From: Eric Dumazet <eric.dumazet@gmail.com>
To: Changli Gao <xiaosuo@gmail.com>
Cc: hadi@cyberus.ca, "David S. Miller" <davem@davemloft.net>,
Stephen Hemminger <shemminger@linux-foundation.org>,
Tom Herbert <therbert@google.com>, Jiri Pirko <jpirko@redhat.com>,
netdev@vger.kernel.org, netem@lists.linux-foundation.org
Subject: Re: [PATCH 5/5 v4] net: add old_queue_mapping into skb->cb
Date: Tue, 21 Dec 2010 16:24:35 +0100 [thread overview]
Message-ID: <1292945075.2720.32.camel@edumazet-laptop> (raw)
In-Reply-To: <AANLkTimqemuhxCKq-PJu+FD-MDgKaHnYKnP_2ch30wxE@mail.gmail.com>
Le mardi 21 décembre 2010 à 22:03 +0800, Changli Gao a écrit :
> However, I don't think change the rx queue mapping is a good idea.
> When the skbs returned from ifb enter netif_receive_skb() again,
> get_rps_cpu() may warn about the wrong rx queue, and my this patch is
> used to solve this problem. Even though the rx queue is legal, a
> different rps_cpus settings will be used, and the skbs may be
> redirected to different CPUs. Is it expected?
>
>
Do we really want a multi queue ifb at all ?
Why not use percpu data and LLTX, like we did for other virtual devices
(loopback, tunnels, vlans, ...)
I guess most ifb uses need to finaly deliver packets in a monoqueue
anyway, optimizing ifb might raise lock contention on this resource.
See what we did in commit 79640a4ca6955e3e (net: add additional lock to
qdisc to increase throughput) : Adding one spinlock actually helped a
lot ;)
next prev parent reply other threads:[~2010-12-21 15:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-16 4:56 [PATCH 5/5 v4] net: add old_queue_mapping into skb->cb Changli Gao
2010-12-16 5:47 ` Eric Dumazet
2010-12-17 13:09 ` jamal
2010-12-17 13:41 ` Changli Gao
2010-12-21 13:07 ` jamal
2010-12-21 14:03 ` Changli Gao
2010-12-21 15:24 ` Eric Dumazet [this message]
2010-12-22 0:08 ` Changli Gao
2010-12-23 13:21 ` jamal
2010-12-23 13:00 ` jamal
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