From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756701Ab0IGMgY (ORCPT ); Tue, 7 Sep 2010 08:36:24 -0400 Received: from hera.kernel.org ([140.211.167.34]:52046 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756256Ab0IGMgT (ORCPT ); Tue, 7 Sep 2010 08:36:19 -0400 Message-ID: <4C8631BE.9030709@kernel.org> Date: Tue, 07 Sep 2010 14:36:14 +0200 From: Tejun Heo User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.2.8) Gecko/20100802 Thunderbird/3.1.2 MIME-Version: 1.0 To: Jens Axboe CC: Christoph Hellwig , "linux-kernel@vger.kernel.org" Subject: Re: [PATCHSET] backing-dev: replace private thread pool with workqueue References: <1283777182-11426-1-git-send-email-tj@kernel.org> <20100907121608.GA26597@lst.de> <4C862DDC.6010702@kernel.org> <4C86303A.90601@fusionio.com> In-Reply-To: <4C86303A.90601@fusionio.com> X-Enigmail-Version: 1.1.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Tue, 07 Sep 2010 12:36:16 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On 09/07/2010 02:29 PM, Jens Axboe wrote: > I agree (with both of you). It's definitely too early to convert it > over, but if we can in the longer run, it never hurts to get rid of > code. The writeback threads aren't a typical threadpool, in that the > threads stick around and only go away when idle for too long. If they > stick around, you get the same process hammering IO at your device. So > converting that over to the generic cwq may or may not be at a > performance cost, it'll definitely have to be tested. One thing to try is removing WQ_UNBOUND and see how it affects the performance. I put WQ_UNBOUND there mainly to keep the behavior about the same as the current code but given what it does I think it would probably fare better with workers bound to CPUs. Thanks. -- tejun