On 10.07.2021 02:16, Rafał Miłecki wrote:
So it seems there are two problems I managed to narrown down:
1. On MT7603 "rx bitrate" of STA drops 72.2 → 6 MBit/s regularly
2. When catching up with traffic (after slow down) WiFi occasionally stalls
Today I decided to use my Netgear R6220's 5 GHz (MT7612EN).
On that chipset "rx bitrate" reported for my STA stays between 292 and
390 for most of them time BUT is also regularly drops to 6 Mbps:
> while [ 1 ]; do date; iw dev wlan1 station dump | grep bitrate; sleep 1; done
Sat Jul 10 15:00:27 UTC 2021
tx bitrate: 292.5 MBit/s VHT-MCS 7 80MHz VHT-NSS 1
rx bitrate: 390.0 MBit/s VHT-MCS 9 80MHz VHT-NSS 1
Sat Jul 10 15:00:28 UTC 2021
tx bitrate: 433.3 MBit/s VHT-MCS 9 80MHz short GI VHT-NSS 1
rx bitrate: 390.0 MBit/s VHT-MCS 8 80MHz short GI VHT-NSS 1
Sat Jul 10 15:00:29 UTC 2021
tx bitrate: 433.3 MBit/s VHT-MCS 9 80MHz short GI VHT-NSS 1
rx bitrate: 325.0 MBit/s VHT-MCS 7 80MHz short GI VHT-NSS 1
Sat Jul 10 15:00:30 UTC 2021
tx bitrate: 390.0 MBit/s VHT-MCS 9 80MHz VHT-NSS 1
rx bitrate: 6.0 MBit/s
Sat Jul 10 15:00:32 UTC 2021
tx bitrate: 292.5 MBit/s VHT-MCS 7 80MHz VHT-NSS 1
rx bitrate: 6.0 MBit/s
Sat Jul 10 15:00:33 UTC 2021
tx bitrate: 390.0 MBit/s VHT-MCS 8 80MHz short GI VHT-NSS 1
rx bitrate: 325.0 MBit/s VHT-MCS 7 80MHz short GI VHT-NSS 1
Sat Jul 10 15:00:34 UTC 2021
tx bitrate: 292.5 MBit/s VHT-MCS 7 80MHz VHT-NSS 1
rx bitrate: 325.0 MBit/s VHT-MCS 7 80MHz short GI VHT-NSS 1
Sat Jul 10 15:00:35 UTC 2021
tx bitrate: 390.0 MBit/s VHT-MCS 8 80MHz short GI VHT-NSS 1
rx bitrate: 325.0 MBit/s VHT-MCS 7 80MHz short GI VHT-NSS 1
Sat Jul 10 15:00:36 UTC 2021
tx bitrate: 390.0 MBit/s VHT-MCS 9 80MHz VHT-NSS 1
rx bitrate: 325.0 MBit/s VHT-MCS 7 80MHz short GI VHT-NSS 1
Whenever it drops to 6 MBit/s I can see iperf slowing down from 150 -
180 Mb/s down to 100 - 130 Mb/s;
[ 3] 19148.0-19149.0 sec 19.1 MBytes 160 Mbits/sec
[ 3] 19149.0-19150.0 sec 21.9 MBytes 184 Mbits/sec
[ 3] 19150.0-19151.0 sec 18.6 MBytes 156 Mbits/sec
[ 3] 19151.0-19152.0 sec 21.2 MBytes 178 Mbits/sec
[ 3] 19152.0-19153.0 sec 15.6 MBytes 131 Mbits/sec ← "iw" on MT7612EN reported 6 Mb/s "rx bitrate" at that moment
[ 3] 19153.0-19154.0 sec 18.8 MBytes 157 Mbits/sec
[ 3] 19154.0-19155.0 sec 20.0 MBytes 168 Mbits/sec
[ 3] 19155.0-19156.0 sec 20.4 MBytes 171 Mbits/sec
[ 3] 19156.0-19157.0 sec 19.6 MBytes 165 Mbits/sec
[ 3] 19157.0-19158.0 sec 20.2 MBytes 170 Mbits/sec
[ 3] 19158.0-19159.0 sec 21.6 MBytes 181 Mbits/sec
(...)
