From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41ED3C31E44 for ; Tue, 11 Jun 2019 22:35:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E80A2173B for ; Tue, 11 Jun 2019 22:35:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405845AbfFKWfG (ORCPT ); Tue, 11 Jun 2019 18:35:06 -0400 Received: from outgoing-stata.csail.mit.edu ([128.30.2.210]:35276 "EHLO outgoing-stata.csail.mit.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405174AbfFKWfG (ORCPT ); Tue, 11 Jun 2019 18:35:06 -0400 Received: from [4.30.142.84] (helo=srivatsab-a01.vmware.com) by outgoing-stata.csail.mit.edu with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.82) (envelope-from ) id 1hapM2-0004FG-TW; Tue, 11 Jun 2019 18:34:59 -0400 Subject: Re: CFQ idling kills I/O performance on ext4 with blkio cgroup controller From: "Srivatsa S. Bhat" To: Paolo Valente Cc: linux-fsdevel@vger.kernel.org, linux-block , linux-ext4@vger.kernel.org, cgroups@vger.kernel.org, kernel list , Jens Axboe , Jan Kara , Jeff Moyer , Theodore Ts'o , amakhalov@vmware.com, anishs@vmware.com, srivatsab@vmware.com, Ulf Hansson , Linus Walleij References: <8d72fcf7-bbb4-2965-1a06-e9fc177a8938@csail.mit.edu> <5B6570A2-541A-4CF8-98E0-979EA6E3717D@linaro.org> <2CB39B34-21EE-4A95-A073-8633CF2D187C@linaro.org> <0e3fdf31-70d9-26eb-7b42-2795d4b03722@csail.mit.edu> <686D6469-9DE7-4738-B92A-002144C3E63E@linaro.org> <01d55216-5718-767a-e1e6-aadc67b632f4@csail.mit.edu> <6FE0A98F-1E3D-4EF6-8B38-2C85741924A4@linaro.org> <2A58C239-EF3F-422B-8D87-E7A3B500C57C@linaro.org> <5b71028c-72f0-73dd-0cd5-f28ff298a0a3@csail.mit.edu> <0d6e3c02-1952-2177-02d7-10ebeb133940@csail.mit.edu> <7B74A790-BD98-412B-ADAB-3B513FB1944E@linaro.org> <6a6f4aa4-fc95-f132-55b2-224ff52bd2d8@csail.mit.edu> Message-ID: <7c5e9d11-4a3d-7df4-c1e6-7c95919522ab@csail.mit.edu> Date: Tue, 11 Jun 2019 15:34:48 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <6a6f4aa4-fc95-f132-55b2-224ff52bd2d8@csail.mit.edu> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 6/2/19 12:04 AM, Srivatsa S. Bhat wrote: > On 5/30/19 3:45 AM, Paolo Valente wrote: >> [...] >> At any rate, since you pointed out that you are interested in >> out-of-the-box performance, let me complete the context: in case >> low_latency is left set, one gets, in return for this 12% loss, >> a) at least 1000% higher responsiveness, e.g., 1000% lower start-up >> times of applications under load [1]; >> b) 500-1000% higher throughput in multi-client server workloads, as I >> already pointed out [2]. >> > > I'm very happy that you could solve the problem without having to > compromise on any of the performance characteristics/features of BFQ! > > >> I'm going to prepare complete patches. In addition, if ok for you, >> I'll report these results on the bug you created. Then I guess we can >> close it. >> > > Sounds great! > Hi Paolo, Hope you are doing great! I was wondering if you got a chance to post these patches to LKML for review and inclusion... (No hurry, of course!) Also, since your fixes address the performance issues in BFQ, do you have any thoughts on whether they can be adapted to CFQ as well, to benefit the older stable kernels that still support CFQ? Thank you! Regards, Srivatsa VMware Photon OS