iwn: Intel Centrino 6205 bad 11n performance

[Adrian Chadd]

Please file a PR. I may end up getting around to it.

I don't know whether it's 11n TX or 11n RX, but we should really debug it.


-a


On 23 August 2014 12:19, Johannes Dieterich <dieterich.joh at gmail.com> wrote:
> Dear Adrian
>
> thanks a lot for the suggestion! Removing ht indeed improves the throughput
> to 1.7 MB/s. Still far from the maximum of my uplink but sufficient for the
> time being and much improved.
>
> Concerning the non-existing maintainer: does it in this case even make sense
> to file a PR?
>
> Given how common the Intel WLAN NICs (unfortunately) are and how some
> notebooks have white lists making a change to e.g. ath impossible, it is a
> real bummer that nobody maintains it. Thanks for your work on ath, btw,
> those NICs are working great nowadays!
>
> Thanks again for the help!
>
> Johannes
>
>
> On Wed, Aug 20, 2014 at 12:30 AM, Adrian Chadd <adrian at freebsd.org> wrote:
>>
>> Hi,
>>
>> You can try disabling 11n (ifconfig -ht) but besides that, there's no
>> real iwn maintainer or anyone who wants to get really nitty gritty
>> into what the driver is doing. So until that happens, I think we're
>> short of luck. :(
>>
>>
>> -a
>>
>>
>> On 19 August 2014 12:53, Johannes Dieterich <dieterich.joh at gmail.com>
>> wrote:
>> > Dear all,
>> >
>> > I have a Intel Centrino Advanced-N 6205 WLAN NIC in my Thinkpad using
>> > iwn.
>> >
>> > iwn0 at pci0:3:0:0:    class=0x028000 card=0x13118086 chip=0x00858086
>> > rev=0x34
>> > hdr=0x00
>> >     vendor     = 'Intel Corporation'
>> >     device     = 'Centrino Advanced-N 6205 [Taylor Peak]'
>> >     class      = network
>> >
>> > Unfortunately, I only get a rather bad speed using CURRENT (r270098) out
>> > of
>> > the chip. It is connected to an 11n (on the 2.4 GHz band) network:
>> >
>> > wlan0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu
>> > 1500
>> >     nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>> >     media: IEEE 802.11 Wireless Ethernet MCS mode 11ng
>> >     status: associated
>> >     ssid XXXXX channel 4 (2427 MHz 11g ht/20) bssid XXXXXXXXXX
>> >     country US authmode WPA2/802.11i privacy ON deftxkey UNDEF
>> >     TKIP 2:128-bit txpower 15 bmiss 10 scanvalid 60 bgscan bgscanintvl
>> > 300
>> >     bgscanidle 250 roam:rssi 7 roam:rate 64 protmode CTS ampdulimit 64k
>> >     ampdudensity 8 -amsdutx amsdurx shortgi wme roaming MANUAL
>> >
>> > I get a maximum of 900 KB/s of throughput (both in/out, approximated by
>> > copying a large file using scp), within the network and to the outside
>> > world. Running SuSE Linux on the notebook allows me to easily saturate
>> > my
>> > uplink at > 3MB/s, didn't then further check within the network. I get
>> > no
>> > log messages on FBSD from iwn and I am not located in a particularly
>> > noisy
>> > neighborhood.
>> >
>> > The only performance issue I can find with this chip is one old report
>> > on
>> > Ubuntu (http://ubuntuforums.org/showthread.php?t=1949571), where the 11n
>> > seemed to be the culprit in the driver/firmware. Could this be an issue
>> > for
>> > us as well (firmware problem?)?
>> >
>> > As my workhorse is FreeBSD, I'd love to fix this issue. How can I
>> > further
>> > debug this issue and/or provide more data? I know that the status of iwn
>> > in
>> > FBSD is difficult ATM but maybe there is hope?
>> >
>> > Best
>> >
>> > Johannes
>> > _______________________________________________
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>
>