Re: [PATCH v9 0/8] implement packed virtqueues

[Tiwei Bie <tiwei.bie@intel.com>]

On Wed, Oct 24, 2018 at 04:32:28PM +0200, 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.

Do we have the performance numbers which can show the
performance improvements in driver and vhost?

Thanks

> 
> 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 (8):
>   net/virtio: vring init for packed queues
>   net/virtio: add packed virtqueue defines
>   net/virtio: add packed virtqueue helpers
>   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: enable packed virtqueues by default
> 
>  drivers/net/virtio/virtio_ethdev.c | 154 ++++++--
>  drivers/net/virtio/virtio_ethdev.h |   5 +
>  drivers/net/virtio/virtio_pci.h    |   7 +
>  drivers/net/virtio/virtio_ring.h   | 105 +++++-
>  drivers/net/virtio/virtio_rxtx.c   | 560 +++++++++++++++++++++++++++--
>  drivers/net/virtio/virtqueue.c     |  22 ++
>  drivers/net/virtio/virtqueue.h     |  42 ++-
>  7 files changed, 841 insertions(+), 54 deletions(-)
> 
> -- 
> 2.17.1
>