Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757034AbZJHCTU (ORCPT ); Wed, 7 Oct 2009 22:19:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756787AbZJHCTU (ORCPT ); Wed, 7 Oct 2009 22:19:20 -0400 Received: from mail.valinux.co.jp ([210.128.90.3]:56093 "EHLO mail.valinux.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756748AbZJHCTT (ORCPT ); Wed, 7 Oct 2009 22:19:19 -0400 Date: Thu, 08 Oct 2009 11:18:41 +0900 (JST) Message-Id: <20091008.111841.226773827.ryov@valinux.co.jp> To: vgoyal@redhat.com Cc: nauman@google.com, m-ikeda@ds.jp.nec.com, linux-kernel@vger.kernel.org, jens.axboe@oracle.com, containers@lists.linux-foundation.org, dm-devel@redhat.com, dpshah@google.com, lizf@cn.fujitsu.com, mikew@google.com, fchecconi@gmail.com, paolo.valente@unimore.it, fernando@oss.ntt.co.jp, s-uchida@ap.jp.nec.com, taka@valinux.co.jp, guijianfeng@cn.fujitsu.com, jmoyer@redhat.com, dhaval@linux.vnet.ibm.com, balbir@linux.vnet.ibm.com, righi.andrea@gmail.com, agk@redhat.com, akpm@linux-foundation.org, peterz@infradead.org, jmarchan@redhat.com, torvalds@linux-foundation.org, mingo@elte.hu, riel@redhat.com, yoshikawa.takuya@oss.ntt.co.jp Subject: Re: IO scheduler based IO controller V10 From: Ryo Tsuruta In-Reply-To: <20091007150929.GB3674@redhat.com> References: <20091006112201.GA27866@redhat.com> <20091007.233805.183040347.ryov@valinux.co.jp> <20091007150929.GB3674@redhat.com> X-Mailer: Mew version 5.2.52 on Emacs 22.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3878 Lines: 82 Hi Vivek, Vivek Goyal wrote: > Ok. Our numbers can vary a bit depending on fio settings like block size > and underlying storage also. But that's not the important thing. Currently > with this test I just wanted to point out that model of ioprio with-in group > is currently broken with dm-ioband and good that you can reproduce that. > > One minor nit, for max latency you need to look at "clat " row and "max=" field > in fio output. Most of the time "max latency" will matter most. You seem to > be currently grepping for "maxt" which is just seems to be telling how > long did test run and in this case 30 seconds. > > Assigning reads to right context in CFQ and not to dm-ioband thread might > help a bit, but I am bit skeptical and following is the reason. > > CFQ relies on time providing longer time slice length for higher priority > process and if one does not use time slice, it looses its share. So the moment > you buffer even single bio of a process in dm-layer, if CFQ was servicing that > process at same time, that process will loose its share. CFQ will at max > anticipate for 8 ms and if buffering is longer than 8ms, CFQ will expire the > queue and move on to next queue. Later if you submit same bio and with > dm-ioband helper thread and even if CFQ attributes it to right process, it is > not going to help much as process already lost it slice and now a new slice > will start. O.K. I would like to figure something out this issue. > > > > Be that as it way, I think that if every bio can point the iocontext > > > > of the process, then it makes it possible to handle IO priority in the > > > > higher level controller. A patchse has already posted by Takhashi-san. > > > > What do you think about this idea? > > > > > > > > Date Tue, 22 Apr 2008 22:51:31 +0900 (JST) > > > > Subject [RFC][PATCH 1/10] I/O context inheritance > > > > From Hirokazu Takahashi <> > > > > http://lkml.org/lkml/2008/4/22/195 > > > > > > So far you have been denying that there are issues with ioprio with-in > > > group in higher level controller. Here you seems to be saying that there are > > > issues with ioprio and we need to take this patch in to solve the issue? I am > > > confused? > > > > The true intention of this patch is to preserve the io-context of a > > process which originate it, but I think that we could also make use of > > this patch for one of the way to solve this issue. > > > > Ok. Did you run the same test with this patch applied and how do numbers look > like? Can you please forward port it to 2.6.31 and I will also like to > play with it? I'm sorry, I have no time to do that this week. I would like to do the forward porting and test with it by the mini-summit when poissible. > I am running more tests/numbers with 2.6.31 for all the IO controllers and > planning to post it to lkml before we meet for IO mini summit. Numbers can > help us understand the issue better. > > In first phase I am planning to post numbers for IO scheudler controller > and dm-ioband. Then will get to max bw controller of Andrea Righi. That sounds good. Thank you for your work. > > I created those patches against 2.6.32-rc1 and made sure the patches > > can be cleanly applied to that version. > > I am applying dm-ioband patch first and then bio cgroup patches. Is this > right order? Will try again. Yes, the order is right. Here are the sha1sums. 9f4e50878d77922c84a29be9913a8b5c3f66e6ec linux-2.6.32-rc1.tar.bz2 15d7cc9d801805327204296a2454d6c5346dd2ae dm-ioband-1.14.0.patch 5e0626c14a40c319fb79f2f78378d2de5cc97b02 blkio-cgroup-v13.tar.bz2 Thanks, Ryo Tsuruta -- 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/