MT7986 - temporarily ping spikes and terrible WiFi performance - 5GHz, 160 MHz

[b0nef1re]

Subject of the issue

Massive ping spikes and a bad WiFi performance (<50Mbit) are randomly occurring with the MT7986 chipset on both bands

Your environment

• MT6000 & TUF-AX6000
• Latest snapshot (r26128) & 23.05.3
• Public WiFi
• WED disabled, no software or hardware offloading, 5GHz, 160MHZ, client isolation on

Expected behavior

Stable and fast WiFi performance during the "good times":

Actual behavior

I'm having random horrible ping and WiFi performance problems with the MT7986 driver. This happens on the MT6000 and also the Asus TUF-AX6000 with all 5GHz and also sometimes 2.4 GHz clients, which are connected at the same time. The problems always occur every 10-30min lasting for around 5-10min until everything returns to normal. No errors in the logs. Via LAN cable the connection is always fast and stable.

This problem happened so far with every OpenWRT version which i tried. It does not happen with the stock firmware of both devices.

I have the feeling that its caused by specific WiFi clients, but it also seems to happen when AP-STA-POLL-OK is being sent.

[pesa1234]

AP-STA-POLL-OK your device is still connected to the network? Can you please post your wi-fi config?

cat /etc/config/wireless remove mac and password

After 2 days of check I didn't get your issue

[b0nef1re]

config wifi-device 'radio0'
        option type 'mac80211'
        option path 'platform/soc/18000000.wifi'
        option channel '1'
        option band '2g'
        option htmode 'HE20'
        option country 'DE'
        option cell_density '0'
        option txpower '20'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'xxxxxxxx'
        option encryption 'none'
        option key 'xxxxxxxxxxx'
        option isolate '1'

config wifi-device 'radio1'
        option type 'mac80211'
        option path 'platform/soc/18000000.wifi+1'
        option channel '116'
        option band '5g'
        option htmode 'HE160'
        option cell_density '0'
        option country 'DE'
        option txpower '26'

config wifi-iface 'default_radio1'
        option device 'radio1'
        option network 'lan'
        option mode 'ap'
        option ssid 'xxxxxxxxxxxx'
        option encryption 'none'
        option key 'xxxxxxxxxxx'
        option isolate '1'

config wifi-iface 'wifinet2'
        option device 'radio0'
        option mode 'ap'
        option ssid 'FreeWLAN'
        option encryption 'none'
        option isolate '1'
        option network 'lan'

config wifi-iface 'wifinet3'
        option device 'radio1'
        option mode 'ap'
        option ssid 'freifunk'
        option encryption 'none'
        option isolate '1'
        option network 'lan'

config wifi-iface 'wifinet4'
        option device 'radio1'
        option mode 'ap'
        option ssid 'freifunkxxx'
        option encryption 'owe'
        option isolate '1'
        option network 'lan'

[pesa1234]

When you get the message AP-STA-POLL-OK your device is still present on network?

[cliobrando]

Redmi AX6000 here, same behavior, only some clients. 5Ghz - 40Mhz Samsung S21 (Wifi 6): > 200Mbps Vivo Y35 (Wifi 5): < 25Mbps

[b0nef1re]

When you get the message AP-STA-POLL-OK your device is still present on network?

AP-STA-POLL-OK is getting sent to clients which seem to be already offline. But the ping spikes also happen without the AP-STA-POLL_OK message.

[ehfd]

I reproduce this issue in GL.iNet GL-MT6000 on r26308-4341901f05 with an Intel AX201 client (Windows) on 5GHz 160MHz.

The ping spike doesn't occur while pining to my ISP DNS inside the router or using wired LAN.

WED is disabled as well.

[lukasz1992]

Maybe there is a fix here: https://github.com/openwrt/openwrt/pull/15824 ?

[burny0202]

I think I may be experiencing this as well; I had put it down to other things at the time.

@b0nef1re - How did you record the nice latency graphs? I have been sat trying to watch pings