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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 54058C43381 for ; Thu, 21 Mar 2019 17:08:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1A4A0218B0 for ; Thu, 21 Mar 2019 17:08:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728656AbfCURIG (ORCPT ); Thu, 21 Mar 2019 13:08:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20224 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727958AbfCURIG (ORCPT ); Thu, 21 Mar 2019 13:08:06 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id ED1E583F3A; Thu, 21 Mar 2019 17:08:05 +0000 (UTC) Received: from maximlenovopc.usersys.redhat.com (unknown [10.35.206.30]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8254F5D9C5; Thu, 21 Mar 2019 17:07:40 +0000 (UTC) Message-ID: Subject: Re: your mail From: Maxim Levitsky To: Stefan Hajnoczi Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Jens Axboe , Alex Williamson , Keith Busch , Christoph Hellwig , Sagi Grimberg , Kirti Wankhede , "David S . Miller" , Mauro Carvalho Chehab , Greg Kroah-Hartman , Wolfram Sang , Nicolas Ferre , "Paul E . McKenney" , Paolo Bonzini , Liang Cunming , Liu Changpeng , Fam Zheng , Amnon Ilan , John Ferlan Date: Thu, 21 Mar 2019 19:07:38 +0200 In-Reply-To: <20190321161352.GA21682@stefanha-x1.localdomain> References: <20190319144116.400-1-mlevitsk@redhat.com> <20190321161352.GA21682@stefanha-x1.localdomain> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 21 Mar 2019 17:08:06 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2019-03-21 at 16:13 +0000, Stefan Hajnoczi wrote: > On Tue, Mar 19, 2019 at 04:41:07PM +0200, Maxim Levitsky wrote: > > Date: Tue, 19 Mar 2019 14:45:45 +0200 > > Subject: [PATCH 0/9] RFC: NVME VFIO mediated device > > > > Hi everyone! > > > > In this patch series, I would like to introduce my take on the problem of > > doing > > as fast as possible virtualization of storage with emphasis on low latency. > > > > In this patch series I implemented a kernel vfio based, mediated device > > that > > allows the user to pass through a partition and/or whole namespace to a > > guest. > > > > The idea behind this driver is based on paper you can find at > > https://www.usenix.org/conference/atc18/presentation/peng, > > > > Although note that I stared the development prior to reading this paper, > > independently. > > > > In addition to that implementation is not based on code used in the paper > > as > > I wasn't being able at that time to make the source available to me. > > > > ***Key points about the implementation:*** > > > > * Polling kernel thread is used. The polling is stopped after a > > predefined timeout (1/2 sec by default). > > Support for all interrupt driven mode is planned, and it shows promising > > results. > > > > * Guest sees a standard NVME device - this allows to run guest with > > unmodified drivers, for example windows guests. > > > > * The NVMe device is shared between host and guest. > > That means that even a single namespace can be split between host > > and guest based on different partitions. > > > > * Simple configuration > > > > *** Performance *** > > > > Performance was tested on Intel DC P3700, With Xeon E5-2620 v2 > > and both latency and throughput is very similar to SPDK. > > > > Soon I will test this on a better server and nvme device and provide > > more formal performance numbers. > > > > Latency numbers: > > ~80ms - spdk with fio plugin on the host. > > ~84ms - nvme driver on the host > > ~87ms - mdev-nvme + nvme driver in the guest > > You mentioned the spdk numbers are with vhost-user-nvme. Have you > measured SPDK's vhost-user-blk? I had lot of measuments of vhost-user-blk vs vhost-user-nvme. vhost-user-nvme was always a bit faster but only a bit. Thus I don't think it makes sense to benchamrk against vhost-user-blk. Best regards, Maxim Levitsky