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

Jason Wang
2016-06-30T04:01:32Z

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

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(-)

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2.7.4