From owner-freebsd-net@freebsd.org Thu Oct 26 14:31:42 2017 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 6B210E4B13A for ; Thu, 26 Oct 2017 14:31:42 +0000 (UTC) (envelope-from aspam@cox.net) Received: from fed1rmfepi208.cox.net (fed1rmfepi208.cox.net [68.230.241.153]) by mx1.freebsd.org (Postfix) with ESMTP id 4667D80389 for ; Thu, 26 Oct 2017 14:31:42 +0000 (UTC) (envelope-from aspam@cox.net) Received: from eastrmimpo210.cox.net ([68.230.241.225]) by eastrmfepo102.cox.net (InterMail vM.8.01.05.28 201-2260-151-171-20160122) with ESMTP id <20171026143124.NGUX14605.eastrmfepo102.cox.net@eastrmimpo210.cox.net> for ; Thu, 26 Oct 2017 10:31:24 -0400 Received: from thunder.sweets ([68.100.138.62]) by eastrmimpo210.cox.net with cox id SEXQ1w0051LxgH801EXQ9X; Thu, 26 Oct 2017 10:31:24 -0400 X-CT-Class: Clean X-CT-Score: 0.00 X-CT-RefID: str=0001.0A020206.59F1F1BC.00E6, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0 X-CT-Spam: 0 X-Authority-Analysis: v=2.2 cv=c+jbeV1l c=1 sm=1 tr=0 a=3mkzfl4ircflX6G+lDqBYw==:117 a=3mkzfl4ircflX6G+lDqBYw==:17 a=IkcTkHD0fZMA:10 a=x7bEGLp0ZPQA:10 a=02M-m0pO-4AA:10 a=e9ASbk4n0QUA:10 a=HxoghPbS-FUynUJKAIkA:9 a=QEXdDO2ut3YA:10 X-CM-Score: 0.00 Authentication-Results: cox.net; none Received: from [10.10.10.15] (thunder.sweets [10.10.10.15]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by thunder.sweets (Postfix) with ESMTP id CC031113FC; Thu, 26 Oct 2017 10:31:23 -0400 (EDT) Message-ID: <59F1F1BA.3020608@cox.net> Date: Thu, 26 Oct 2017 10:31:22 -0400 From: Joe Buehler User-Agent: Thunderbird 1.5.0.12 (X11/20120201) MIME-Version: 1.0 To: Vincenzo Maffione CC: "freebsd-net@freebsd.org" Subject: Re: virtio_net / netmap RX dropping frames References: <59F0FBEE.6030008@cox.net> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 26 Oct 2017 14:31:42 -0000 Vincenzo Maffione wrote: > I guess you are using a FreeBSD guest. Is this the case? If you have the Sorry, I am using LINUX, ubuntu 16.04 LTS for both host and VM. I am posting here at standing request of netmap driver author. The host has 24 CPUs @ 2.5 GHz and 128G of memory and is *idle* so I am a bit disappointed > chance, try a linux guest to check if virtio-net works better there > (I've used netmap on the netmap-patched virtio-net in Linux guests, > never tried on FreeBSD). > The netmap ring size is just the NIC ring size. If you change the > virtio-net NIC ring size (sysctl on FreeBSD, I guess). OK I'll look into that. I increased the ring size on the host ixgbe but that had no effect so I guess it must be virtio_net. > Anyway, for your specific use-case (VM accessing the physical 10G NIC) > there is a way better solution, which is the netmap passthrough. Unfortunately I don't have control of the host, just the VM, so pt netmap is not an option. My initial query regarded frame drops but the latency is also pretty bad. The LINUX ping utility inside the VM says 0.2 mS consistently without netmap in use. My app sees that value for almost all frames but it spikes (up to 0.6 mS!) for a few frames, which is not acceptable for this application -- was expecting much better due to network stack bypass. And this is just 100 frames/sec... Joe Buehler