On Thu, Aug 13, 2015 at 03:10:33PM +0200, Jesper Dangaard Brouer wrote: > > On Thu, 13 Aug 2015 03:13:40 +0200 Phil Sutter <p...@nwl.cc> wrote: > > > On Tue, Aug 11, 2015 at 06:13:49PM -0700, Alexei Starovoitov wrote: > > > > In general 'changing the default' may be an acceptable thing, but then > > > it needs to strongly justified. How much performance does it bring? > > > > A quick test on my local VM with veth and netperf (netserver and veth > > peer in different netns) I see an increase of about 5% of throughput > > when using noqueue instead of the default pfifo_fast. > > Good that you can show 5% improvement with a single netperf flow. We > are saving approx 6 atomic operations avoiding the qdisc code path. > > This fixes a scalability issue with veth. Thus, the real performance > boost will happen with multiple flows and multiple CPU cores in > action. You can try with a multi core VM and use super_netperf. > > https://github.com/borkmann/stuff/blob/master/super_netperf
I actually used that on my VM as well, but the difference between a single and ten streams in parallel was negligible. In order to avoid tampering the results, I tested again on a physical system with four cores, ran each benchmark ten times and built an average over the results. This showed an increase in throughput of about 35% with a single stream and about 10% with ten streams in parallel. Not sure though why the improvement is bigger in the first case if there really is a scalability problem as you say. Cheers, Phil -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
