lkml.org 
[lkml]   [2009]   [Mar]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: High contention on the sk_buff_head.lock
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.


\
 
 \ /
  Last update: 2009-03-23 09:55    [W:0.084 / U:0.160 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site