From: Jarek Poplawski <jarkao2@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: dada1@cosmosbay.com, vernux@us.ibm.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org
Subject: Re: High contention on the sk_buff_head.lock
Date: Mon, 23 Mar 2009 08:50:58 +0000 [thread overview]
Message-ID: <20090323085058.GC4976@ff.dom.local> (raw)
In-Reply-To: <20090323.013749.122944803.davem@davemloft.net>
On Mon, Mar 23, 2009 at 01:37:49AM -0700, David Miller wrote:
> From: Eric Dumazet <dada1@cosmosbay.com>
> Date: Mon, 23 Mar 2009 09:32:39 +0100
>
> > I dont understand, doesnt it defeat the ticket spinlock thing and fairness ?
> >
> > Thread doing __qdisc_run() already owns the __QDISC_STATE_RUNNING bit.
>
> Right.
>
> Remember, the way this is designed is that if there is a busy
> cpu taking packets out of the queue and putting them into the
> device then other cpus will simply add to the queue and immediately
> return.
But this "busy cpu" can't take packets out of the queue when it's
waiting on the contended spinlock. Anyway, it's only for testing,
and I didn't say it has to be right.
Jarek P.
next prev parent reply other threads:[~2009-03-23 8:50 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-18 17:24 High contention on the sk_buff_head.lock Vernon Mauery
2009-03-18 19:07 ` Eric Dumazet
2009-03-18 20:17 ` Vernon Mauery
2009-03-20 23:29 ` Jarek Poplawski
2009-03-23 8:32 ` Eric Dumazet
2009-03-23 8:32 ` Eric Dumazet
2009-03-23 8:37 ` David Miller
2009-03-23 8:50 ` Jarek Poplawski [this message]
2009-04-02 14:13 ` Herbert Xu
2009-04-02 14:15 ` Herbert Xu
2009-03-18 20:54 ` Andi Kleen
2009-03-18 21:03 ` David Miller
2009-03-18 21:10 ` Vernon Mauery
2009-03-18 21:38 ` David Miller
2009-03-18 21:49 ` Vernon Mauery
2009-03-19 1:02 ` David Miller
2009-03-18 21:54 ` Gregory Haskins
2009-03-19 1:03 ` David Miller
2009-03-19 1:13 ` Sven-Thorsten Dietrich
2009-03-19 1:17 ` David Miller
2009-03-19 1:43 ` Sven-Thorsten Dietrich
2009-03-19 1:54 ` David Miller
2009-03-19 5:49 ` Eric Dumazet
2009-03-19 5:49 ` Eric Dumazet
2009-03-19 5:58 ` David Miller
2009-03-19 14:04 ` [PATCH] net: reorder struct Qdisc for better SMP performance Eric Dumazet
2009-03-19 14:04 ` Eric Dumazet
2009-03-20 8:33 ` David Miller
2009-03-19 13:45 ` High contention on the sk_buff_head.lock Andi Kleen
2009-03-19 3:48 ` Gregory Haskins
2009-03-19 5:38 ` David Miller
2009-03-19 12:42 ` Gregory Haskins
2009-03-19 20:52 ` David Miller
2009-03-19 12:50 ` Peter W. Morreale
2009-03-19 7:15 ` Evgeniy Polyakov
2009-03-18 21:07 ` Vernon Mauery
2009-03-18 21:45 ` Eilon Greenstein
2009-03-18 21:51 ` Vernon Mauery
2009-03-18 21:59 ` Andi Kleen
2009-03-18 22:19 ` Rick Jones
2009-03-19 12:59 ` Peter W. Morreale
2009-03-19 13:36 ` Peter W. Morreale
2009-03-19 13:46 ` Andi Kleen
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