On 06/07/2020 16:30, Stokes, Ian wrote: > > > On 7/2/2020 12:56 PM, Kevin Traynor wrote: >> On 02/07/2020 12:18, Stokes, Ian wrote: >>> >>> >>> On 7/1/2020 3:08 PM, Kevin Traynor wrote: >>>> On 01/07/2020 13:46, Ilya Maximets wrote: >>>>> On 7/1/20 1:46 PM, Kevin Traynor wrote: >>>>>> On 01/07/2020 11:28, Stokes, Ian wrote: >>>>>>> Hi All, >>>>>>> >>>>>>> While completing validation work for DPDK 18.11.9 and 19.11.3 it was >>>>>>> found that zero-copy for vhostuserclient devices is no longer possible. >>>>>>> Please see commit below from 18.11.9 (note this patch is also in DPDK >>>>>>> 19.11.3) >>>>>>> >>>>>> >>>>>> Thanks catching this in your validation, it almost certainly wouldn't >>>>>> have been caught otherwise. >>>>> >>>>> Definitely a good catch. Thanks. >>>>> >>>>>> >>>>>>> >>>>>>> commit 81e025d7ed6a802845909df6fb90505508dc0fbf >>>>>>> Author: Xuan Ding <[email protected]> >>>>>>> Date: Wed Apr 29 02:59:46 2020 +0000 >>>>>>> >>>>>>> vhost: prevent zero-copy with incompatible client mode >>>>>>> >>>>>>> [ upstream commit 715070ea10e6da1169deef2a3ea77ae934b4c333 ] >>>>>>> >>>>>>> In server mode, virtio-user inits under the assumption that >>>>>>> vhost-user >>>>>>> supports a list of features. However, this could be problematic >>>>>>> when >>>>>>> in_order feature is negotiated but not supported by vhost-user >>>>>>> when >>>>>>> enables dequeue_zero_copy later. >>>>>>> >>>>>>> Add handling when vhost-user enables dequeue_zero_copy as client. >>>>> >>>>> IIUC, this patch basically drops the feature for perfectly fine cases >>>>> with VMs. While it was intended to forbid running zero-copy with >>>>> virtio-user >>>>> it breaks a different usecase blocking the feature entirely. >>>>> >>>>> Isn't it an API breakage? IMHO, it should not have been backported in the >>>>> first place, since dropping the feature is not what usually expected in >>>>> stable releases. And this must be in release notes anyway. >>>>> >>>>> I think, the right solution here should be to make a patch to handle >>>>> specific >>>>> virtio-user case and stop blocking valid cases and release new DPDK stable >>>>> versions for already released ones. >>>>> >>>>> If it's too hard to make a patch or no-one wants to work on this, just >>>>> revert >>>>> these changes from stable branches and release a new stable DPDK version >>>>> for both 18.11 and 19.11. But anyway, regression should be addressed in >>>>> DPDK >>>>> before 20.11 or it will block OVS upgrade to that version. >>>>> >>>> >>>> It is not in a released 18.11. It was caught by Ian's team as part of >>>> 18.11.9-rc testing. >>>> >>> >>> OK so it seems like we can use 18.11.9 for the 2.11 and 2.13 branches as >>> it will have this patch reverted. >>> >>> Is there an 18.11.9 RC3 planned? We can test it if it's of use. >>> >> >> I've just pushed it to the 18:11 branch, can you test with that? >> >> I wasn't planning on an rc3 at this stage for just this patch, but if >> you need a tarball for testing automation or something, let me know and >> I can create it. > > Thanks Kevin, > > the team tested on our side and see the expected behavior now. Looks > good to go. >
Thanks Ian. I should be able to make the release in the next few days, once a couple of other open items are closed. > Regards > Ian > _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
