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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4F724C25B4F for ; Fri, 10 May 2024 09:34:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=7KEHh32qBijNMwiNKkmLVLk33MaGaNI6oCDcJXjG8Wc=; b=p4dO3JbnK558Ozhgb9l630XxNt 51UALcbS6G6/fQFaEaFxG7GmoPT8Lg5z5PAu3PhyOtQKqpMz1c0bwNi7l6WjnWgbAwujiuUMaCTxo vgHiRRhOqL8yR2h2x6O76zFki/vdc29hn34bOFiP3Opxy5ZN6bG2cIuglrZ16rqrVxXs7f0fJXKlw oMlGiYw9nv2ufFiLmvN5xjkfGg4RIERJLsRJjlCLQD1Ai2ezzEcKg1udLNK3kDJqx4vp2Xfb5m1OZ 2efD6GhJ8kPHw50JRjPrWzPGQPGa7EjSX5IrAhPjloeR9iRBD4ZW1f5fCpY9Vhk7G+Gy/Y2ZfjhnD 7LKIJUyQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1s5MeH-00000004iJm-0At1; Fri, 10 May 2024 09:34:41 +0000 Received: from sin.source.kernel.org ([145.40.73.55]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1s5MeD-00000004iIq-3T4v for linux-nvme@lists.infradead.org; Fri, 10 May 2024 09:34:39 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id 4B234CE1CF3; Fri, 10 May 2024 09:34:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1F3B8C113CC; Fri, 10 May 2024 09:34:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1715333674; bh=fkKst5tRTPmG3SWpn0MZBr1yx/AoXoDQnBVjNHcEMhs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=g7UXPYPElwbH6RH2AbctTcL35+I6v0LHbxah7Qb0nxfHFh0PCe5zBFBuckuTCeszb GQsalXVhtQ6PfUF8bCkmcVWGgg8P0d3gMCWGuPNWXGWx/wR5LN1QJKgmSVnaUnRgWS yiuc0jxlH3sA6GPFbHlAaNYi9IJcU3chIloFPL027+FIEPajLPumlAntrtJC4DzkY5 thWGerpq92S8oGz5KVnXmyM0TFhzssV70mGZWDmyN30aywKkdc+fM9OMoTtO8aaThq uohhmfzP+YNpMCnVDjpiZl7Zp9L+CfNA92DlxcWa9KLsbbWBvHQQD4XLKtAvg7wLAq ab4exq9fijocA== Date: Fri, 10 May 2024 11:34:28 +0200 From: Niklas Cassel To: John Meneghini Cc: tj@kernel.org, josef@toxicpanda.com, axboe@kernel.dk, kbusch@kernel.org, hch@lst.de, sagi@grimberg.me, emilne@redhat.com, hare@kernel.org, linux-block@vger.kernel.org, cgroups@vger.kernel.org, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, jrani@purestorage.com, randyj@purestorage.com, aviv.coro@ibm.com Subject: Re: [PATCH v3 0/3] block,nvme: latency-based I/O scheduler Message-ID: References: <20240403141756.88233-1-hare@kernel.org> <20240509204324.832846-1-jmeneghi@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240509204324.832846-1-jmeneghi@redhat.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240510_023438_250678_FBC40035 X-CRM114-Status: GOOD ( 27.20 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Thu, May 09, 2024 at 04:43:21PM -0400, John Meneghini wrote: > I'm re-issuing Hannes's latency patches in preparation for LSFMM Hello John, Just a small note. Please don't reply-to the previous version of the series (v2), when sending out a v3. It creates "an unmanageable forest of references in email clients". See: https://www.kernel.org/doc/html/latest/process/submitting-patches.html#explicit-in-reply-to-headers Instead just add the url to the v2 on lore.kernel.org. See you at LSFMM! Kind regards, Niklas > > Changes since V2: > > I've done quite a bit of work cleaning up these patches. There were a > number of checkpatch.pl problems as well as some compile time errors > when config BLK_NODE_LATENCY was turned off. After the clean up I > rebased these patches onto Ewan's "nvme: queue-depth multipath iopolicy" > patches. This allowed me to test both iopolicy changes together. > > All of my test results, together with the scripts I used to generate these > graphs, are available at: > > https://github.com/johnmeneghini/iopolicy > > Please use the scripts in this repository to do your own testing. > > Changes since V1: > > Hi all, > > there had been several attempts to implement a latency-based I/O > scheduler for native nvme multipath, all of which had its issues. > > So time to start afresh, this time using the QoS framework > already present in the block layer. > It consists of two parts: > - a new 'blk-nlatency' QoS module, which is just a simple per-node > latency tracker > - a 'latency' nvme I/O policy > > Using the 'tiobench' fio script with 512 byte blocksize I'm getting > the following latencies (in usecs) as a baseline: > - seq write: avg 186 stddev 331 > - rand write: avg 4598 stddev 7903 > - seq read: avg 149 stddev 65 > - rand read: avg 150 stddev 68 > > Enabling the 'latency' iopolicy: > - seq write: avg 178 stddev 113 > - rand write: avg 3427 stddev 6703 > - seq read: avg 140 stddev 59 > - rand read: avg 141 stddev 58 > > Setting the 'decay' parameter to 10: > - seq write: avg 182 stddev 65 > - rand write: avg 2619 stddev 5894 > - seq read: avg 142 stddev 57 > - rand read: avg 140 stddev 57 > > That's on a 32G FC testbed running against a brd target, > fio running with 48 threads. So promises are met: latency > goes down, and we're even able to control the standard > deviation via the 'decay' parameter. > > As usual, comments and reviews are welcome. > > Changes to the original version: > - split the rqos debugfs entries > - Modify commit message to indicate latency > - rename to blk-nlatency > > Hannes Reinecke (2): > block: track per-node I/O latency > nvme: add 'latency' iopolicy > > John Meneghini (1): > nvme: multipath: pr_notice when iopolicy changes > > MAINTAINERS | 1 + > block/Kconfig | 9 + > block/Makefile | 1 + > block/blk-mq-debugfs.c | 2 + > block/blk-nlatency.c | 389 ++++++++++++++++++++++++++++++++++ > block/blk-rq-qos.h | 6 + > drivers/nvme/host/multipath.c | 73 ++++++- > drivers/nvme/host/nvme.h | 1 + > include/linux/blk-mq.h | 11 + > 9 files changed, 484 insertions(+), 9 deletions(-) > create mode 100644 block/blk-nlatency.c > > -- > 2.39.3 > >