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 6090DC43215 for ; Thu, 21 Nov 2019 15:56:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3904E206D8 for ; Thu, 21 Nov 2019 15:56:27 +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 S1727215AbfKUP4S (ORCPT ); Thu, 21 Nov 2019 10:56:18 -0500 Received: from mail-il1-f194.google.com ([209.85.166.194]:36384 "EHLO mail-il1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727208AbfKUP4R (ORCPT ); Thu, 21 Nov 2019 10:56:17 -0500 Received: by mail-il1-f194.google.com with SMTP id s75so3776168ilc.3 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=Lk91CHa/fDgSePD6/XFb6SHZb2IbIMr5xI1bRSPVjms7tcQlQjDxa0fYVExHyrZquG xXbxHi+Q0Vcqz2gBrLY2BUAZdxpnLsb8KUv8CWB0Pbs31is1gVNLiJKcEIL9F1rRxr5H ACjYkmUkGCpnS0yWe0aSgs3n6D0pSIL3mvn5JtZmRJxVp7EjGpGHXv7PuFBfla9i3mbw UdypyJeO58Ai3gbIebGuBYv/WYlWtXacDswR6AHGC4Eshy6XP74BqwK0Uxv8tP0/odca edX3c9WmBEsBYArgGafPwHDnirZXtQcYDU4IYHIspP+Ek9cNQ5o5JKdkrHG4EcJrKq2p in4Q== X-Gm-Message-State: APjAAAU4hXUWTykuB//VAyeefgDmlqV85uC0A7o997n2G2OVgQ+1MtFj keVjXhlY97Tzp5DuvHUWIpOKag== 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-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@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