This build is from stable/12 rather than HEAD, so it may not be broken there,
if that's any help.
On 16/09/2020 23:50, Adrian Chadd wrote:
Hi!
Dang, ok. Well, rtwn was broken on freebsd-head due to changes elsewhere so we need to get those fixed before we can see
what's up with it.
I'll post updates to freebsd-wireless if/when I figure it out. :P
-adrian
On Wed, 16 Sep 2020 at 15:43, James Wright <james.wri...@digital-chaos.com
<mailto:james.wri...@digital-chaos.com>> wrote:
On 16/09/2020 22:36, Adrian Chadd wrote:
>
>
> On Wed, 16 Sep 2020 at 13:41, James Wright
<james.wri...@digital-chaos.com
<mailto:james.wri...@digital-chaos.com>
<mailto:james.wri...@digital-chaos.com
<mailto:james.wri...@digital-chaos.com>>> wrote:
>
> Hi wireless gurus,
>
> I'm trying to understand why this USB wifi dongle is so slow
under FreeBSD.
> The max real-world download rate seems to be capped at ~900KB/sec
(see wget below),
> but with exactly the same hardware and conditions under Win10 I
reach ~3MB/sec.
>
>
> OS: FreeBSD 12.2-PRERELEASE (r365055)
> Router: Virgin Media SuperHub 3 (802.11a/b/g/n/ac)
> Hardware: Edimax EW-7811Un (RTL8188CUS)
> Driver: rtwn
>
> % grep wlan /etc/rc.conf
> wlans_rtwn0="wlan0"
> ifconfig_wlan0="WPA SYNCDHCP"
> create_args_wlan0="country GB
>
> % dmesg | grep rtwn
> rtwn0 on uhub0
> rtwn0: <Realtek 802.11n WLAN Adapter, class 0/0, rev 2.00/2.00, addr
1> on usbus0
> rtwn0: MAC/BB RTL8188CUS, RF 6052 1T1R
>
> % sysctl dev.rtwn
> dev.rtwn.0.rx_buf_size: 24
> dev.rtwn.0.ratectl_selected: 1
> dev.rtwn.0.ratectl: 1
> dev.rtwn.0.hwcrypto: 1
> dev.rtwn.0.debug: 0
> dev.rtwn.0.ht40: 0
> dev.rtwn.0.%parent: uhub0
> dev.rtwn.0.%pnpinfo: vendor=0x7392 product=0x7811 devclass=0x00
devsubclass=0x00 devproto=0x00
sernum="00e04c000001"
> release=0x0200 mode=host intclass=0xff intsubclass=0xff
intprotocol=0xff
> dev.rtwn.0.%location: bus=0 hubaddr=1 port=1 devaddr=2 interface=0
ugen=ugen0.2
> dev.rtwn.0.%driver: rtwn
> dev.rtwn.0.%desc: Realtek 802.11n WLAN Adapter, class 0/0, rev
2.00/2.00, addr 1
> dev.rtwn.%parent:
>
> % ifconfig wlan0
> wlan0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0
mtu 1500
> ether 74:da:38:8b:e1:10
> inet 192.168.0.12 netmask 0xffffff00 broadcast
192.168.0.255
> groups: wlan
> ssid VM5909357 channel 6 (2437 MHz 11g ht/20) bssid
c0:05:c2:57:8d:69
> regdomain ETSI country GB authmode WPA2/802.11i privacy ON
> deftxkey UNDEF AES-CCM 2:128-bit AES-CCM 3:128-bit txpower
30 bmiss 7
> scanvalid 60 protmode CTS ht20 ampdulimit 64k ampdudensity
8 shortgi
> -stbc -ldpc wme roaming MANUAL
> media: IEEE 802.11 Wireless Ethernet MCS mode 11ng
> status: associated
> nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>
> % ifconfig wlan0 scan
> SSID/MESH ID BSSID CHAN RATE
S:N INT CAPS
> VM5909357 c0:05:c2:57:8d:69 6 54M
-78:-95 100 EPS HTCAP WME ATH RSN
>
> % ifconfig wlan0 list sta
> ADDR AID CHAN RATE RSSI IDLE TXSEQ RXSEQ CAPS FLAG
> c0:05:c2:57:8d:69 1 6 65M 21.5 0 28562 4816 EPS
AQEHTRs HTCAP WME ATH RSN (rssi 0.0:0.0:0.0:0.0 nf
> 0:0:0:0)
>
> % wget
https://download.freebsd.org/ftp/releases/amd64/amd64/ISO-IMAGES/12.1/FreeBSD-12.1-RELEASE-amd64-dvd1.iso
> FreeBSD-12.1-RELEASE-amd64-dvd1.iso
