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

[Michael S. Tsirkin]

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: ~130pps
> After : ~150pps

Series:

Acked-by: Michael S. Tsirkin 


> 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

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

[Jason Wang]

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: ~130pps
After : ~150pps

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