On Sat, 2017-05-06 at 16:09 -0700, Tom Herbert wrote: > On Sat, May 6, 2017 at 1:42 PM, Paolo Abeni <pab...@redhat.com> wrote: > > This patch series implement an idea suggested by Eric Dumazet to > > reduce the contention of the udp sk_receive_queue lock when the socket is > > under flood. > > > > An ancillary queue is added to the udp socket, and the socket always > > tries first to read packets from such queue. If it's empty, we splice > > the content from sk_receive_queue into the ancillary queue. > > > > The first patch introduces some helpers to keep the udp code small, and the > > following two implement the ancillary queue strategy. The code is split > > to hopefully help the reviewing process. > > > > The measured overall gain under udp flood is in the 20-35% range depending > > on > > the numa layout and the number of ingress queue used by the relevant nic. > > > > Certainly sounds good, but can you give real reproducible performance > numbers including the test that was run?
You are right, and I'm sorry, the cover letter was too terse. I used pktgen as sender, with 64 bytes packets, random src port on an host b2b connected via a 10Gbs link with the dut. On the receiver I used the udp_sink program by Jesper (https://github.c om/netoptimizer/network-testing/blob/master/src/udp_sink.c) and I configured an h/w l4 rx hash, so that I could control the number of ingress nic rx queues hit by the udp traffic via ethtool -L. The udp_sink program was bound to the first idle cpu, to get more stable numbers. Using a single numa note as receiver, I got the following: nic rx queues vanilla patched kernel 1 1820 kpps 1900 kpps 2 1950 kpps 2500 kpps 16 1670 kpps 2120 kpps When using a single nic rx queue I also enabled busy polling; elsewhere, in my scenario, the bh processing becames the bottle-neck and this produces large artifacts in the measured performances (e.g. improving the udp sink run time, decreases the overall tput, since more action from the scheduler comes into play). Cheers, Paolo
