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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,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 C28F8C432C0 for ; Thu, 21 Nov 2019 16:04:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 96A5320637 for ; Thu, 21 Nov 2019 16:04:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="fZqcwRu6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727116AbfKUQEi (ORCPT ); Thu, 21 Nov 2019 11:04:38 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:38190 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726983AbfKUQEh (ORCPT ); Thu, 21 Nov 2019 11:04:37 -0500 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xALFsQCU042866; Thu, 21 Nov 2019 16:04:34 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2019-08-05; bh=lPdzRkGQjx1NBncVBBW08mF7iSdoj3OKKNLTrQgVL1A=; b=fZqcwRu6/297MXYL4AQrhH652KbdWwYD5hkeAy3ANx2APi7pkzdLg2SEwSEKnXtnhm/l LP6sE5fDyy5cE1nuIVpJvi5e4fwn67KAcDpeHFbnnjNZa4EPf9o6cUhNYzjxeXoO5Wg/ 0IN166/jwdzGKEzEkS04DtxbO3+eG8bKHoiQVb+oyzGmTYa6vlikByCUrUfqERMq/bgM ET3Zr4/lXjs3VoUgpQ8fHu/inSnjeLRiTkTpacdJQUCqoZm5Y66RkZJf31vL0x93nw9w DebbKqkWFPgSI4s77cSm0Em66OEoPtGbtnyoIpk3VlZp3IMPIY2jkCWZE2HOSxOi09FM 6A== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by aserp2120.oracle.com with ESMTP id 2wa92q58kp-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 21 Nov 2019 16:04:34 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xALFquan057588; Thu, 21 Nov 2019 16:04:34 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3020.oracle.com with ESMTP id 2wdfrtfur2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 21 Nov 2019 16:04:33 +0000 Received: from abhmp0014.oracle.com (abhmp0014.oracle.com [141.146.116.20]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id xALG4WhA010611; Thu, 21 Nov 2019 16:04:32 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 21 Nov 2019 08:04:31 -0800 Date: Thu, 21 Nov 2019 08:04:30 -0800 From: "Darrick J. Wong" To: Jens Axboe 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 Subject: Re: [PATCH] block: add iostat counters for flush requests Message-ID: <20191121160430.GJ6211@magnolia> References: <157433282607.7928.5202409984272248322.stgit@buzz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9447 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1911210142 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9447 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1911210142 Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org 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... :) --D > -- > Jens Axboe >