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-wd07.pdf
It does not implement yet indirect descriptors and checksum offloading. VIRTIO_F_IN_ORER is not implemented, as well as support for mergeable buffers with packed queues. Patches for this will follow soon. 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 buffer. 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. The idea behind this is to 1. improve performance by avoiding cache misses and 2. be easier for devices to implement. Regarding performance: with these patches I get 21.13 Mpps on my system as compared to 18.8 Mpps with the virtio 1.0 code. Packet size was 64 bytes, 0.05% acceptable loss. Test setup is described as in http://dpdk.org/doc/guides/howto/pvp_reference_benchmark.html Packet generator: MoonGen Intel(R) Xeon(R) CPU E5-2665 0 @ 2.40GHz Intel X710 NIC RHEL 7.4 Device under test: Intel(R) Xeon(R) CPU E5-2667 v4 @ 3.20GHz Intel X710 NIC RHEL 7.4 VM on DuT: RHEL7.4 I plan to do more performance test with bigger frame sizes. This patch series is based on a prototype implemented by Yuanhan Liu and Tiwei Bie. regards, Jens Freimann (10): net/virtio: vring init for packed queues net/virtio: don't call virtio_disable_intr() for packed queues net/virtio: add virtio 1.1 defines net/virtio: add packed virtqueue helpers net/virtio: don't dump split virtqueue data net/virtio: implement transmit path for packed queues vhost: add virtio 1.1 defines vhost: add helpers for packed virtqueues vhost: dequeue for packed queues vhost: packed queue enqueue path Yuanhan Liu (4): net/virtio-user: add option to use packed queues net/virtio: implement receive path for packed queues vhost: vring address setup for packed queues vhost: enable packed virtqueues drivers/net/virtio/Makefile | 1 + drivers/net/virtio/virtio_ethdev.c | 50 ++-- drivers/net/virtio/virtio_ethdev.h | 5 + drivers/net/virtio/virtio_pci.h | 8 + drivers/net/virtio/virtio_ring.h | 63 ++++- drivers/net/virtio/virtio_rxtx.c | 141 +++++++++- drivers/net/virtio/virtio_rxtx_1.1.c | 161 ++++++++++++ drivers/net/virtio/virtio_user/virtio_user_dev.c | 12 +- drivers/net/virtio/virtio_user/virtio_user_dev.h | 3 +- drivers/net/virtio/virtio_user_ethdev.c | 15 +- drivers/net/virtio/virtqueue.c | 3 + drivers/net/virtio/virtqueue.h | 14 +- lib/librte_vhost/vhost.c | 5 + lib/librte_vhost/vhost.h | 7 +- lib/librte_vhost/vhost_user.c | 17 +- lib/librte_vhost/virtio-1.1.h | 63 +++++ lib/librte_vhost/virtio_net.c | 321 ++++++++++++++++++++++- 17 files changed, 859 insertions(+), 30 deletions(-) create mode 100644 drivers/net/virtio/virtio_rxtx_1.1.c create mode 100644 lib/librte_vhost/virtio-1.1.h -- 2.14.3