[dpdk-dev] [PATCH v14 00/10] implement packed virtqueues
Maxime Coquelin
maxime.coquelin at redhat.com
Tue Dec 18 15:02:08 CET 2018
On 12/17/18 10:31 PM, 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.
>
> With this patch set I see performance equal or slightly better (+2-3%) in a PVP
> scenario compared to split virtqueues (v18.11 in host)
>
> regards,
> Jens
>
> v13->v14:
> * replace (_)set_desc_avail()
> * remove unrelated changes in split vq code
> * remove trailing line
> * remove RING_EVENT_IDX code from virtqueue_enable_intr_packed()
> * set interrupt disable flag unconditionally
> * change error message for disabled control virtqueues
>
> v12->v13:
> * re-order patches 1-3 to address Maximes comment. Move all defines and
> data structures to patch one, all helpers to patch 2.
> * build-tested and ran checkpatch on all patches again
> * add split/packed versions for virtio_enable_intr()
> * remove redundant changes from split vq code
> * just return -1 when cq is enabled for packed vqs in virtio-user
>
> v11->v12:
> * add a patch to disable control vq when packed vq is enabled.
> I have a patch to support this but it needs a bit more work
> and I think it shouldn't stop this series from being applied
> * rework mergeable receive buffer code to be more efficient, by
> batching descriptor refill, similar to what Maxime proposed for
> split virtqueues
> * removed unnecessary checks in virtio_recv_mergeable_pkts_packed
> (Maxime)
> * Did not merge receive functions as Maxime suggested because it seemed
> to cause a small performance regression
> * Move event_flags_shadow from patch 3 to 1 (Maxime)
> * Did not merge xmit functions and call _split/_packed functions from
> there because it seemed to cause small performance drop (-0.5%)
> (Maxime)
>
> v10-v11:
> * this version includes some fixes from Tiwei, so I added his
> Signed-off-by to some of the patches
> * fix hang with mergable rx buffers (Tiwei)
> * clean-up code and simplify buffer handling (Tiwei)
> * rebase to current virtio-next master branch
>
> v9-v10:
> * don't mix index into buffer list and descriptors
> * whitespace and formatting issues
> * remove "VQ:" in dump virtqueue patch
> * add extra packed vring struct to virtqueue and change function
> prototypes and code accordingly
> * move wrap_counters to virtqueue
> * make if-conditions for packed and !packed more clear in
> set_rxtx_funcs()
> * initialize wrap counters in first patch, instead of rx and tx
> implementation patch
> * make virtio-user not supported with packed virtqueues, to
> be fixed in other patch set?
>
> 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 (9):
> net/virtio: add packed virtqueue defines
> net/virtio: add packed virtqueue helpers
> net/virtio: vring init for packed queues
> 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-user: fail if cq used with packed vq
> net/virtio: enable packed virtqueues by default
>
> Yuanhan Liu (1):
> net/virtio-user: add option to use packed queues
>
> drivers/net/virtio/virtio_ethdev.c | 228 +++++--
> drivers/net/virtio/virtio_ethdev.h | 8 +
> drivers/net/virtio/virtio_pci.h | 7 +
> drivers/net/virtio/virtio_ring.h | 58 +-
> drivers/net/virtio/virtio_rxtx.c | 611 +++++++++++++++++-
> .../net/virtio/virtio_user/virtio_user_dev.c | 27 +-
> .../net/virtio/virtio_user/virtio_user_dev.h | 2 +-
> drivers/net/virtio/virtio_user_ethdev.c | 14 +-
> drivers/net/virtio/virtqueue.c | 43 +-
> drivers/net/virtio/virtqueue.h | 109 +++-
> 10 files changed, 1044 insertions(+), 63 deletions(-)
>
Applied to dpdk-next-virtio
Thanks,
Maxime
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