[dpdk-dev] [PATCH v4 00/20] implement packed virtqueues
Jens Freimann
jfreimann at redhat.com
Thu Apr 19 09:07:31 CEST 2018
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
It does not implement yet indirect descriptors and checksum offloading.
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.
changes from v3->v4:
* added helpers to increment index and set available/used flags
* driver keeps track of number of descriptors used
* change logic in set_rxtx_funcs()
* add patch for ctrl virtqueue with support for packed virtqueues
* rename virtio-1.1.h to virtio-packed.h
* fix wrong sizeof() in "vhost: vring address setup for packed queues"
* fix coding style of function definition in "net/virtio: add packed
virtqueue helpers"
* fix padding in vring_size()
* move patches to enable packed virtqueues end of series
* v4 has two open problems: I'm sending it out anyway for feedback/help:
* when VIRTIO_NET_F_MRG_RXBUF enabled only 128 packets are send in
guest, i.e. when ring is full for the first time. I suspect a bug in
setting the avail/used flags
changes from v2->v3:
* implement event suppression
* add code do dump packed virtqueues
* don't use assert in vhost code
* rename virtio-user parameter to packed-vq
* support rxvf flush
changes from v1->v2:
* don't use VIRTQ_DESC_F_NEXT in used descriptors (Jason)
* no rte_panice() in guest triggerable code (Maxime)
* use unlikely when checking for vq (Maxime)
* rename everything from _1_1 to _packed (Yuanhan)
* add two more patches to implement mergeable receive buffers
Jens Freimann (16):
net/virtio: vring init for packed queues
net/virtio: add virtio 1.1 defines
net/virtio: add packed virtqueue helpers
net/virtio: flush packed receive virtqueues
net/virtio: dump packed virtqueue data
net/virtio: implement transmit path for packed queues
net/virtio: add virtio send command packed queue support
net/virtio: add support for mergeable buffers with packed virtqueues
net/virtio: add support for event suppression
vhost: add virtio packed virtqueue defines
vhost: add helpers for packed virtqueues
vhost: dequeue for packed queues
vhost: packed queue enqueue path
vhost: add support for mergeable buffers with packed virtqueues
vhost: add event suppression for packed queues
net/virtio: by default disable packed virtqueues
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: by default disable packed virtqueues
config/common_base | 2 +
drivers/net/virtio/virtio_ethdev.c | 127 +++++-
drivers/net/virtio/virtio_ethdev.h | 5 +
drivers/net/virtio/virtio_pci.h | 8 +
drivers/net/virtio/virtio_ring.h | 97 ++++-
drivers/net/virtio/virtio_rxtx.c | 357 +++++++++++++++-
drivers/net/virtio/virtio_user/virtio_user_dev.c | 6 +-
drivers/net/virtio/virtio_user/virtio_user_dev.h | 3 +-
drivers/net/virtio/virtio_user_ethdev.c | 15 +-
drivers/net/virtio/virtqueue.c | 16 +
drivers/net/virtio/virtqueue.h | 113 ++++-
lib/librte_vhost/socket.c | 5 +
lib/librte_vhost/vhost.c | 16 +
lib/librte_vhost/vhost.h | 70 +++-
lib/librte_vhost/vhost_user.c | 45 +-
lib/librte_vhost/virtio-packed.h | 86 ++++
lib/librte_vhost/virtio_net.c | 503 +++++++++++++++++++++--
17 files changed, 1398 insertions(+), 76 deletions(-)
create mode 100644 lib/librte_vhost/virtio-packed.h
--
2.14.3
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