Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754003AbXFZAw4 (ORCPT ); Mon, 25 Jun 2007 20:52:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751677AbXFZAwt (ORCPT ); Mon, 25 Jun 2007 20:52:49 -0400 Received: from ms-smtp-01.nyroc.rr.com ([24.24.2.55]:46759 "EHLO ms-smtp-01.nyroc.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751001AbXFZAwt (ORCPT ); Mon, 25 Jun 2007 20:52:49 -0400 Subject: Re: [RFC PATCH 0/6] Convert all tasklets to workqueues From: Steven Rostedt To: Jonathan Corbet Cc: Ingo Molnar , LKML , Andrew Morton , Thomas Gleixner , Christoph Hellwig , john stultz , Oleg Nesterov , "Paul E. McKenney" , Dipankar Sarma , "David S. Miller" , matthew.wilcox@hp.com, kuznet@ms2.inr.ac.ru, Linus Torvalds In-Reply-To: <10203.1182816012@lwn.net> References: <10203.1182816012@lwn.net> Content-Type: text/plain Date: Mon, 25 Jun 2007 20:52:34 -0400 Message-Id: <1182819154.5493.234.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1349 Lines: 34 On Mon, 2007-06-25 at 18:00 -0600, Jonathan Corbet wrote: > A couple of days ago I said: > > > The cafe_ccic (OLPC) camera driver uses a tasklet to move frames out of > > the DMA buffers in the streaming I/O path.... > > > > Obviously some testing is called for here. I will make an attempt to do > > that testing > > I've done that testing - I have an OLPC B3 unit running V2 of the > tasklet->workqueue patch, and all seems well. 30 FPS to the display and > no dropped frames. The tasklets/0 process is running 3-5% CPU, in case > that's interesting. For whatever reason, I see about 3% *more* idle > time when running just mplayer than I did without the patch. > > Consider my minor qualms withdrawn, there doesn't seem to be any trouble > in this area. Jon, thanks a lot! This is great news. I wonder if converting tasklets to work queues also helps with other softirqs. Before, softirqs could not preempt a tasklet, since tasklets run as a softirq. With tasklets as work queues, what's left as a softirq can now preempt tasklets. Perhaps this can even help with performance. -- Steve - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/