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From: Jamal Hadi Salim <jhs@mojatatu.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>,
	Willem de Bruijn <willemb@google.com>,
	netdev@vger.kernel.org, davem@davemloft.net
Subject: Re: [PATCH net-next v4] rps: selective flow shedding during softnet overflow
Date: Tue, 23 Apr 2013 21:25:54 -0400	[thread overview]
Message-ID: <517734A2.9060609@mojatatu.com> (raw)
In-Reply-To: <1366762196.8964.46.camel@edumazet-glaptop>

On 13-04-23 08:09 PM, Eric Dumazet wrote:

> qdisc code has a hardcoded dev_hard_start_xmit() call, thats why ifb
> hack is used. Not mentioning device flow control.
>
> It might be possible to use a q->xmit() method instead, so that it can
> be used on ingress without ifb.
>

If i understood correctly what you are trying to achieve:
I dont think one qdisc per rx queue/ring will work well in
presence of qdisc since the qdisc is attached per netdev.
i.e when packets are fanned out across cpu backlogs, as long
as they came in via same netdev queue, they are going to share
the same lock with all other cpus such packets have been fanned out to
the moment you attach an ingress qdisc to that netdev ring/queue.

One unorthodox approach is to have a qdisc per backlog queue
since the backlog is per cpu; given it is abstracted as a netdev,
it becomes a natural fit (sans the fact backlog queue is
unidirectional).

cheers,
jamal

  parent reply	other threads:[~2013-04-24  1:26 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-19 17:46 [PATCH] rps: selective flow shedding during softnet overflow Willem de Bruijn
2013-04-19 17:58 ` Eric Dumazet
2013-04-22 20:40   ` Willem de Bruijn
2013-04-22 20:46     ` [PATCH net-next v2] " Willem de Bruijn
2013-04-22 22:30       ` Eric Dumazet
2013-04-23 18:45         ` Willem de Bruijn
2013-04-23 18:46           ` [PATCH net-next v3] " Willem de Bruijn
2013-04-23 19:18             ` Eric Dumazet
2013-04-23 20:30               ` Willem de Bruijn
2013-04-23 20:31                 ` [PATCH net-next v4] " Willem de Bruijn
2013-04-23 21:23                   ` Stephen Hemminger
2013-04-23 21:37                     ` Willem de Bruijn
2013-04-23 21:37                     ` Eric Dumazet
2013-04-23 21:52                       ` Stephen Hemminger
2013-04-23 22:34                         ` David Miller
2013-04-24  0:09                         ` Eric Dumazet
2013-04-24  0:37                           ` [PATCH net-next v5] " Willem de Bruijn
2013-04-24  1:07                             ` Eric Dumazet
2013-04-25  8:20                             ` David Miller
2013-05-20 14:02                               ` [PATCH net-next v6] " Willem de Bruijn
2013-05-20 16:00                                 ` Eric Dumazet
2013-05-20 16:08                                   ` Willem de Bruijn
2013-05-20 20:48                                   ` David Miller
2013-04-24  1:25                           ` Jamal Hadi Salim [this message]
2013-04-24  1:32                             ` [PATCH net-next v4] " Eric Dumazet
2013-04-24  1:44                               ` Jamal Hadi Salim
2013-04-24  2:11                                 ` Eric Dumazet
2013-04-24 13:00                                   ` Jamal Hadi Salim
2013-04-24 14:41                                     ` Eric Dumazet
2013-04-23 22:33                     ` David Miller
2013-04-23 21:34                   ` Eric Dumazet
2013-04-23 22:41                   ` David Miller
2013-04-23 23:11                     ` Eric Dumazet
2013-04-23 23:15                       ` David Miller
2013-04-23 23:26                         ` Eric Dumazet
2013-04-24  0:03                         ` Stephen Hemminger
2013-04-24  0:00                     ` Willem de Bruijn
2013-04-23 20:46                 ` [PATCH net-next v3] " Eric Dumazet
2013-04-19 19:03 ` [PATCH] " Stephen Hemminger
2013-04-19 19:21   ` Eric Dumazet
2013-04-19 20:11   ` Willem de Bruijn

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