[ 3] 19207.0-19208.0 sec 18.4 MBytes 154 Mbits/sec
[ 3] 19208.0-19209.0 sec 18.1 MBytes 152 Mbits/sec
[ 3] 19209.0-19210.0 sec 17.6 MBytes 148 Mbits/sec
[ 3] 19210.0-19211.0 sec 18.6 MBytes 156 Mbits/sec
[ 3] 19211.0-19212.0 sec 22.2 MBytes 187 Mbits/sec
[ 3] 19212.0-19213.0 sec 15.1 MBytes 127 Mbits/sec ← "iw" on MT7612EN reported 6 Mb/s "rx bitrate" at that moment
[ 3] 19213.0-19214.0 sec 16.9 MBytes 142 Mbits/sec
[ 3] 19214.0-19215.0 sec 17.1 MBytes 144 Mbits/sec
[ 3] 19215.0-19216.0 sec 20.2 MBytes 170 Mbits/sec
[ 3] 19216.0-19217.0 sec 21.1 MBytes 177 Mbits/sec
[ 3] 19217.0-19218.0 sec 21.6 MBytes 181 Mbits/sec
(...)
[ 3] 19267.0-19268.0 sec 15.9 MBytes 133 Mbits/sec
[ 3] 19268.0-19269.0 sec 18.2 MBytes 153 Mbits/sec
[ 3] 19269.0-19270.0 sec 17.2 MBytes 145 Mbits/sec
[ 3] 19270.0-19271.0 sec 17.0 MBytes 143 Mbits/sec
[ 3] 19271.0-19272.0 sec 18.2 MBytes 153 Mbits/sec
[ 3] 19272.0-19273.0 sec 15.2 MBytes 128 Mbits/sec ← "iw" on MT7612EN reported 6 Mb/s "rx bitrate" at that moment
[ 3] 19273.0-19274.0 sec 14.0 MBytes 117 Mbits/sec ← "iw" on MT7612EN reported 6 Mb/s "rx bitrate" at that moment
[ 3] 19274.0-19275.0 sec 18.9 MBytes 158 Mbits/sec
[ 3] 19275.0-19276.0 sec 16.9 MBytes 142 Mbits/sec
[ 3] 19276.0-19277.0 sec 18.6 MBytes 156 Mbits/sec
[ 3] 19277.0-19278.0 sec 16.2 MBytes 136 Mbits/sec
[ 3] 19278.0-19279.0 sec 23.9 MBytes 200 Mbits/sec
[ 3] 19279.0-19280.0 sec 21.1 MBytes 177 Mbits/sec
(...)
[ 3] 19297.0-19298.0 sec 21.6 MBytes 181 Mbits/sec
[ 3] 19298.0-19299.0 sec 19.9 MBytes 167 Mbits/sec
[ 3] 19299.0-19300.0 sec 22.9 MBytes 192 Mbits/sec
[ 3] 19300.0-19301.0 sec 21.4 MBytes 179 Mbits/sec
[ 3] 19301.0-19302.0 sec 19.6 MBytes 165 Mbits/sec
[ 3] 19302.0-19303.0 sec 15.0 MBytes 126 Mbits/sec ← "iw" on MT7612EN reported 6 Mb/s "rx bitrate" at that moment
[ 3] 19303.0-19304.0 sec 11.0 MBytes 92.3 Mbits/sec
[ 3] 19304.0-19305.0 sec 11.2 MBytes 94.4 Mbits/sec
[ 3] 19305.0-19306.0 sec 20.1 MBytes 169 Mbits/sec
[ 3] 19306.0-19307.0 sec 18.4 MBytes 154 Mbits/sec
[ 3] 19307.0-19308.0 sec 21.1 MBytes 177 Mbits/sec
[ 3] 19308.0-19309.0 sec 22.6 MBytes 190 Mbits/sec
[ 3] 19309.0-19310.0 sec 21.5 MBytes 180 Mbits/sec
[ 3] 19310.0-19311.0 sec 20.0 MBytes 168 Mbits/sec
In 5 GHz case however mt76 successfully recovers from all those slow
downs. Traffic didn't stop for good not even once. I had it running
for over 5 hours:
[ 3] 0.0-19330.1 sec 352 GBytes 157 Mbits/sec
