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 E7181CD1288 for ; Thu, 4 Apr 2024 21:14:40 +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=e+TWigf5NcPvyOnw7saZvcMkm/5biXuUhOhLWHqSS0w=; b=beI3r8lMkKN0HMBFlgbXdwpA1g eOpeWIjEfRe8G3RxByLgQB2aw67sTncrazdRoJGEjQ5N1jLTeiOOxwK/7+SfucrMCi57inycPEpjU MNyeFSpbI1vo+fTe7ZXL4AqH+noSzRmJNEh0i8tt3oIF3Vhwl7OXmbry+iYmYzU22HfELkNa8AD0g SKdIsGDuCI1g0XqzRxzEDPG7LyTd3hq2scMLS7aeCqD1QVb4pjZ0amBUH1urvxpdo/zm2PDGN07e7 4gYvIrk4oyQorpH+rHJvKnGn4Unrc35IlyX8D1boE81gT5NjqmDpy3+QUYsSPlZl6b8PpqjklzJGZ m9ydl8wA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rsUPt-00000004I37-1gCw; Thu, 04 Apr 2024 21:14:37 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rsUPq-00000004I2b-0mkq for linux-nvme@lists.infradead.org; Thu, 04 Apr 2024 21:14:35 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 399F761770; Thu, 4 Apr 2024 21:14:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 70986C433F1; Thu, 4 Apr 2024 21:14:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712265272; bh=ciwjEoIduPsk7nGPQqW7xbd2pM/oT+BddQO32l5bDI8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YlLQtw2rbxj/SuR1EodSXMB9fpwJpwKRjwZiDfgj7XcMOblH3KrcFqEuKUU6oWhpR KIWfMmJM8wQrHCswrKvjmWuqeK4z8gP3eT/WOIe2/1rRokEVtXs9j8KZoQli3/nhsU YR7H1emuAlIk6fo4rRugY56o0twaMthpzJjOZCX3FUB3G+hagaKpLWa9MTlQGUi+jH jsdTjk9dUBiONouoY+Y5jyPkVKvQiGkUrzjYeaTO4JLN+mWTPYk0OZDx6B9KfxbX4c 5Y6SzEp8P56KojsL1CxxJjGx2iHvfrUVjN4B7um9g5vqchAkqFiWFaE/aT3Kka4e1a OAf271BSPScAQ== Date: Thu, 4 Apr 2024 15:14:30 -0600 From: Keith Busch To: Hannes Reinecke Cc: Christoph Hellwig , Sagi Grimberg , Jens Axboe , linux-nvme@lists.infradead.org, linux-block@vger.kernel.org Subject: Re: [PATCHv2 0/2] block,nvme: latency-based I/O scheduler Message-ID: References: <20240403141756.88233-1-hare@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240403141756.88233-1-hare@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240404_141434_293096_7AF19EC4 X-CRM114-Status: GOOD ( 11.25 ) 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 Wed, Apr 03, 2024 at 04:17:54PM +0200, Hannes Reinecke wrote: > 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 Whatever happened with the io-depth based path selector? That should naturally align with the lower latency path, and that metric is cheaper to track.