Re: [PATCH net-next V5 0/9] vhost_net rx batch dequeuing

Jason Wang
2017-05-19T06:27:28Z

On 2017年05月18日 04:59, Michael S. Tsirkin wrote:
> On Wed, May 17, 2017 at 12:14:36PM +0800, Jason Wang wrote:
>> This series tries to implement rx batching for vhost-net. This is done
>> by batching the dequeuing from skb_array which was exported by
>> underlayer socket and pass the sbk back through msg_control to finish
>> userspace copying. This is also the requirement for more batching
>> implemention on rx path.
>>
>> Tests shows at most 7.56% improvment bon rx pps on top of batch
>> zeroing and no obvious changes for TCP_STREAM/TCP_RR result.
>>
>> Please review.
>>
>> Thanks
> A surprisingly large gain for such as simple change. It would be nice
> to understand better why this helps - in particular, does the optimal
> batch size change if ring is bigger or smaller?

Will test, just want to confirm. You mean virtio ring not tx_queue_len here?

Thanks

> But let's merge it
> meanwhile.
>
> Series:
>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
>
>
>
>> Changes from V4:
>> - drop batch zeroing patch
>> - renew the performance numbers
>> - move skb pointer array out of vhost_net structure
>>
>> Changes from V3:
>> - add batch zeroing patch to fix the build warnings
>>
>> Changes from V2:
>> - rebase to net-next HEAD
>> - use unconsume helpers to put skb back on releasing
>> - introduce and use vhost_net internal buffer helpers
>> - renew performance numbers on top of batch zeroing
>>
>> Changes from V1:
>> - switch to use for() in __ptr_ring_consume_batched()
>> - rename peek_head_len_batched() to fetch_skbs()
>> - use skb_array_consume_batched() instead of
>> skb_array_consume_batched_bh() since no consumer run in bh
>> - drop the lockless peeking patch since skb_array could be resized, so
>> it's not safe to call lockless one
>>
>> Jason Wang (8):
>> skb_array: introduce skb_array_unconsume
>> ptr_ring: introduce batch dequeuing
>> skb_array: introduce batch dequeuing
>> tun: export skb_array
>> tap: export skb_array
>> tun: support receiving skb through msg_control
>> tap: support receiving skb from msg_control
>> vhost_net: try batch dequing from skb array
>>
>> Michael S. Tsirkin (1):
>> ptr_ring: add ptr_ring_unconsume
>>
>> drivers/net/tap.c | 25 +++++++--
>> drivers/net/tun.c | 31 ++++++++---
>> drivers/vhost/net.c | 128 +++++++++++++++++++++++++++++++++++++++++++---
>> include/linux/if_tap.h | 5 ++
>> include/linux/if_tun.h | 5 ++
>> include/linux/ptr_ring.h | 120 +++++++++++++++++++++++++++++++++++++++++++
>> include/linux/skb_array.h | 31 +++++++++++
>> 7 files changed, 327 insertions(+), 18 deletions(-)
>>
>> --
>> 2.7.4