On 2017年08月15日 00:01, Michael S. Tsirkin wrote:
On Sat, Aug 12, 2017 at 10:48:49AM +0800, Jason Wang wrote:
On 2017年08月12日 07:12, Jakub Kicinski wrote:
On Fri, 11 Aug 2017 19:41:18 +0800, Jason Wang wrote:
This patch tries to implement XDP for tun. The implementation was
split into two parts:
- fast path: small and no gso packet. We try to do XDP at page level
before build_skb(). For XDP_TX, since creating/destroying queues
were completely under control of userspace, it was implemented
through generic XDP helper after skb has been built. This could be
optimized in the future.
- slow path: big or gso packet. We try to do it after skb was created
through generic XDP helpers.
Test were done through pktgen with small packets.
xdp1 test shows ~41.1% improvement:
Before: ~1.7Mpps
After: ~2.3Mpps
xdp_redirect to ixgbe shows ~60% improvement:
Before: ~0.8Mpps
After: ~1.38Mpps
Suggested-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Jason Wang <jasow...@redhat.com>
Looks OK to me now :)
Out of curiosity, you say the build_skb() is for "small packets", and it
seems you are always reserving the 256B regardless of XDP being
installed. Does this have no performance impact on non-XDP case?
Have a test, only less than 1% were noticed which I think could be ignored.
Thanks
What did you test btw?
Pktgen
The biggest issue would be with something like
UDP with short packets.
Note that we do this only when sndbuf is INT_MAX. So this is probably
not an issue. The only thing matter is more stress to page allocator,
but according to the result of pktgen it was very small that could be
ignored.
Thanks
