From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756059AbYICXu0 (ORCPT ); Wed, 3 Sep 2008 19:50:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752862AbYICXuM (ORCPT ); Wed, 3 Sep 2008 19:50:12 -0400 Received: from casper.infradead.org ([85.118.1.10]:36297 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752415AbYICXuL convert rfc822-to-8bit (ORCPT ); Wed, 3 Sep 2008 19:50:11 -0400 Date: Wed, 3 Sep 2008 16:50:14 -0700 From: Arjan van de Ven To: "J.A. =?UTF-8?B?TWFnYWxsw7Nu?=" Cc: Linux-Kernel Subject: Re: Finding what is stuck... Message-ID: <20080903165014.134cb5b9@infradead.org> In-Reply-To: <20080904010043.408b3f03@one.home> References: <20080902020447.5b48b083@one.home> <20080901170812.2c3b041b@infradead.org> <20080904010043.408b3f03@one.home> Organization: Intel X-Mailer: Claws Mail 3.5.0 (GTK+ 2.12.11; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 4 Sep 2008 01:00:43 +0200 "J.A. Magallón" wrote: > On Mon, 1 Sep 2008 17:08:12 -0700, Arjan van de Ven > wrote: > > > On Tue, 2 Sep 2008 02:04:47 +0200 > > "J.A. Magallón" wrote: > > > > > Hi all... > > > > > > I'm running 2.6.27-rc5-git2 on an Aspire One. > > > The system is in general pretty responsive, but sometimes it just > > > gets totally stuck. Even the mouse stops. > > > > > > It looks related to disk (SSD) access, but I'm not totally sure. > > > Is there any way to find what is getting stuck ? I know that SSDs > > > can be slow on write, I don't mind if the system is faster or > > > slower (it's small :))), but if the speed is constant. That > > > occasional pauses are strange, like if SSD flushing gets stuck on > > > BKL (I know, no idea about what I talk...). > > > > > > I'm using ext3 fs, noop iosched. But as I say, I'm not sure that > > > the disk writes are the culprit. > > > > > > Any idea about how to find this ? > > > > Have you tried to run "latencytop"? > > (you need to enable this in the kernel config as well) > > > > it tends to (for me at least) point out very well where stalls > > happen, or at least, what the system is doing when they happen. > > > > (hint: make sure you do "make install" before running it) > > > > These are some shots of latencytop while working. I copied the screen > when I saw any very high timing... > wow bad ones.. one thing to note.. you have *something* doing fsync() a lot it seems (latencytop is likely to tell you which one it is); fsync on ext3 is really expensive, especially on an ssd that is slow to write to. -- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org