Degraded performance with Intel 7265 wireless on iwm driver

Alex O'Brien alex at emobrien.com
Sun Jul 23 22:16:42 UTC 2017


I'm new to FreeBSD so please be at least somewhat forgiving of any
silly mistakes in my diagnostics.

I recently installed FreeBSD on a Lenovo Thinkpad Yoga laptop, which
has an Intel 7265 wireless chip. Everything but wireless seems to be
working flawlessly (hooray). With regards to wireless, it seems to
perform initially normally, but performance degrades severely after a
short period of use.

The performance degradation can be briefly reversed with service netif
restart, but quickly returns.

I noticed that as the performance degrades, the listed speed in
ifconfig decreases.

Initially:
> wlan0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
>         ether 34:02:86:e7:85:4c
>         inet 192.168.0.30 netmask 0xffffff00 broadcast 192.168.0.255
>         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>         media: IEEE 802.11 Wireless Ethernet OFDM/36Mbps mode 11g
>         status: associated
>         ssid "ssid" channel 9 (2452 MHz 11g) bssid 58:8b:f3:e4:00:a0
>         regdomain FCC country US authmode WPA2/802.11i privacy ON
>         deftxkey UNDEF TKIP 3:128-bit txpower 30 bmiss 10 scanvalid 60
>         protmode CTS wme roaming MANUAL
>         groups: wlan

Shortly after:
> wlan0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
>         ether 34:02:86:e7:85:4c
>         inet 192.168.0.30 netmask 0xffffff00 broadcast 192.168.0.255
>         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>         media: IEEE 802.11 Wireless Ethernet DS/11Mbps mode 11g
>         status: associated
>         ssid "ssid" channel 9 (2452 MHz 11g) bssid 58:8b:f3:e4:00:a0
>         regdomain FCC country US authmode WPA2/802.11i privacy ON
>         deftxkey UNDEF TKIP 3:128-bit txpower 30 bmiss 10 scanvalid 60
>         protmode CTS wme roaming MANUAL
>         groups: wlan

And finally:
> wlan0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
>         ether 34:02:86:e7:85:4c
>         inet 192.168.0.30 netmask 0xffffff00 broadcast 192.168.0.255
>         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>         media: IEEE 802.11 Wireless Ethernet DS/1Mbps mode 11g
>         status: associated
>         ssid "ssid" channel 9 (2452 MHz 11g) bssid 58:8b:f3:e4:00:a0
>         regdomain FCC country US authmode WPA2/802.11i privacy ON
>         deftxkey UNDEF TKIP 2:128-bit TKIP 3:128-bit txpower 30 bmiss 10
>         scanvalid 60 protmode CTS wme roaming MANUAL
>         groups: wlan

Additionally, with wlandebug +rate enabled, there are repeated
messages about "decreasing rate", starting at 72, ending at 2:

> Jul 23 14:55:09 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 72, txcnt=11, retrycnt=19
> Jul 23 14:55:09 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR decreasing rate 48 (txcnt=11 retrycnt=19)
> Jul 23 14:55:10 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 48, txcnt=11, retrycnt=1
> Jul 23 14:55:11 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 48, txcnt=33, retrycnt=24
> Jul 23 14:55:11 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR decreasing rate 36 (txcnt=33 retrycnt=24)
> Jul 23 14:55:11 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 36, txcnt=83, retrycnt=35
> Jul 23 14:55:11 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR decreasing rate 24 (txcnt=83 retrycnt=35)
> Jul 23 14:55:12 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 24, txcnt=68, retrycnt=25
> Jul 23 14:55:12 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR decreasing rate 22 (txcnt=68 retrycnt=25)
> Jul 23 14:55:12 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 22, txcnt=53, retrycnt=19
> Jul 23 14:55:12 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR decreasing rate 18 (txcnt=53 retrycnt=19)
> Jul 23 14:55:14 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 18, txcnt=11, retrycnt=1
> Jul 23 14:55:14 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 18, txcnt=87, retrycnt=23
> Jul 23 14:55:15 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 18, txcnt=111, retrycnt=27Jul 23 14:55:18 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 18, txcnt=64, retrycnt=8
> Jul 23 14:55:19 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 18, txcnt=11, retrycnt=0
> Jul 23 14:55:19 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR increasing rate 22 (txcnt=11 retrycnt=0)
> Jul 23 14:55:20 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 22, txcnt=157, retrycnt=42Jul 23 14:55:20 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 22, txcnt=240, retrycnt=47
> Jul 23 14:55:21 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 22, txcnt=24, retrycnt=15
> Jul 23 14:55:21 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR decreasing rate 18 (txcnt=24 retrycnt=15)
> Jul 23 14:55:21 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 18, txcnt=35, retrycnt=10
> Jul 23 14:55:22 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 18, txcnt=67, retrycnt=18
> Jul 23 14:55:22 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 18, txcnt=114, retrycnt=56
> Jul 23 14:55:22 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR decreasing rate 12 (txcnt=114 retrycnt=56)
> Jul 23 14:55:23 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 12, txcnt=47, retrycnt=17
> Jul 23 14:55:23 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR decreasing rate 11 (txcnt=47 retrycnt=17)
> Jul 23 14:55:23 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 11, txcnt=13, retrycnt=10
> Jul 23 14:55:23 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR decreasing rate 4 (txcnt=13 retrycnt=10)Jul 23 14:55:24 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 4, txcnt=26, retrycnt=20
> Jul 23 14:55:24 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR decreasing rate 2 (txcnt=26 retrycnt=20)Jul 23 14:55:24 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 2, txcnt=21, retrycnt=7
> Jul 23 14:55:25 hostname kernel: wlan0: [58:8b:f3:e4:00:a0] AMRR: current rate 2, txcnt=16, retrycnt=2

My immediate suspicion is that this might be an issue with the iwm
driver, but I have no idea how to further diagnose the issue in order
to confirm or deny that.
If anyone could point me in the right direction, it would be greatly
appreciated.


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