On 12/17/18 10:31 PM, 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. With this patch set I see performance equal or slightly better (+2-3%) in a PVP scenario compared to split virtqueues (v18.11 in host) regards, Jens v13->v14: * replace (_)set_desc_avail() * remove unrelated changes in split vq code * remove trailing line * remove RING_EVENT_IDX code from virtqueue_enable_intr_packed() * set interrupt disable flag unconditionally * change error message for disabled control virtqueues v12->v13: * re-order patches 1-3 to address Maximes comment. Move all defines and data structures to patch one, all helpers to patch 2. * build-tested and ran checkpatch on all patches again * add split/packed versions for virtio_enable_intr() * remove redundant changes from split vq code * just return -1 when cq is enabled for packed vqs in virtio-user v11->v12: * add a patch to disable control vq when packed vq is enabled. I have a patch to support this but it needs a bit more work and I think it shouldn't stop this series from being applied * rework mergeable receive buffer code to be more efficient, by batching descriptor refill, similar to what Maxime proposed for split virtqueues * removed unnecessary checks in virtio_recv_mergeable_pkts_packed (Maxime) * Did not merge receive functions as Maxime suggested because it seemed to cause a small performance regression * Move event_flags_shadow from patch 3 to 1 (Maxime) * Did not merge xmit functions and call _split/_packed functions from there because it seemed to cause small performance drop (-0.5%) (Maxime) v10-v11: * this version includes some fixes from Tiwei, so I added his Signed-off-by to some of the patches * fix hang with mergable rx buffers (Tiwei) * clean-up code and simplify buffer handling (Tiwei) * rebase to current virtio-next master branch 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: add packed virtqueue defines net/virtio: add packed virtqueue helpers net/virtio: vring init for packed queues 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-user: fail if cq used with packed vq net/virtio: enable packed virtqueues by default Yuanhan Liu (1): net/virtio-user: add option to use packed queues drivers/net/virtio/virtio_ethdev.c | 228 +++++-- drivers/net/virtio/virtio_ethdev.h | 8 + drivers/net/virtio/virtio_pci.h | 7 + drivers/net/virtio/virtio_ring.h | 58 +- drivers/net/virtio/virtio_rxtx.c | 611 +++++++++++++++++- .../net/virtio/virtio_user/virtio_user_dev.c | 27 +- .../net/virtio/virtio_user/virtio_user_dev.h | 2 +- drivers/net/virtio/virtio_user_ethdev.c | 14 +- drivers/net/virtio/virtqueue.c | 43 +- drivers/net/virtio/virtqueue.h | 109 +++- 10 files changed, 1044 insertions(+), 63 deletions(-)
Applied to dpdk-next-virtio Thanks, Maxime
