> -----Original Message----- > From: snabb-de...@googlegroups.com [mailto:snabb- > de...@googlegroups.com] On Behalf Of Maxime Leroy > Sent: Thursday, July 9, 2015 6:01 AM > To: Michael S. Tsirkin > Cc: Ouyang, Changchun; snabb-de...@googlegroups.com; Marcel > Apfelbaum; qemu-devel@nongnu.org; Nikolay Nikolaev; Luke Gorrie; Long, > Thomas; rk...@redhat.com > Subject: [snabb-devel] Re: [Qemu-devel] [PATCH v5] vhost-user: add multi > queue support > > Hi Michael, > > On Wed, Jul 8, 2015 at 4:29 PM, Michael S. Tsirkin <m...@redhat.com> wrote: > > On Thu, May 28, 2015 at 09:23:06AM +0800, Ouyang Changchun wrote: > >> Based on patch by Nikolay Nikolaev: > >> Vhost-user will implement the multi queue support in a similar way to > >> what vhost already has - a separate thread for each queue. > >> To enable the multi queue functionality - a new command line > >> parameter "queues" is introduced for the vhost-user netdev. > >> > >> Signed-off-by: Nikolay Nikolaev <n.nikol...@virtualopensystems.com> > >> Signed-off-by: Changchun Ouyang <changchun.ouy...@intel.com> > > > > So testing turned up a significant issue with the protocol extension > > in this one. Specifically, remote has no idea how many queues guest > > actually wants to use (it's dynamic, guest changes this at any time). > > We need support for enabling and disabling queues dynamically.
Do you mean we need control queue to negotiate the actual queue number between Guest and host? Or something like that > > > > Given we are past hard freeze, and given no one uses this yet (dpdk > > upstream did not merge supporting protocol), I think the best thing to > > do is to disable this functionality for 2.4. > > I will send a patch to do this shortly. > > You are making a wrong statement, we already use multiqueue for vhost- > user and we expected to have this support officially integrated in qemu 2.4. > > Libvirt 1.2.17 has been released with multiqueue support for vhost-user. > (http://libvirt.org/git/?p=libvirt.git;a=commit;h=366c22f2bcf1ddb8253c123f93 > fd18d1ba9eacd6) > It checks against the version of qemu (i.e. 2.4) to know if multiqueue is > supported or not by qemu. > (http://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=7971723b985b9adc27122a > 3503e7ab38ced2b57f;hp=e7f5510ef2d28ca0ae0ed5751b1fd3018130d6c1) > > Dynamically enabling/disabling queue between host/guest is a nice feature > to have. > But it's not mandatory. You can still configure manually guest and host to use > the same number of queues. Same number of queues on host and guest can work normally, I have validated it with dpdk. > Maybe we could consider still having this in 2.4, And have an enhancement patch set to implement dynamically enabling/disabling in 2.5 or 2.4.x After extending the vhost-user spec. Thanks Changchun
