Thomas Graf <post@xxxxxxxxxxxxxx> writes: > I tracked down an issue with using the Kernel 4.9.277 and 5.4.131 back > to this patch. > > In 802.11bg mode the effective transmit rate drops to 3MBit/s. > With that patch and perfect SNR (> 45dB) I get and rc_stats: > > ********************* > best __________rate_________ ________statistics________ > ________last_______ ______sum-of________ > rate [name idx airtime max_tp] [avg(tp) avg(prob) sd(prob)] > [prob.|retry|suc|att] [#success | #attempts] > 1 0 9738 0.9 0.9 93.7 0.5 75.0 > 1 3 4 562 572 > 2 1 4922 1.6 1.6 97.0 1.5 100.0 > 1 2 2 559 576 > 5.5 2 1858 4.7 4.7 99.9 0.0 100.0 > 2 2 2 542 565 > 11 3 982 9.1 9.1 94.9 1.2 100.0 > 4 3 3 560 578 > 6 4 1648 5.3 5.3 95.3 1.3 100.0 > 3 3 3 538 595 > 9 5 1112 8.0 8.0 97.5 1.8 100.0 > 4 2 2 560 596 > 12 6 844 10.5 10.5 92.4 2.0 75.0 > 5 3 4 572 615 > 18 7 576 15.5 15.4 89.0 1.4 66.6 > 5 2 3 559 609 > D 24 8 440 20.4 20.4 99.4 1.1 100.0 > 6 2 2 560 604 > C 36 9 308 29.1 29.1 98.7 1.6 100.0 > 6 2 2 565 600 > B 48 10 240 37.3 36.3 87.3 1.4 66.6 > 6 2 3 608 671 > A P 54 11 216 41.6 41.6 97.3 1.7 100.0 > 6 3 3 565 620 > > Total packet count:: ideal 6111 lookaround 652 > ********************* > > After reverting that patch the transmit rate is back to 20MBit/s: > ********************* > best __________rate_________ ________statistics________ > ________last_______ ______sum-of________ > rate [name idx airtime max_tp] [avg(tp) avg(prob) sd(prob)] > [prob.|retry|suc|att] [#success | #attempts] > 1 0 9738 0.9 0.9 99.8 0.6 100.0 > 1 0 0 41 44 > 2 1 4922 1.6 1.6 100.0 0.0 100.0 > 1 0 0 45 45 > 5.5 2 1858 4.7 4.7 99.9 0.0 100.0 > 2 0 0 43 44 > 11 3 982 9.1 9.1 97.0 1.4 100.0 > 4 0 0 44 45 > 6 4 1648 5.3 5.3 99.9 0.0 100.0 > 3 0 0 43 44 > 9 5 1112 8.0 8.0 99.9 0.0 100.0 > 4 0 0 45 47 > 12 6 844 10.5 8.8 74.9 0.7 0.0 > 5 0 0 43 47 > 18 7 576 15.5 15.5 100.0 0.0 100.0 > 5 0 0 42 42 > D 24 8 440 20.4 20.4 99.9 0.0 100.0 > 6 0 0 60 62 > C P 36 9 308 29.1 29.1 99.9 0.0 100.0 > 6 0 0 44 46 > A 48 10 240 37.3 37.3 93.8 1.2 100.0 > 6 1 1 587 618 > B 54 11 216 41.6 32.3 69.8 2.1 33.3 > 6 0 0 24506 25849 > > Total packet count:: ideal 4962 lookaround 552 > ********************* > > I'm using the ath9k driver with a sparklan WPEA-121N card. > > For my case reverting that patch is enough. > What I see is that IEEE80211_TX_CTL_RATE_CTRL_PROBE is set but not > used anywhere in the code. Maybe there is an easy and better fix than > just reverting. I lost track, is this regression resolved now or is it still open? -- https://patchwork.kernel.org/project/linux-wireless/list/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
