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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 B2378C43331 for ; Wed, 13 Nov 2019 03:17:18 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 83A33222BD for ; Wed, 13 Nov 2019 03:17:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="OeXJ0Jpg"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="PvWJSQO+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 83A33222BD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=x2p70OzttPYasURC2C6vdNybTN12vzLj9GRKgEwTgC8=; b=OeXJ0JpgkOpaTv HP30BlFY/MxM/z1q6tErfZCh3hxuOpuwjnUOiJJUa+dir1WFzqHe2/tlwhn+EZV/f5zPQo5DxJMbv koW/FHYhG+R3Fi3GsJS1EMOdhNkvm10TxzXLpJKOyiaBYw1dBNJK5b5aYY/nHw+FS0OoknXcxhUb8 dla+YVQXHbxM199ZuO4oV9EcvnYgAyDnMnKshuw+aO6VaTBNCJ+canKRAfsNnGrBOty74nvpJZloO 9IxPKEc+46md0svZrcDn8R17xxUo8KqqC1bLasydMn41IX5eb1M7Hm5KhpjMXllmTOojDM6TwueKu qMyy35lyqzMnXdoGx1Wg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iUj9g-0002wY-Ap; Wed, 13 Nov 2019 03:17:16 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iUj9d-0002wE-ID for linux-nvme@lists.infradead.org; Wed, 13 Nov 2019 03:17:14 +0000 Received: from redsun51.ssa.fujisawa.hgst.com (unknown [199.255.47.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A191A222C2; Wed, 13 Nov 2019 03:17:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573615030; bh=uHvtNuhudWInBNglzR2Ch8Kpe7/M+liPClmU7l3pi1g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=PvWJSQO+JLfNlGWW0ARsHxRzr9C8w467PgnrYrstOJaNsNgta34gHvfcPyhFQcdam mgy6vlBfKZSGhUx3IFy521x1PL55+4AsPUdfGOvuWUBQRsZdHmXWAQEpyb+DoOsxCg sPSD/feB9jD3ow8JYVlRKcZ8znp8wN85tZ9+V0Ik= Date: Wed, 13 Nov 2019 12:17:02 +0900 From: Keith Busch To: Ming Lei Subject: Re: [PATCH 2/2] nvme-pci: poll IO after batch submission for multi-mapping queue Message-ID: <20191113031702.GA25906@redsun51.ssa.fujisawa.hgst.com> References: <20191108035508.26395-1-ming.lei@redhat.com> <20191108035508.26395-3-ming.lei@redhat.com> <20191111204446.GA26028@lst.de> <20191112023920.GD15079@ming.t460p> <8198fd99-6b47-7594-ba1c-4a15ffe25269@suse.de> <20191112164947.GB29135@redsun51.ssa.fujisawa.hgst.com> <20191113030520.GC28701@ming.t460p> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191113030520.GC28701@ming.t460p> User-Agent: Mutt/1.12.1 (2019-06-15) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191112_191713_624253_978E300F X-CRM114-Status: UNSURE ( 8.59 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sagi Grimberg , Long Li , "linux-nvme@lists.infradead.org" , Jens Axboe , Hannes Reinecke , Christoph Hellwig Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Wed, Nov 13, 2019 at 11:05:20AM +0800, Ming Lei wrote: > Threaded irq can't help Azure's performance, because Azure's nvme implementation > applies aggressive interrupt coalescing. This sounds like QD1 latency is really awful if it's coalescing this way. Let me restate to ensure I understand how this patch addresses the high-depth case: by polling during submission, a multi-threaded high depth workload gets to carve up the number of CQEs handled by spreading across more CPUs. Real hardware should see fewer completions per interrupt, but we should be able to recreate this issue by enabling interrupt coalescing on a real NVMe. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme