Hello all:

This sereis tries to implement the VIRTIO_F_IN_ORDER to
virtio_ring. This is done by introducing virtqueue ops so we can
implement separate helpers for different virtqueue layout/features
then the in-order were implemented on top.

Tests shows 2%-19% imporvment with packed virtqueue PPS with KVM guest
vhost-net/testpmd on the host.

Changes since V8:

- Rebase to vhost.git linux-next branch
- Fix issue when indirect descriptor is disabled
- use UINT_MAX instead of vq->num to indicate no batching is pending
- Tweak the comments for used_entry
- Various coding style tweaks and typo fixes
- Try to use in_order varianet in in_order ops

Changes since v7:

- Rebase on vhost.git linux-next branch
- Tweak the comment to explain the usage of free_head

Changes since V6:

- Rebase on vhost.git linux-next branch
- Fix poking packed virtqueue in more_used_split_in_order()
- Fix calling detach_buf_packed_in_order() unconditonally in
  virtqueue_detach_unused_buf_packed()
- Typo and indentation fixes
- Fix wrong changelog of patch 7

Changes since V5:

- rebase on vhost.git linux-next branch
- reorder the total_len to reduce memory comsuming

Changes since V4:

- Fix build error when DEBUG is enabled
- Fix function duplications
- Remove unnecessary new lines

Changes since V3:

- Re-benchmark with the recent vhost-net in order support
- Rename the batched used id and length
- Other minor tweaks

Changes since V2:

- Fix build warning when DEBUG is enabled

Changes since V1:

- use const global array of function pointers to avoid indirect
  branches to eliminate retpoline when mitigation is enabled
- fix used length calculation when processing used ids in a batch
- fix sparse warnings

Jason Wang (19):
  virtio_ring: rename virtqueue_reinit_xxx to virtqueue_reset_xxx()
  virtio_ring: switch to use vring_virtqueue in virtqueue_poll variants
  virtio_ring: unify logic of virtqueue_poll() and more_used()
  virtio_ring: switch to use vring_virtqueue for virtqueue resize
    variants
  virtio_ring: switch to use vring_virtqueue for virtqueue_kick_prepare
    variants
  virtio_ring: switch to use vring_virtqueue for virtqueue_add variants
  virtio: switch to use vring_virtqueue for virtqueue_get variants
  virtio_ring: switch to use vring_virtqueue for enable_cb_prepare
    variants
  virtio_ring: use vring_virtqueue for enable_cb_delayed variants
  virtio_ring: switch to use vring_virtqueue for disable_cb variants
  virtio_ring: switch to use vring_virtqueue for detach_unused_buf
    variants
  virtio_ring: switch to use unsigned int for virtqueue_poll_packed()
  virtio_ring: introduce virtqueue ops
  virtio_ring: determine descriptor flags at one time
  virtio_ring: factor out core logic of buffer detaching
  virtio_ring: factor out core logic for updating last_used_idx
  virtio_ring: factor out split indirect detaching logic
  virtio_ring: factor out split detaching logic
  virtio_ring: add in order support

 drivers/virtio/virtio_ring.c | 930 +++++++++++++++++++++++++++--------
 1 file changed, 716 insertions(+), 214 deletions(-)

-- 
2.31.1

On Tue, Nov 25, 2025 at 3:08 PM Jason Wang <jasowang@redhat.com> wrote:
>
> Hello all:
>
> This sereis tries to implement the VIRTIO_F_IN_ORDER to
> virtio_ring. This is done by introducing virtqueue ops so we can
> implement separate helpers for different virtqueue layout/features
> then the in-order were implemented on top.
>
> Tests shows 2%-19% imporvment with packed virtqueue PPS with KVM guest
> vhost-net/testpmd on the host.
>
> Changes since V8:
>
> - Rebase to vhost.git linux-next branch
> - Fix issue when indirect descriptor is disabled
> - use UINT_MAX instead of vq->num to indicate no batching is pending
> - Tweak the comments for used_entry
> - Various coding style tweaks and typo fixes
> - Try to use in_order varianet in in_order ops

Michael, any chance to make this for this merge window?

Thanks

On Tue, Dec 23, 2025 at 09:18:47AM +0800, Jason Wang wrote:
> On Tue, Nov 25, 2025 at 3:08 PM Jason Wang <jasowang@redhat.com> wrote:
> >
> > Hello all:
> >
> > This sereis tries to implement the VIRTIO_F_IN_ORDER to
> > virtio_ring. This is done by introducing virtqueue ops so we can
> > implement separate helpers for different virtqueue layout/features
> > then the in-order were implemented on top.
> >
> > Tests shows 2%-19% imporvment with packed virtqueue PPS with KVM guest
> > vhost-net/testpmd on the host.
> >
> > Changes since V8:
> >
> > - Rebase to vhost.git linux-next branch
> > - Fix issue when indirect descriptor is disabled
> > - use UINT_MAX instead of vq->num to indicate no batching is pending
> > - Tweak the comments for used_entry
> > - Various coding style tweaks and typo fixes
> > - Try to use in_order varianet in in_order ops
> 
> Michael, any chance to make this for this merge window?
> 
> Thanks

want to fix last minor comments?

On Tue, Dec 23, 2025 at 9:29 AM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Tue, Dec 23, 2025 at 09:18:47AM +0800, Jason Wang wrote:
> > On Tue, Nov 25, 2025 at 3:08 PM Jason Wang <jasowang@redhat.com> wrote:
> > >
> > > Hello all:
> > >
> > > This sereis tries to implement the VIRTIO_F_IN_ORDER to
> > > virtio_ring. This is done by introducing virtqueue ops so we can
> > > implement separate helpers for different virtqueue layout/features
> > > then the in-order were implemented on top.
> > >
> > > Tests shows 2%-19% imporvment with packed virtqueue PPS with KVM guest
> > > vhost-net/testpmd on the host.
> > >
> > > Changes since V8:
> > >
> > > - Rebase to vhost.git linux-next branch
> > > - Fix issue when indirect descriptor is disabled
> > > - use UINT_MAX instead of vq->num to indicate no batching is pending
> > > - Tweak the comments for used_entry
> > > - Various coding style tweaks and typo fixes
> > > - Try to use in_order varianet in in_order ops
> >
> > Michael, any chance to make this for this merge window?
> >
> > Thanks
>
> want to fix last minor comments?

Yes, I will post a new version.

Thanks

>