From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bifrost.lang.hm (lang.hm [66.167.227.134]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 79AD53B260 for ; Mon, 6 Jun 2016 18:51:55 -0400 (EDT) Received: from asgard.lang.hm (asgard.lang.hm [10.0.0.100]) by bifrost.lang.hm (8.13.4/8.13.4/Debian-3) with ESMTP id u56MppVf030033; Mon, 6 Jun 2016 15:51:51 -0700 Date: Mon, 6 Jun 2016 15:51:51 -0700 (PDT) From: David Lang X-X-Sender: dlang@asgard.lang.hm To: Benjamin Cronce cc: Dave Taht , cake@lists.bufferbloat.net In-Reply-To: Message-ID: References: User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII Subject: Re: [Cake] faster scheduling, maybe X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 06 Jun 2016 22:51:55 -0000 That works as long as the right answer is to evenly share the bandwidth between the VMs. But what if one VM is running a single elephant flow while another VM is a VoIP server with hundreds of connections? Is it still correct to split the bandwidth evenly between the two? David Lang On Mon, 6 Jun 2016, Benjamin Cronce wrote: > Preliminary benchmarks of new network APIs like netmap are showing 20mpps > between guest and host for untrusted guests and 70mpps to trusted guests, > and scales near linearly with more cores. With that many pps per guest, why > not let the host do an AQM? High end service NICs support multiple virtual > devices where you can tell the NIC to evenly distribute bandwidth among the > virtual devices. It's already mostly a solved problem, just some people > reinventing the wheel. I know FreeBSD is currently looking at adding netmap > to connect the guest to the host so the guests can do line-rate 10Gb and > almost 40Gb. > > On Mon, Jun 6, 2016 at 1:48 PM, David Lang wrote: > >> On Mon, 6 Jun 2016, Dave Taht wrote: >> >> http://info.iet.unipi.it/~luigi/papers/20160511-mysched-preprint.pdf >>> >> >> I don't think so. >> >> They don't even try for fairness between flows, they are just looking at >> fairness between different VMs. they tell a VM that it has complete access >> to the NIC for a time, then give another VM complete access to the NIC. At >> best they put each VMs traffic into a different hardware queue in the NIC. >> >> This avoids all AQM decisions on the part of the host OS, because the >> packets never get to the host OS. >> >> The speed improvement is by bypassing the host OS and just having the VMs >> deliver packets directly to the NIC. This speeds things up, but at the cost >> of any coordination across VMs. Each VM can run fq_codel but it's much >> corser timeslicing between VMs. >> >> David Lang >> >> _______________________________________________ >> Cake mailing list >> Cake@lists.bufferbloat.net >> https://lists.bufferbloat.net/listinfo/cake >> >