On 19/06/2015, Sebastian Moeller <moell...@gmx.de> wrote: > Hi Alan, > > excellent, thanks a million. > > On Jun 19, 2015, at 16:44 , Alan Jenkins > <alan.christopher.jenk...@gmail.com> wrote: > >> Hi >> >> I guess I've done the complementary half to Seb's test :). Basically >> "cake overhead 40" didn't work, but that's the fault of cake in this >> build. Or tc, as Johnathan suggested. (The "cake atm" part seems to >> work, as per my previous test). > > Great! > >> >> "tc qdisc" says "cake overhead 0", as Sebastian noticed. And the test >> results show "cake overhead 40" does not give a measurable >> improvement. But "tc stab overhead 40" does. >> >> I ran this test with the updated sqm-scripts and I think they're doing >> the right thing. > > Thanks for testing this, especially as I can not due to a lack of an > ADSL-link (and lack of cake actually, last I looked all I could find was > cookies in my browser and a promise of pie in my router) > >> >> >> Method: >> >> I used the updated files from sqm-scripts, >> >> (once I remembered to mark them executable. Lacking that causes a >> failure with no error messages, because sqm-scripts checks before >> running them :) >> >> but didn't bother updating & using luci-app-sqm. > > Ah, okay, I guess I did test this part with Dave’s help, so this should > work with the most recent sqm.lua. > >> >> The test was to compare netperf-runner results - ping during combined >> upload & download - for "overhead 40" and "overhead 0". I tested both >> values of linklayer_adaptation_mechanism. >> >> I had to repeat 6 times (60s per run for each overhead) because of >> random variation in the range of 3-4ms. I alternated "overhead 40" >> and "overhead 0" to try and exclude longer-term variation effects. >> >> With "stab overhead 40", median latency was better by about 3-4ms. >> With "cake overhead 40", there is no such effect. > > Intersting, when I still had a 6M/1M ADSL link, I saw much larger > latency > under load increases when setting the per packet overhead to small, but I > had my egress shaper running at 100% of line rate, so the system was rigged > for maximum effect that way. How are your shapers typically set?
For this test I try to push it, today I used 95%. I started trying 100%, which is still much better than unshaped. I was scared off by the random variation, I think it was higher at 100%. For long term use I reduce it, because I've seen the line rate vary slightly. (1020k up today, 912 a while back. Currently it reports a "max" figure I don't understand, it's about 1100 despite being rebooted daily. 16390k down). Alan _______________________________________________ Cerowrt-devel mailing list Cerowrt-devel@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/cerowrt-devel
