netdev - Re: [RFC] [PATCH] Don't run __qdisc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20090729124734.GD5490@ff.dom.local>
Date:	Wed, 29 Jul 2009 12:47:34 +0000
From:	Jarek Poplawski <jarkao2@...il.com>
To:	Herbert Xu <herbert@...dor.apana.org.au>
Cc:	David Miller <davem@...emloft.net>, krkumar2@...ibm.com,
	netdev@...r.kernel.org
Subject: Re: [RFC] [PATCH] Don't run __qdisc_run() on a stopped TX queue

On Wed, Jul 29, 2009 at 08:30:41PM +0800, Herbert Xu wrote:
> On Wed, Jul 29, 2009 at 11:26:14AM +0000, Jarek Poplawski wrote:
> >
> > If you mean the tx lock there should be no "real" contention: only
> > one waiter max. qdisc lock's contention might be higher, but it's
> > use (during contention) better: enqueue + dequeue together instead
> > of doing it separately.
> 
> Hmm, you will have contention if they're both transmitting a
> single flow which must always go into a single physical queue.
> 
> So you'll have two CPUs doing the work of a single CPU, with one
> of them always spinning on the TX lock.

Hmm.. I'd call it a little waiting, but OK let's call it contention;-)
When tx is faster than queue operations there could be no contention
at all. I'm not saying I must be right: IMHO it's only worth trying.

Cheers,
Jarek P.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html