mbox

[v2,0/5] vhost: support async dequeue data path

Message ID 20220411100032.114434-1-xuan.ding@intel.com (mailing list archive)
Headers

Message

Ding, Xuan April 11, 2022, 10 a.m. UTC 
  From: Xuan Ding <xuan.ding@intel.com>

The presence of asynchronous path allows applications to offload memory
copies to DMA engine, so as to save CPU cycles and improve the copy
performance. This patch set implements vhost async dequeue data path
for split ring. The code is based on latest enqueue changes [1].

This patch set is a new design and implementation of [2]. Since dmadev
was introduced in DPDK 21.11, to simplify application logics, this patch
integrates dmadev in vhost. With dmadev integrated, vhost supports M:N
mapping between vrings and DMA virtual channels. Specifically, one vring
can use multiple different DMA channels and one DMA channel can be
shared by multiple vrings at the same time.

A new asynchronous dequeue function is introduced:
        1) rte_vhost_async_try_dequeue_burst(int vid, uint16_t queue_id,
                struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts,
                uint16_t count, int *nr_inflight,
                uint16_t dma_id, uint16_t vchan_id)

        Receive packets from the guest and offloads copies to DMA
virtual channel.

[1] https://mails.dpdk.org/archives/dev/2022-February/234555.html
[2] https://mails.dpdk.org/archives/dev/2021-September/218591.html

v1->v2:
* fix a typo
* fix a bug in desc_to_mbuf filling

RFC v3 -> v1:
* add sync and async path descriptor to mbuf refactoring
* add API description in docs

RFC v2 -> RFC v3:
* rebase to latest DPDK version

RFC v1 -> RFC v2:
* fix one bug in example
* rename vchan to vchan_id
* check if dma_id and vchan_id valid
* rework all the logs to new standard

Xuan Ding (5):
  vhost: prepare sync for descriptor to mbuf refactoring
  vhost: prepare async for descriptor to mbuf refactoring
  vhost: merge sync and async descriptor to mbuf filling
  vhost: support async dequeue for split ring
  examples/vhost: support async dequeue data path

 doc/guides/prog_guide/vhost_lib.rst    |   7 +
 doc/guides/rel_notes/release_22_07.rst |   4 +
 doc/guides/sample_app_ug/vhost.rst     |   9 +-
 examples/vhost/main.c                  | 292 +++++++++++-----
 examples/vhost/main.h                  |  35 +-
 examples/vhost/virtio_net.c            |  16 +-
 lib/vhost/rte_vhost_async.h            |  33 ++
 lib/vhost/version.map                  |   3 +
 lib/vhost/vhost.h                      |   1 +
 lib/vhost/virtio_net.c                 | 460 ++++++++++++++++++++++---
 10 files changed, 712 insertions(+), 148 deletions(-)