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_PASS,URIBL_BLOCKED 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 69164C00449 for ; Wed, 3 Oct 2018 15:54:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 31BE82098A for ; Wed, 3 Oct 2018 15:54:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 31BE82098A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=acm.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727420AbeJCWnw (ORCPT ); Wed, 3 Oct 2018 18:43:52 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:36072 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726801AbeJCWnv (ORCPT ); Wed, 3 Oct 2018 18:43:51 -0400 Received: by mail-pl1-f196.google.com with SMTP id y11-v6so543821plt.3; Wed, 03 Oct 2018 08:54:53 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=XTy9mH10pGGBZxkkteDIvQMExuu/zavR1jJVhkIG9Ak=; b=emW8Uf8v/qRBoOax8+crNyDk4VDzoO6uVrkvjzIFm0ttrS/4eYbSaVUGmFTM+pxjhq Q9I4wbjvlvl6Hnp0+Oh9aSXd/8QcOd3DyNtr7g6cXBPhYo/gzaSlYbnZRVnbcmw0jy2l 1Ljrch6bCV4g1xCkuqXPOgdn42LcJLEsT7ahtDwkd9o6ERX38zPYe00HBd46ocQB6U9K ov6t2m6vuFNvhHDkalOtatsLHwYGRFBsWcVkg8iwpFk6H0CbeYNIK8bMs3+U0IK3Ihjx PxXInHalQW2lTf6vhwYzaGWvecw1GE1aJyyA99Qewnq6/rOQuJ2Ekqdk2t6aJ354n1K1 fheQ== X-Gm-Message-State: ABuFfoic826KkHlFMCxXAKJqFsqBt9HFDBB5BlgeBLMkchP8iNOsAIBr +MMwCVzoPKNz6VBZ66R4ZBQ= X-Google-Smtp-Source: ACcGV62Ue1Hc4oRKlU/90ONTZc+/T3P39i2c7G+QpZH9E277Vw+ei2VVyfmE+pp6P13l87Uc/hwtcQ== X-Received: by 2002:a17:902:101:: with SMTP id 1-v6mr2287930plb.15.1538582093356; Wed, 03 Oct 2018 08:54:53 -0700 (PDT) Received: from ?IPv6:2620:15c:2cd:203:5cdc:422c:7b28:ebb5? ([2620:15c:2cd:203:5cdc:422c:7b28:ebb5]) by smtp.gmail.com with ESMTPSA id m15-v6sm7198918pfk.149.2018.10.03.08.54.52 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 03 Oct 2018 08:54:52 -0700 (PDT) Message-ID: <1538582091.205649.20.camel@acm.org> Subject: Re: [PATCH] block: BFQ default for single queue devices From: Bart Van Assche To: Paolo Valente , Jens Axboe Cc: Linus Walleij , linux-block , linux-mmc , linux-mtd@lists.infradead.org, Pavel Machek , Ulf Hansson , Richard Weinberger , Artem Bityutskiy , Adrian Hunter , Jan Kara , Andreas Herrmann , Mel Gorman , Chunyan Zhang , linux-kernel , 'Paolo Valente' via bfq-iosched , Oleksandr Natalenko , Mark Brown Date: Wed, 03 Oct 2018 08:54:51 -0700 In-Reply-To: References: <20181002124329.21248-1-linus.walleij@linaro.org> <05fdbe23-ec01-895f-e67e-abff85c1ece2@kernel.dk> Content-Type: text/plain; charset="UTF-7" X-Mailer: Evolution 3.26.2-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2018-10-03 at 08:29 +-0200, Paolo Valente wrote: +AD4 +AFs-1+AF0 https://lkml.org/lkml/2017/2/21/791 +AD4 +AFs-2+AF0 http://algo.ing.unimo.it/people/paolo/disk+AF8-sched/results.php +AD4 +AFs-3+AF0 https://lwn.net/Articles/763603/ >From +AFs-2+AF0: +ACI-BFQ loses about 18+ACU with only random readers, because the number of IOPS becomes so high that the execution time and parallel efficiency of the schedulers becomes relevant.+ACI Since the number of I/O patterns for which results are available on +AFs-2+AF0 is limited and since the number of devices for which test results are available on +AFs-2+AF0 is limited (e.g. RAID is missing), there might be other cases in which configuring BFQ as the default would introduce a regression. I agree with Jens that it's best to leave it to the Linux distributors to select a default I/O scheduler. Bart.