Re: [PATCH net-next V3 0/6] switch to use tx skb array in tun

Michael S. Tsirkin
2016-06-30T05:38:17Z

On Thu, Jun 30, 2016 at 11:52:53AM +0800, Jason Wang wrote:
> Hi all:
>
> This series tries to switch to use skb array in tun. This is used to
> eliminate the spinlock contention between producer and consumer. The
> conversion was straightforward: just introdce a tx skb array and use
> it instead of sk_receive_queue.
>
> A minor issue is to keep the tx_queue_len behaviour, since tun used to
> use it for the length of sk_receive_queue. This is done through:
>
> - add the ability to resize multiple rings at once to avoid handling
> partial resize failure for mutiple rings.
> - add the support for zero length ring.
> - introduce a notifier which was triggered when tx_queue_len was
> changed for a netdev.
> - resize all queues during the tx_queue_len changing.
>
> Tests shows about 15% improvement on guest rx pps:
>
> Before: ~1300000pps
> After : ~1500000pps

Series:

Acked-by: Michael S. Tsirkin <mst@redhat.com>

> Changes from V2:
> - add multiple rings resizing support for ptr_ring/skb_array
> - add zero length ring support
> - introdce a NETDEV_CHANGE_TX_QUEUE_LEN
> - drop new flags
>
> Changes from V1:
> - switch to use skb array instead of a customized circular buffer
> - add non-blocking support
> - rename .peek to .peek_len
> - drop lockless peeking since test show very minor improvement
>
> Jason Wang (5):
> ptr_ring: support zero length ring
> skb_array: minor tweak
> skb_array: add wrappers for resizing
> net: introduce NETDEV_CHANGE_TX_QUEUE_LEN
> tun: switch to use skb array for tx
>
> Michael S. Tsirkin (1):
> ptr_ring: support resizing multiple queues
>
> drivers/net/tun.c | 138 ++++++++++++++++++++++++++++++++++++---
> drivers/vhost/net.c | 16 ++++-
> include/linux/net.h | 1 +
> include/linux/netdevice.h | 1 +
> include/linux/ptr_ring.h | 77 ++++++++++++++++++----
> include/linux/skb_array.h | 13 +++-
> net/core/net-sysfs.c | 15 ++++-
> tools/virtio/ringtest/ptr_ring.c | 5 ++
> 8 files changed, 243 insertions(+), 23 deletions(-)
>
> --
> 2.7.4