>
<https://download.freebsd.org/ftp/releases/amd64/amd64/ISO-IMAGES/12.1/FreeBSD-12.1-RELEASE-amd64-dvd1.isoFreeBSD-12.1-RELEASE-amd64-dvd1.iso>
> 0%[ ] 19.05M 947KB/s eta
79m 18s
>
>
> % wlandebug +rate
> $ dmesg
> wlan0: [c0:05:c2:57:8d:69] AMRR: current rate 6, txcnt=11, retrycnt=6
> wlan0: [c0:05:c2:57:8d:69] AMRR decreasing rate 5 (txcnt=11
retrycnt=6)
> wlan0: [c0:05:c2:57:8d:69] AMRR: current rate 5, txcnt=36, retrycnt=1
> wlan0: [c0:05:c2:57:8d:69] AMRR increasing rate 6 (txcnt=36
retrycnt=1)
> wlan0: [c0:05:c2:57:8d:69] AMRR: current rate 6, txcnt=37, retrycnt=7
> wlan0: [c0:05:c2:57:8d:69] AMRR: current rate 6, txcnt=36, retrycnt=9
> wlan0: [c0:05:c2:57:8d:69] AMRR: current rate 6, txcnt=36, retrycnt=2
> wlan0: [c0:05:c2:57:8d:69] AMRR increasing rate 7 (txcnt=36
retrycnt=2)
> wlan0: [c0:05:c2:57:8d:69] AMRR: current rate 7, txcnt=36, retrycnt=5
> wlan0: [c0:05:c2:57:8d:69] AMRR: current rate 7, txcnt=36, retrycnt=5
> wlan0: [c0:05:c2:57:8d:69] AMRR: current rate 7, txcnt=37,
retrycnt=12
> wlan0: [c0:05:c2:57:8d:69] AMRR: current rate 7, txcnt=36, retrycnt=7
> wlan0: [c0:05:c2:57:8d:69] AMRR: current rate 7, txcnt=36,
retrycnt=10
>
> As you can see the MCS rate is being set by wlan_amrr to MCS 6 and
7, but the actual real-world download rate
> remains firmly stuck at around ~900KB/sec (!)
>
> Please could someone with knowledge of the FreebSD wifi stack help
diagnose this problem with me?
>
>
> hi!
>
> You can experiment with limiting the unicast rate - eg ifconfig wlan0
ucastrate 3 for MCS3 when it's in 11n mode.
>
> AMRR isn't the best at all at 802.11n rate selection. It may just be
over-estimating how great the channel is
behaving.
>
> However, that's just the transmit rate control. The remote end (ie the
sender) is making choices on what rate to use
> when transmitting to you. So let's see if we can first limit bad choices
(and thus taking up too much airtime)
> transmitting data BACK, and then we can figure out what's up with
download speeds.
>
>
>
> -adrian
>
Hi Adrian, thanks for your time and the explanation, much appreciated!
I tried setting ucastrate 3 and it made no difference to the download rate;
% ifconfig wlan0
wlan0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
ether 74:da:38:8b:e1:10
inet 192.168.0.12 netmask 0xffffff00 broadcast 192.168.0.255
groups: wlan
ssid VM5909357 channel 6 (2437 MHz 11g ht/20) bssid
c0:05:c2:57:8d:69
regdomain ETSI country GB authmode WPA2/802.11i privacy ON
deftxkey UNDEF AES-CCM 2:128-bit AES-CCM 3:128-bit txpower 30
bmiss 7
ucastrate 3 scanvalid 60 protmode CTS ht20 ampdulimit 64k
ampdudensity 8 shortgi -stbc -ldpc wme roaming MANUAL
media: IEEE 802.11 Wireless Ethernet MCS mode 11ng
status: associated
nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
% wget
https://download.freebsd.org/ftp/releases/amd64/amd64/ISO-IMAGES/12.1/FreeBSD-12.1-RELEASE-amd64-dvd1.iso
FreeBSD-12.1-RELEASE-amd64-dvd1.iso
<https://download.freebsd.org/ftp/releases/amd64/amd64/ISO-IMAGES/12.1/FreeBSD-12.1-RELEASE-amd64-dvd1.isoFreeBSD-12.1-RELEASE-amd64-dvd1.iso>.
0%[ ] 8.87M 806KB/s eta 81m 35s
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