18  6:20                       ` Eric Dumazet
2010-03-18  6:48                         ` Changli Gao
2010-03-18 20:37                           ` Eric Dumazet
2010-03-18 21:23                             ` Stephen Hemminger
2010-03-17  4:26         ` David Miller
2010-03-12 22:20 ` Stephen Hemminger
2010-03-12 22:32   ` David Miller
2010-03-12 22:23 ` Stephen Hemminger
2010-03-12 22:33   ` David Miller
2010-03-12 23:05   ` Tom Herbert

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