On 2016-05-16 10:48, Hannu Nyman wrote: > I already said to Felix yesterday that I felt that with kernel 4.4 my ar71xx > WNDR3800 seemed somehow more sluggish. Now I tested the matter with "flent". > > And sadly, with kernel 4.4 my router's performance decreases significantly. > With kernel 4.1 the router achieves about 20% higher download throughput than > with the 4.4 build :-( > > I used "flent" to measure wired connection throughput with > - two LEDE builds: r241 with kernel 4.1 and r253 with kernel 4.4 > - two separate speed limits for SQM simple fq_codel QoS: 85000/10000 kb/s > that should leave some CPU power free in the router, and 110000/15000 that > should fully utilise the router's CPU. > - otherwise identical settings, all measurements made inside 30 minutes so no > changes in traffic conditions > > The achieved speeds were: > > r241 kernel 4.1 - 85/10: 79 Mb/s down, 8.1 Mb/s up > r253 kernel 4.4 - 85/10: 67 Mb/s down, 8.5 Mb/s up > > r241 kernel 4.1 - 110/15: 85 down, 10.5 up > r253 kernel 4.4 - 110/15: 70 down, 10.8 up > > (ping latency stays at 16-17 ms with all four tries) > > With both SQM speed limits, the kernel 4.1 build performs significantly > better. > > This performance decrease might be due to the kernel version bump to 4.4 or > the qdisc/codel changes made to the 4.4 patches a few days earlier. > > This chart sums it up: > https://www.dropbox.com/sh/89pntkzjxydnn4c/AAC4x9cScJERL9Wfxm4k43kma?dl=0&preview=Kernel41_44_comparison.png > > Full flent data (summary pics & rrul data files) for all four tries is > available in: > https://www.dropbox.com/sh/89pntkzjxydnn4c/AAC4x9cScJERL9Wfxm4k43kma?dl=0 I've also noticed a throughput decrease on other platforms, I don't have any hard data on that though. I've tried tracking down the source of this regression, but haven't gotten anywhere with that yet.
Once we're done with more urgent stuff, I plan to do some more work on optimizing the network stack. - Felix _______________________________________________ Lede-dev mailing list Lede-dev@lists.infradead.org http://lists.infradead.org/mailman/listinfo/lede-dev
