[dpdk-dev] [PATCH v4 0/4] net/virtio: make virtqueue struct cache-friendly

[Balazs Nemeth]

On Tue, 2021-03-16 at 10:38 +0100, Maxime Coquelin wrote:
> This series optimizes the cache usage of virtqueue struct,
> by making a "fake" mbuf being dynamically allocated in Rx
> virtnet struct, by removing a useless virtuque pointer
> into the virtnet structs and by moving a few fields
> to pack holes.
> 
> With these 3 patches, the virtqueue struct size goes from
> 576 bytes (9 cachelines) to 248 bytes (4 cachelines).
> 
> Changes in v4:
> ==============
> - Fix ARM build failure after rebase (0-day robot)
> - Fix fake_mbuf freeing (David)
> - Applied David R-by
> 
> Changes in v3:
> ==============
> - Use rte_zmalloc_socket for fake mbuf alloc (David)
> - Fix typos in commit messages
> - Remove superfluous pointer check befor freeing (David)
> - Fix checkpatch warnings
> 
> Changes in v2:
> ==============
> - Rebase on latest main
> - Improve error path in virtio_init_queue
> - Fix various typos in commit messages
> 
> Maxime Coquelin (4):
>   net/virtio: remove reference to virtqueue in vrings
>   net/virtio: improve queue init error path
>   net/virtio: allocate fake mbuf in Rx queue
>   net/virtio: pack virtqueue struct
> 
>  drivers/net/virtio/virtio_ethdev.c            | 64 +++++++++++--------
>  drivers/net/virtio/virtio_rxtx.c              | 37 +++++------
>  drivers/net/virtio/virtio_rxtx.h              |  5 +-
>  drivers/net/virtio/virtio_rxtx_packed.c       |  4 +-
>  drivers/net/virtio/virtio_rxtx_packed.h       |  6 +-
>  drivers/net/virtio/virtio_rxtx_packed_avx.h   |  4 +-
>  drivers/net/virtio/virtio_rxtx_packed_neon.h  |  4 +-
>  drivers/net/virtio/virtio_rxtx_simple.h       |  2 +-
>  .../net/virtio/virtio_rxtx_simple_altivec.c   |  2 +-
>  drivers/net/virtio/virtio_rxtx_simple_neon.c  |  2 +-
>  drivers/net/virtio/virtio_rxtx_simple_sse.c   |  2 +-
>  .../net/virtio/virtio_user/virtio_user_dev.c  |  4 +-
>  drivers/net/virtio/virtio_user_ethdev.c       |  2 +-
>  drivers/net/virtio/virtqueue.h                | 24 ++++---
>  14 files changed, 87 insertions(+), 75 deletions(-)
> 


Tested this in a PVP setup on ARM, giving a slight improvement in
performance. For the series:

Tested-by: Balazs Nemeth <bnemeth at redhat.com>