On Fri, Nov 02, 2018 at 10:07:40AM +0100, Jens Freimann wrote: > This is a basic implementation of packed virtqueues as specified in the > Virtio 1.1 draft. A compiled version of the current draft is available > at https://github.com/oasis-tcs/virtio-docs.git (or as .pdf at > https://github.com/oasis-tcs/virtio-docs/blob/master/virtio-v1.1-packed-wd10.pdf > > A packed virtqueue is different from a split virtqueue in that it > consists of only a single descriptor ring that replaces available and > used ring, index and descriptor pointers. > > Each descriptor is readable and writable and has a flags field. These flags > will mark if a descriptor is available or used. To detect new available > descriptors > even after the ring has wrapped, device and driver each have a > single-bit wrap counter that is flipped from 0 to 1 and vice versa every time > the last descriptor in the ring is used/made available.
Do you have the performance numbers which can show the performance improvements in driver and vhost? Thanks > > v9-v10: > * don't mix index into buffer list and descriptors > * whitespace and formatting issues > * remove "VQ:" in dump virtqueue patch > * add extra packed vring struct to virtqueue and change function > prototypes and code accordingly > * move wrap_counters to virtqueue > * make if-conditions for packed and !packed more clear in > set_rxtx_funcs() > * initialize wrap counters in first patch, instead of rx and tx > implementation patch > * make virtio-user not supported with packed virtqueues, to > be fixed in other patch set? > > v8-v9: > * fix virtio_ring_free_chain_packed() to handle descriptors > correctly in case of out-of-order > * fix check in virtqueue_xmit_cleanup_packed() to improve performance > > v7->v8: > * move desc_is_used change to correct patch > * remove trailing newline > * correct xmit code, flags update and memory barrier > * move packed desc init to dedicated function, split > and packed variant > > > Jens Freimann (9): > net/virtio: vring init for packed queues > net/virtio: add packed virtqueue defines > net/virtio: add packed virtqueue helpers > net/virtio: dump packed virtqueue data > net/virtio: implement transmit path for packed queues > net/virtio: implement receive path for packed queues > net/virtio: add virtio send command packed queue support > net/virtio: enable packed virtqueues by default > net/virtio-user: disable packed virtqueues when CTRL_VQ enabled > > drivers/net/virtio/virtio_ethdev.c | 202 +++++-- > drivers/net/virtio/virtio_ethdev.h | 5 + > drivers/net/virtio/virtio_pci.h | 7 + > drivers/net/virtio/virtio_ring.h | 64 +- > drivers/net/virtio/virtio_rxtx.c | 561 +++++++++++++++++- > .../net/virtio/virtio_user/virtio_user_dev.c | 1 + > drivers/net/virtio/virtqueue.c | 22 + > drivers/net/virtio/virtqueue.h | 69 ++- > 8 files changed, 859 insertions(+), 72 deletions(-) > > -- > 2.17.1 >
