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

From: Jason Wang
Date: Fri May 19 2017 - 02:27:30 EST




On 2017å05æ18æ 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@xxxxxxxxxx>



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(-)

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