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 94B5EC433EF for ; Wed, 23 Mar 2022 01:27:57 +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=uv0x7IhJh6HUYVs80OeWrM0ewUxdezb68rDatc83fOk=; b=X+J87KXnlf8HTtlH7LQzlftpQ2 Du6DnIxUqYpR0xRwKQEjLTlTaF/w+Y1KFWZowVxM9JnB3f/ETNlKbErRamXjFhNc8kRValDM3Z/qd Y03ofXjjF2wZeJ9k5g1KECJ3pHIeDhj7strLtTWGr2yiFH/hK9dL7r9OqPMY/sr+BIuIEkaoO5EnV 1MrcA1brfbiCxsYfSC2V+bRv7qW3Et2k9zhyZkFQC4H8b+jtJ5bQ7OMxi6UcEOWgGxCJEWPmltXNf IWIF9wjBS/k2wT/r70FXTiJzVb1MhUIrxoX7Y0Ghfr23e0VpcIrB8BYbrkbI0380gxr+ztmaXB3nr 8wC8nazA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nWpmx-00CZIP-7E; Wed, 23 Mar 2022 01:27:51 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nWpmu-00CZHV-2i for linux-nvme@lists.infradead.org; Wed, 23 Mar 2022 01:27:49 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1647998865; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=uv0x7IhJh6HUYVs80OeWrM0ewUxdezb68rDatc83fOk=; b=YpW6qXXV5yz6SnMskRPNMWw55hFnV2KVHG1fPZT7VNCH30bGJvg7FP3RyK1D5I0iHKioyF dPMRePGLgaZIzhvHf4+nPomgeDRnaZ5gUT0czAOBtCcLJIjrAeDVKBku8sbPn8A+Vsm7BM SvlliN+ukb7DHaRM0OVKscOwfCPs68E= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-508-pGai4B4ePTaoBfBKVAlgbw-1; Tue, 22 Mar 2022 21:27:40 -0400 X-MC-Unique: pGai4B4ePTaoBfBKVAlgbw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0E99C85A5BE; Wed, 23 Mar 2022 01:27:40 +0000 (UTC) Received: from T590 (ovpn-8-19.pek2.redhat.com [10.72.8.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E12497AD1; Wed, 23 Mar 2022 01:27:22 +0000 (UTC) Date: Wed, 23 Mar 2022 09:27:16 +0800 From: Ming Lei To: Kanchan Joshi Cc: Kanchan Joshi , Christoph Hellwig , Jens Axboe , Keith Busch , Pavel Begunkov , io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, sbates@raithlin.com, logang@deltatee.com, Pankaj Raghav , Javier =?iso-8859-1?Q?Gonz=E1lez?= , Luis Chamberlain , Adam Manzanares , Anuj Gupta Subject: Re: [PATCH 10/17] block: wire-up support for plugging Message-ID: References: <20220308152105.309618-1-joshi.k@samsung.com> <20220308152105.309618-11-joshi.k@samsung.com> <20220310083400.GD26614@lst.de> <20220321070208.GA5107@test-zns> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220321070208.GA5107@test-zns> X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220322_182748_238195_A390FE7E X-CRM114-Status: GOOD ( 22.43 ) 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 Mon, Mar 21, 2022 at 12:32:08PM +0530, Kanchan Joshi wrote: > On Mon, Mar 14, 2022 at 10:40:53PM +0800, Ming Lei wrote: > > On Thu, Mar 10, 2022 at 06:10:08PM +0530, Kanchan Joshi wrote: > > > On Thu, Mar 10, 2022 at 2:04 PM Christoph Hellwig wrote: > > > > > > > > On Tue, Mar 08, 2022 at 08:50:58PM +0530, Kanchan Joshi wrote: > > > > > From: Jens Axboe > > > > > > > > > > Add support to use plugging if it is enabled, else use default path. > > > > > > > > The subject and this comment don't really explain what is done, and > > > > also don't mention at all why it is done. > > > > > > Missed out, will fix up. But plugging gave a very good hike to IOPS. > > > > But how does plugging improve IOPS here for passthrough request? Not > > see plug->nr_ios is wired to data.nr_tags in blk_mq_alloc_request(), > > which is called by nvme_submit_user_cmd(). > > Yes, one tag at a time for each request, but none of the request gets > dispatched and instead added to the plug. And when io_uring ends the > plug, the whole batch gets dispatched via ->queue_rqs (otherwise it used > to be via ->queue_rq, one request at a time). > > Only .plug impact looks like this on passthru-randread: > > KIOPS(depth_batch) 1_1 8_2 64_16 128_32 > Without plug 159 496 784 785 > With plug 159 525 991 1044 > > Hope it does clarify. OK, thanks for your confirmation, then the improvement should be from batch submission only. If cached request is enabled, I guess the number could be better. Thanks, Ming