On Wed, Feb 14, 2018 at 10:37:07AM +0800, Jason Wang wrote: > Hi all: > > This RFC implement a subset of packed ring which was described at > https://github.com/oasis-tcs/virtio-docs/blob/master/virtio-v1.1-packed-wd07.pdf > . The code were tested with pmd implement by Jens at > http://dpdk.org/ml/archives/dev/2018-January/089417.html. Minor > change was needed for pmd codes to kick virtqueue since it assumes a > busy polling backend. > > Test were done between localhost and guest. Testpmd (rxonly) in guest > reports 2.4Mpps. Testpmd (txonly) repots about 2.1Mpps.
How does this compare with the split ring design? > It's not a complete implemention, here's what were missed: > > - Device Area > - Driver Area > - Descriptor indirection > - Zerocopy may not be functional > - Migration path is not tested > - Vhost devices except for net > - vIOMMU can not work (mainly because the metadata prefetch is not > implemented). > - See FIXME/TODO in the codes for more details > - No batching or other optimizations were implemented ioeventfd for PIO/mmio/s390. > For a quick prototype, this series open code the tracking of warp > counter and descriptor index at net device. This will be addressed in > the future by: > > - Move get_rx_bufs() from net.c to vhost.c > - Let vhost_get_vq_desc() returns vring_used_elem instad of head id > > With the above, we can hide the internal (at least part of) vring > layout from specific device. > > Please review. > > Thanks > > Jason Wang (2): > virtio: introduce packed ring defines > vhost: packed ring support > > drivers/vhost/net.c | 14 +- > drivers/vhost/vhost.c | 351 > ++++++++++++++++++++++++++++++++++--- > drivers/vhost/vhost.h | 6 +- > include/uapi/linux/virtio_config.h | 9 + > include/uapi/linux/virtio_ring.h | 17 ++ > 5 files changed, 369 insertions(+), 28 deletions(-) > > -- > 2.7.4