From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756618AbcIAVGy (ORCPT ); Thu, 1 Sep 2016 17:06:54 -0400 Received: from mx.ewheeler.net ([66.155.3.69]:35136 "EHLO mail.ewheeler.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750841AbcIAVGp (ORCPT ); Thu, 1 Sep 2016 17:06:45 -0400 Date: Thu, 1 Sep 2016 14:06:02 -0700 (PDT) From: Eric Wheeler X-X-Sender: lists@mail.ewheeler.net To: Mark Brown cc: Christoph Hellwig , Tejun Heo , Jens Axboe , Paolo Valente , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, ulf.hansson@linaro.org, linus.walleij@linaro.org, linux-bcache@vger.kernel.org, Omar Sandoval Subject: Re: [PATCH V2 00/22] Replace the CFQ I/O Scheduler with BFQ In-Reply-To: <20160831220949.GD5967@sirena.org.uk> Message-ID: References: <1470654917-4280-1-git-send-email-paolo.valente@linaro.org> <20160808131954.GA12647@infradead.org> <20160831220949.GD5967@sirena.org.uk> User-Agent: Alpine 2.11 (LRH 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 31 Aug 2016, Mark Brown wrote: [...] > I personally feel that given that it looks like this is all going to > take a while it'd still be good to merge BFQ at least as an alternative > scheduler so that people can take advantage of it while the work on > modernising everything to use blk-mq - that way we can hopefully improve > the state of the art for users in the short term or at least help get > some wider feedback on how well this works in the real world > independently of the work on blk-mq. I would like to chime in agree fervently with Mark. We have a pair of very busy hypervisors with a complicated block stack integrating bcache, drbd, LVM, dm-thin, kvm, ggaoed (AoE target), zram swap, continuous block-layer backups and snapshot verifies to tertiary storage, cgroup block IO throttled limits, and lots of hourly dm-thin snapshots replicated to tertiary storage. All of this is performed under heavy memory pressure (35-40% swapped out to zram). The systems work moderately well under cfq, but *amazingly well* using BFQ. I like BFQ so much that I've backported v8r2 to Linux v4.1 [1]. +1 to upstream this as a new scheduler without replacing CFQ. Including BFQ would be a boon for Linux and the community at large. -- Eric Wheeler [1] Based on Linux v4.1-rc1, it cleanly merges forward into v4.7: https://bitbucket.org/ewheelerinc/linux/branch/v4.1-rc1-bfq-v8 git pull https://bitbucket.org/ewheelerinc/linux.git v4.1-rc1-bfq-v8