From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Tso Subject: Re: ext4 unlink performance Date: Thu, 13 Nov 2008 15:42:40 -0500 Message-ID: <20081113204240.GF21652@mit.edu> References: <20081113185712.GB11204@untroubled.org> <20081113191000.GA11516@untroubled.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: linux-ext4@vger.kernel.org Return-path: Received: from www.church-of-our-saviour.org ([69.25.196.31]:36260 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750852AbYKMUmm (ORCPT ); Thu, 13 Nov 2008 15:42:42 -0500 Content-Disposition: inline In-Reply-To: <20081113191000.GA11516@untroubled.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, Nov 13, 2008 at 01:10:00PM -0600, Bruce Guenter wrote: > On Thu, Nov 13, 2008 at 12:57:12PM -0600, Bruce Guenter wrote: > > Ouch. Why is ext4 so much slower than ext3 here, > > I forgot to mention one important detail. I started running 'vmstat 5' > during one of the unlink runs, and noticed that there were intervals of > 15 or 20 seconds where no blocks were being read or written, and minimal > CPU was being used. I do not observe the same stalls when using ext3. Hmm... how very strange. Can you run the command: ps -eo pid,tid,class,rtprio,ni,pri,psr,pcpu,stat,wchan:16,comm during one of the quiescent periods, and see what is in the WCHAN field for the unlink command? - Ted