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=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 74F5FC432C0 for ; Thu, 21 Nov 2019 15:56:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4C5FE206EC for ; Thu, 21 Nov 2019 15:56:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="p9f61F2q" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727261AbfKUP41 (ORCPT ); Thu, 21 Nov 2019 10:56:27 -0500 Received: from mail-il1-f195.google.com ([209.85.166.195]:35764 "EHLO mail-il1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727205AbfKUP4S (ORCPT ); Thu, 21 Nov 2019 10:56:18 -0500 Received: by mail-il1-f195.google.com with SMTP id z12so3769968ilp.2 for ; Thu, 21 Nov 2019 07:56:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=i6XZTTQSHJKM+KBZCHJbpNr3leYiOU/zZyc4Kt/q1ls=; b=p9f61F2qEE4/QwqhzVpQxRpsxX+tV3SxRebeynsmRfBNHvoMnRcPAeQBMJ4vetLpDz shfSAjNsSLR8/AyOjsQjN2cfgMUQmKjudar8cuqkQT4utDF/Fg0xyKUILGxfQL2m4ykC v2dKDPfCeTVXelv8ErH8wWKv+orr2ysEDzISJsEE+qs4wfsyfactwDmLH8MnBWJzVSmY XCTDegH0huTSluHvW6LcnV5C2iycu99pwuw2Q/YxucMfTo227eo59/I8ZMNVpzMswrI3 2Efr4431bVIGY+4pWPJ+b3TiJoIazJewBg9vmPs5YlVPxg8N869vnJ+tezxnZ3CO4XTi 5d9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=i6XZTTQSHJKM+KBZCHJbpNr3leYiOU/zZyc4Kt/q1ls=; b=et0VHgg2l30f+F1AI+g13pn8KdsJXw7aMFTiNcJjCKsgQ7TBYd+gqSPEcgup4YS6V5 3+NORF3SjRKzCQC8wvO6yoKww5edTwCYZkjcaepR8tyxZkqUTSDrufEmFuyNyUIdC13f Yza+H7Cv/QT0b8H87INAsKRnLHcL4ofJVlOup3VOb9iMovz6Ind/rWDPybuWwhrhaiFN nVxD28eu71XQ8YhgkyiTARq6gGAkc+8IW1f8TkD9K2kfUSZmaEqticjh+AWDyKQF8jUg q05o8Z1kI4km6HMQIBVX8X3awU3URL7t4Ta8/HCj/zU+ZVm6fuTUSg4oN6ITqW+IPvYu ccyw== X-Gm-Message-State: APjAAAUVnwA/QXeXXoeh05dhRPYy5GVW9dgXaCcJaE1SEI6l6FcRnwQE vo0QWZmOVxSwYoBv2L0DIsCzMA== X-Google-Smtp-Source: APXvYqyBx1nTqGMRn9GsWSj0/giOcMCoKn/OjZ4stbz+xyyRba03IeYJrruyiFFcHRXe1jGKDNx4oA== X-Received: by 2002:a05:6e02:100b:: with SMTP id n11mr10655778ilj.212.1574351776819; Thu, 21 Nov 2019 07:56:16 -0800 (PST) Received: from [192.168.1.159] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id 133sm1342001ila.25.2019.11.21.07.56.15 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 21 Nov 2019 07:56:15 -0800 (PST) Subject: Re: [PATCH] block: add iostat counters for flush requests To: Konstantin Khlebnikov , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, Dmitry Monakhov References: <157433282607.7928.5202409984272248322.stgit@buzz> From: Jens Axboe Message-ID: Date: Thu, 21 Nov 2019 08:56:14 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <157433282607.7928.5202409984272248322.stgit@buzz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 11/21/19 3:40 AM, Konstantin Khlebnikov wrote: > Requests that triggers flushing volatile writeback cache to disk (barriers) > have significant effect to overall performance. > > Block layer has sophisticated engine for combining several flush requests > into one. But there is no statistics for actual flushes executed by disk. > Requests which trigger flushes usually are barriers - zero-size writes. > > This patch adds two iostat counters into /sys/class/block/$dev/stat and > /proc/diskstats - count of completed flush requests and their total time. This makes sense to me, and the "recent" discard addition already proved that we're fine extending with more fields. Unless folks object, I'd be happy to queue this up for 5.5. -- Jens Axboe