From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: Unable to create more than 1 guest virtio-net device using vhost-net backend Date: Mon, 22 Mar 2010 20:16:23 +0200 Message-ID: <20100322181623.GA20188@redhat.com> References: <1269037167.5127.12.camel@w-sridhar.beaverton.ibm.com> <20100321095544.GA6443@redhat.com> <4BA5F0D5.6020801@redhat.com> <20100321101527.GH6443@redhat.com> <4BA5F50B.8080302@redhat.com> <20100321113443.GB12339@redhat.com> <4BA609E5.40504@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Sridhar Samudrala , netdev , "kvm@vger.kernel.org" , gleb@redhat.com To: Avi Kivity Return-path: Content-Disposition: inline In-Reply-To: <4BA609E5.40504@redhat.com> Sender: kvm-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Sun, Mar 21, 2010 at 01:58:29PM +0200, Avi Kivity wrote: > On 03/21/2010 01:34 PM, Michael S. Tsirkin wrote: >> On Sun, Mar 21, 2010 at 12:29:31PM +0200, Avi Kivity wrote: >> >>> On 03/21/2010 12:15 PM, Michael S. Tsirkin wrote: >>> >>>>>> Nothing easy that I can see. Each device needs 2 of these. Avi, Gleb, >>>>>> any objections to increasing the limit to say 16? That would give us >>>>>> 5 more devices to the limit of 6 per guest. >>>>>> >>>>>> >>>>>> >>>>> Increase it to 200, then. >>>>> >>>>> >>>> OK. I think we'll also need a smarter allocator >>>> than bus->dev_count++ than we now have. Right? >>>> >>>> >>> No, why? >>> >> We'll run into problems if devices are created/removed in random order, >> won't we? >> > > unregister_dev() takes care of it. > >>> Eventually we'll want faster scanning than the linear search we employ >>> now, though. >>> >> Yes I suspect with 200 entries we will :). Let's just make it 16 for >> now? >> > > Let's make it 200 and fix the performance problems later. Making it 16 > is just asking for trouble. I did this and performance with vhost seems to become much more noisy, and drop by about 10% on average, even though in practice only a single device is created. Still trying to figure it out ... Any idea? > -- > error compiling committee.c: too many arguments to function