On Wed, Aug 9, 2023 at 8:56 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. As this RFC set is to seek early feedback on the uAPI > and driver API part, for now there's no associated driver patch consuming > the API. As soon as the support is in place on both hardware device and > driver, performance data will be show using real hardware device. 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 plan of the intended driver implementation is to use a dedicated > group (specifically, 2 in below table) to host descriptor table for > all 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 a same group (1). I'm fine with this, but I think we need an implementation in the driver (e.g the simulator). Thanks > > > | 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 > > 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
