On 2016-03-07 15:05, Avery Pennarun wrote: > On Fri, Mar 4, 2016 at 1:32 AM, Michal Kazior <michal.kaz...@tieto.com> wrote: >> On 4 March 2016 at 03:48, Tim Shepard <s...@alum.mit.edu> wrote: >> [...] >>> (I am interested in knowing what other mac80211 drivers have been >>> modified to use the mac80211 intermediate software queues. I know >>> Michal mentioned he has patches for ath10k that are not yet released, >>> and I know Felix is finishing up the mt76 driver which uses them.) >> >> Patches for ath10k are under review since quite some time now (but are >> not merged yet). The latest re-spin is: >> >> http://lists.infradead.org/pipermail/ath10k/2016-March/006923.html > > Hi all, on Friday I had a chance to experiment with some of these > patches, specifically Tim's ath9k patch (to use intermediate queues), > plus MIchal's patch to use fq_codel with the intermediate queues. I > didn't attempt any fine tuning; I just slapped them together to see > what happens. (I tried applying Michal's ath10k patches too, but got > stuck since they seem to be applied against the upstream v4.4 kernel > and didn't merge cleanly with the latest mac80211 branch. Maybe I was > doing something wrong.) > > Test setup: > AP (ath9k) -> 2x2 strong signal -> STA1 (mwifiex) > -> attenuator (-40 dB) -> 1x1 weak signal -> STA2 (mwifiex) > > STA2 generally gets modulation levels around MCS0-2 and STA1 usually > gets something like MCS12-15. > > With or without this patch, results with TCP iperf were fishy - I > think packet loss patterns were particularly bad and caused 2-second > TCP retry timeouts occasionally - so I removed TCP from the test and > switched the UDP iperf instead. > > I ran isoping > (https://gfiber.googlesource.com/vendor/google/platform/+/master/cmds/isoping.c) > from the AP to both stations to measure two-way latency during all > tests. (I used -r2 for two packets/sec in each direction in order not > to affect the test results too much.) > > Overall results: > > - Running one iperf at a time, I saw ~45 Mbps to STA1 and ~7 Mbps to STA2. > > - Running both iperfs at once, without the patches, latencies got > extremely high (~600ms sometimes) and results were closer to > byte-fairness than airtime-fairness (ie. ~7 Mbps each). > > - Running both iperfs at once, with the patches, latencies were still > high (usually high 2-digit, sometimes low 3-digit latencies) but we > got closer to airtime-fairness than byte-fairness (~17 Mbps and ~2 > Mbps). > > - With only one iperf running, without the patches, latencies were > high to both stations. With the patches, latency was > mid-double-digits to the non-iperf station (pretty good!) while being > low-mid triple-digits to the busy iperf station. This suggests that > we are getting per-station queuing (yay!) but does make me question > whether the fq_ in fq_codel was working. Please change the 'if (flow->txqi)' check in ieee80211_txq_enqueue to: if (flow->txqi && flow->txqi != txqi) This should hopefully fix the fq_ part ;)
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