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 193B4C432C3 for ; Thu, 21 Nov 2019 16:07:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E47B3206EC for ; Thu, 21 Nov 2019 16:07:33 +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="MRC5GtQY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726714AbfKUQH3 (ORCPT ); Thu, 21 Nov 2019 11:07:29 -0500 Received: from mail-il1-f193.google.com ([209.85.166.193]:34791 "EHLO mail-il1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726541AbfKUQH3 (ORCPT ); Thu, 21 Nov 2019 11:07:29 -0500 Received: by mail-il1-f193.google.com with SMTP id p6so3830094ilp.1 for ; Thu, 21 Nov 2019 08:07:28 -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=P4W4hyYZ6T+wL1O213mYLd96KdBzBHpg9/YQCjoVILM=; b=MRC5GtQYRbjWjFGZ/vJsaClUMDJ7hy8XeLThYplbe7u/VBoJyVDfOQRYNCc9WHf1+R YM8i3LUmqrCtDbaOPuE+/759ibNWitWsdr/1LB32m8NQp+rYS/R5MRMYP0SxrAH7pDW/ yzbDF1xvKxuXI/4YwDImOAMRtkxOBtfLCZb7Rn0Rg5lGNiLHY69oLwDT8tQHHONCPyOL VRRMjJIF0O4osgapAp43czNPYKTjL442yIx7Ljhmy1ctls9w6UWWmnJ6QyM6DqVy3hqf 4k0Yi51vruRfdY62Nc1rpQ3KoiUObEVajgdICck/bxmpkaj8MaFGqq96EHvYxa8LmC1u C7Og== 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=P4W4hyYZ6T+wL1O213mYLd96KdBzBHpg9/YQCjoVILM=; b=kqUCoyI2O6lKnt6KmhRGN0updXWowDYpzN4n4HnexcXjhAzq/XERJ8k8GBmPZu78mQ 69OonDlXxRn+S9/wWkNCIxx18z6JiJCBMEFdUFVcxogby5X6xodtyOkd5UmBPtqWgRPP jr6YCZJJupeVOGDL6FlISceIGwjzJZyA4MxXQanpRC3c5Xxdvw8mZAbg8qxEJkosCAj/ YXi2/Q+dRrNgLdCILqtuidmrQC/qeWxFoIC5ED04dCitP8LmUDdEzY0ssmUfgoH8XRQ8 srsPUGRkFdZ4ueOtY74T4BjDGAJT4TfflwUTq9iPgGrd3tCJ1BV6YDyH7IVYWCk7JKBT w8eg== X-Gm-Message-State: APjAAAUmy4YYO7/s6FcdJXhWR7Nt70kXX/LW8xvhfhoIwj3ubXwDlelS YeCdAjiTDOriYJT279iB8crMVg== X-Google-Smtp-Source: APXvYqwBuxR5GnmNrTTF+fDPqQ/m+MVGAFtj5D46hjZm7URBjIHtPwDjypsu1kC4QDIwCYtLqK4NhA== X-Received: by 2002:a92:9ace:: with SMTP id c75mr11197162ill.296.1574352448192; Thu, 21 Nov 2019 08:07:28 -0800 (PST) Received: from [192.168.1.159] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id v15sm1379208ilk.8.2019.11.21.08.07.26 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 21 Nov 2019 08:07:27 -0800 (PST) Subject: Re: [PATCH] block: add iostat counters for flush requests To: "Darrick J. Wong" Cc: Konstantin Khlebnikov , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, Dmitry Monakhov References: <157433282607.7928.5202409984272248322.stgit@buzz> <20191121160430.GJ6211@magnolia> From: Jens Axboe Message-ID: Date: Thu, 21 Nov 2019 09:07:26 -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: <20191121160430.GJ6211@magnolia> 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 9:04 AM, Darrick J. Wong wrote: > On Thu, Nov 21, 2019 at 08:56:14AM -0700, Jens Axboe wrote: >> 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. > > Looks like a good addition to /me... :) That's all the encouragement I needed, added :-) -- Jens Axboe