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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20090729123041.GA7440@gondor.apana.org.au>
Date:	Wed, 29 Jul 2009 20:30:41 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Jarek Poplawski <jarkao2@...il.com>
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 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.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
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