Re: [PATCH net-next V2 3/3] tap: XDP support
- Date: Fri, 11 Aug 2017 16:12:23 -0700
- From: Jakub Kicinski <kubakici@xxxxx>
- Subject: Re: [PATCH net-next V2 3/3] tap: XDP support
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 <mst@xxxxxxxxxx>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
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?