On Sat, Sep 9, 2023 at 4:45 PM Si-Wei Liu <si-wei.liu@xxxxxxxxxx> wrote: > > Following patchset introduces dedicated group for descriptor table to > reduce live migration downtime when passthrough VQ is being switched > to shadow VQ. This RFC v2 is sent to incorporate the early feedback > from reviewers on the uAPI and driver API part of changes, the > associated driver patch set consuming ths API will come around > soon along with formal submission of this series. > > Some initial performance data will be gathered using the real > hardware device with mlx5_vdpa. The target goal of this series is to > reduce the SVQ switching overhead to less than 300ms on a ~100GB > guest with 2 non-mq vhost-vdpa devices. The reduction in the downtime > is thanks to avoiding the full remap in the switching. > > The plan of the intended driver implementation is to use a dedicated > group (specifically, 2 in below table) to host the descriptor tables > for data vqs, different from where buffer addresses are contained (in > group 0 as below). cvq does not have to allocate dedicated group for > descriptor table, so its buffers and descriptor table would always > belong to the same group (1 in table below). > > > | data vq | ctrl vq > ==============+==========+=========== > vq_group | 0 | 1 > vq_desc_group | 2 | 1 > > > --- > > Si-Wei Liu (3): > vdpa: introduce dedicated descriptor group for virtqueue > vhost-vdpa: introduce descriptor group backend feature > vhost-vdpa: uAPI to get dedicated descriptor group id Looks good to me but I'd expect example implementations in the parent. Thanks > > drivers/vhost/vdpa.c | 27 +++++++++++++++++++++++++++ > include/linux/vdpa.h | 11 +++++++++++ > include/uapi/linux/vhost.h | 8 ++++++++ > include/uapi/linux/vhost_types.h | 5 +++++ > 4 files changed, 51 insertions(+) > > -- > 1.8.3.1 > _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
