On Wed, 21 Sep 2016 21:56:58 +0200 Jesper Dangaard Brouer <bro...@redhat.com> wrote:
> > > I'm not opposed to running non-BPF code at XDP. I'm against adding > > > a linked list of hook consumers. > > I also worry about the performance impact of a linked list. We should > simple benchmark it instead of discussing it! ;-) (Note, there are some stability issue with this RFC patchset, when removing the xdp program, that I had to workaround/patch) I've started benchmarking this and I only see added cost of 2.89ns from these patches, at these crazy speeds it does correspond to -485Kpps. I was really expecting to see a higher cost of this approach. I tested this on two different machines. One was suppose to work with DDIO, but I could not get DDIO working on that machine (result in max 12.7Mpps drop). Even-though the mlx5 card does work with DDIO. Even removed the mlx5 and used same slot but no luck. (A side-note: Also measured a 16ns performance difference between which PCIe slot I'm using). The reason I wanted to benchmark this on a DDIO machine is, that I'm suspecting that the added cost, could be hiding behind the cache miss. Well, I'm running out-of-time benchmarking this stuff, I must prepare for my Network Performance Workshop ;-) (A side-note: my skylake motherboard also had a PCI slot, so I found an old e1000 NIC in my garage, and it worked!) -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer
