Thanks for the confirmation, glad I reached the person who knows the nuts and bolts of virtio :-). So if the host is not in our control (ie if I am just running as a VM on host provided by thirdparty vendor), is there any workaround I can do from the guest side to prevent problems from happening on a guest restart ?
And if theres no workarounds at all and the host has to change, instead of asking the third party vendor to do a wholesale upgrade to 16.04, is there one/few commits that can be added to the host ovs-dpdk to take care of this guest restart virtio-reset-before opening case ? Rgds, Gopa. On Thu, Mar 16, 2017 at 10:24 PM, Yuanhan Liu <yuanhan....@linux.intel.com> wrote: > On Thu, Mar 16, 2017 at 10:20:30PM -0700, Gopakumar Choorakkot Edakkunni > wrote: > > >> When I was saying dpdk version, I meant the DPDK version with OVS. > > > > Oh I see! My apologies for the misuderstanding. The dpdk version used by > host > > ovs should be dpdk2.2, the guest process uses dpdk16.07. The OVS process > is not > > getting restarted, what is getting restarted is the guest process using > > dpdk16.07 - so the above clarifications you had about virtio being > > reset-before-opened on guest restart - does that still hold good or does > that > > need the HOST side dpdk to be 16.04 or above ? > > Yes, the HOST dpdk should be >= v16.04. > > --yliu > > > > >> And yes, the fixes are not included in the DPDK required for OVS 2.4. > > > > Thanks for the info. > > > > Rgds, > > Gopa. > > > > On Thu, Mar 16, 2017 at 10:13 PM, Yuanhan Liu < > yuanhan....@linux.intel.com> > > wrote: > > > > On Thu, Mar 16, 2017 at 09:56:01PM -0700, Gopakumar Choorakkot > Edakkunni > > wrote: > > > Hi Yuanhan, > > > > > > Thanks for the confirmation about not having to do anything > special to > > close > > > the ports on dpdk going down or coming up. > > > > > > As for the question about if I met any issue of ovs getting stuck > - yes, > > my > > > guest process runs dpdk 16.07 as I mentioned earlier - and if I > kill my > > guest > > > process, then the host OVS-dpdk on the host reports stall ! The > OVS-dpdk > > and > > > emu versions I use are as below. But maybe that is because of the > ovs > > missing > > > the fixes you mentioned ? > > > > When I was saying dpdk version, I meant the DPDK version with OVS. > > > > > ~# ovs-vswitchd --version > > > ovs-vswitchd (Open vSwitch) 2.4.1 > > > > And yes, the fixes are not included in the DPDK required for OVS 2.4. > > > > --yliu > > > > > Compiled Nov 14 2016 06:53:31 > > > # kvm --version > > > QEMU emulator version 2.2.0, Copyright (c) 2003-2008 Fabrice > Bellard > > > ~# > > > > > > > > > Rgds, > > > Gopa. > > > > > > On Thu, Mar 16, 2017 at 9:35 PM, Yuanhan Liu < > yuanhan....@linux.intel.com > > > > > > wrote: > > > > > > On Thu, Mar 16, 2017 at 07:48:28PM -0700, Gopakumar Choorakkot > > Edakkunni > > > wrote: > > > > Thanks a lot for the response Yuanhan. I am using dpdk > v16.07. So > > what > > > you are > > > > saying is that in 16.07, we dont really need to call > > rte_eth_dev_close() > > > on > > > > exit, > > > > > > It's not about "don't really need", it's more like "it's hard > to". > > Just > > > think that it may crash at any time. > > > > > > > because dpdk will ensure that it will do virtio reset before > init > > when it > > > > comes up right ? > > > > > > No, It just handles the abnormal case well when guest APP > restarts. > > > > > > > Regarding the vhost commits you mentioned - do we still need > those > > fixes > > > if we > > > > have the "virtio reset before init" mechanism ? > > > > > > Yes, we still need them: just think some malicious guest may > also > > forge > > > data like that. > > > > > > I'm a bit confused then. Have you actually met any issue (like > got > > stucked) > > > with DPDK v16.07? > > > > > > --yliu > > > > > > > Or that is a seperate problem > > > > altogether (and hence we would need those fixes) ? > > > > > > > > Rgds, > > > > Gopa. > > > > > > > > On Thu, Mar 16, 2017 at 7:06 PM, Yuanhan Liu < > > yuanhan....@linux.intel.com > > > > > > > > wrote: > > > > > > > > On Thu, Mar 16, 2017 at 12:39:16PM -0700, Gopakumar > Choorakkot > > > Edakkunni > > > > wrote: > > > > > So the doc says we should call rte_eth_dev_close() > *before* > > going > > > down. > > > > And I > > > > > know that especially in dpdk-virtionet in the guest + > > ovs-dpdk in > > > the > > > > host, > > > > > the ovs ends up getting stalled/stuck (!!) if I dont > close > > the port > > > > before > > > > > starting() it when the guest dpdk process comes back > up. > > > > > > > > I'm assuming you were using an old version, something > like dpdk > > v2.2? > > > > IIRC, DPDK v16.04 should have fixed your issue. > > > > > > > > > Considering that this not done properly can screw up > the HOST > > ovs, > > > and I > > > > want > > > > > to do everything possible to avoid that, I want to be > 200% > > sure > > > that I > > > > call > > > > > close even if my process gets a kill -9 .. So > obviously the > > only > > > way of > > > > doing > > > > > that is to close the port when the dpdk process comes > back up > > and > > > > *before* we > > > > > init the port. rte_eth_dev_close() is not capable of > doing > > that as > > > it > > > > expects > > > > > the port parameters to be initialized etc.. before it > can be > > > called. > > > > > > > > We do virtio reset before init, which is basically what > > > rte_eth_dev_close() > > > > mainly does. So I see no big issue here. > > > > > > > > The stuck issue is due to hugepage reset by the guest > DPDK > > > application, > > > > leading all virtio vring elements being mem zeroed. The > old > > vhost > > > doesn't > > > > handle it well, as a result, it got stuck. And here are > some > > relevant > > > > commits: > > > > > > > > a436f53 vhost: avoid dead loop chain > > > > c687b0b vhost: check for ring descriptors overflow > > > > 623bc47 vhost: do sanity check for ring descriptor > length > > > > > > > > --yliu > > > > > > > > > Any other > > > > > suggestions on what can be done to close on restart > rather > > than > > > close on > > > > going > > > > > down ? Thought of bouncing this by the alias before I > add a > > version > > > of > > > > close > > > > > myself that can do this close-on-restart > > > > > > > > > > > > > > > > > > >
