low TCP throughput with 80MHz channel width

Iñaki Pascual ipascual at cttc.cat
Fri Apr 22 09:44:18 PDT 2016


Thanks for your help Ben.

I think we will go for kernel 4.4 and the latest firmware relase.

Regarding the firmware, should we try the CT-10.2 or it is not stable 
enough?

Bests,

Iñaki



On 22/04/16 18:16, Ben Greear wrote:
> On 04/22/2016 09:11 AM, Iñaki Pascual wrote:
>> We are using kernel 4.2 with CandelaTech firmware 
>> 10.1.467-ct-com-full-014-96d543
>
> Maybe try rls 15 or beta-16 CT 10.1 firmware?
>
> And, we found too much instability in 4.2 kernel.  We suggest 4.0 or 4.4,
> though I am not aware of any throughput related bugs aside from the CUBIC
> congestion control issue.
>
> You might also try our 3.17 kernel since CUBIC worked in that kernel...
>
> Thanks,
> Ben
>
>
>>
>> monet at sc227:~$ ethtool -i wlan2
>> driver: ath10k_pci
>> version: 4.2.0+
>> firmware-version: 10.1.467-ct-com-full-014-96d543
>> bus-info: 0000:0b:00.0
>> supports-statistics: yes
>> supports-test: no
>> supports-eeprom-access: no
>> supports-register-dump: no
>> supports-priv-flags: no
>>
>> Thanks,
>>
>> Iñaki
>>
>> On 22/04/16 18:06, Ben Greear wrote:
>>> On 04/22/2016 09:02 AM, Iñaki Pascual wrote:
>>>
>>>> Thanks for the tip Ben. We have moved to 'reno' and tried several 
>>>> window sizes but we are still on max. 35 Mbps which is too low.
>>>>
>>>
>>> What firmware and kernel are you using?
>>>
>>> Thanks,
>>> Ben
>>>
>>>> Bests,
>>>>
>>>> Iñaki
>>>>
>>>> On 22/04/16 17:40, Ben Greear wrote:
>>>>> Use 'reno' instead of cubic TCP congestion control, cubic is 
>>>>> broken with ath10k.
>>>>>
>>>>> Thanks,
>>>>> Ben
>>>>>
>>>>> On 04/22/2016 08:32 AM, Iñaki Pascual wrote:
>>>>>> Hi everyone,
>>>>>>
>>>>>> we have configured two boxes with 802.11ac NICs to work in 
>>>>>> channel 48 (5240 MHz), ad-hoc mode, 80MHz channel width.
>>>>>> For UDP traffic we get 300 Mbps bandwith but for TCP we are 
>>>>>> around 30 Mbps.
>>>>>>
>>>>>> We have tried other channels with similar results.
>>>>>> Throughput for 20 and 40 MHz channel width are ok (20MHz: TCP 
>>>>>> 21Mbps, UDP 27Mbps, 40MHz: TCP 82Mbps, UDP 144Mbps).
>>>>>>
>>>>>> Testing with iperf we have also tried different congestion 
>>>>>> windows with no or low improvements.
>>>>>>
>>>>>> Below are config details and the sequence of commands we are 
>>>>>> using to configure the interface.
>>>>>>
>>>>>> Any ideas on what we may be doing wrong?
>>>>>>
>>>>>> Bests,
>>>>>>
>>>>>> Iñaki
>>>>>>
>>>>>> iw outputs:
>>>>>>
>>>>>> root at sc227:/home/monet# iw wlan2 info
>>>>>> Interface wlan2
>>>>>>      ifindex 6
>>>>>>      wdev 0x200000001
>>>>>>      addr 04:f0:21:18:26:a2
>>>>>>      ssid SC226SC227
>>>>>>      type IBSS
>>>>>>      wiphy 2
>>>>>>      channel 48 (5240 MHz), width: 80 MHz, center1: 5210 MHz
>>>>>>
>>>>>> root at sc227:/home/monet# iw wlan2 station dump
>>>>>> Station 04:f0:21:18:26:a8 (on wlan2)
>>>>>>      inactive time:    86 ms
>>>>>>      rx bytes:    467732521
>>>>>>      rx packets:    364249
>>>>>>      tx bytes:    1394558
>>>>>>      tx packets:    16200
>>>>>>      tx retries:    0
>>>>>>      tx failed:    0
>>>>>>      signal:      -51 dBm
>>>>>>      signal avg:    -51 dBm
>>>>>>      tx bitrate:    351.0 MBit/s VHT-MCS 4 80MHz VHT-NSS 2
>>>>>>      rx bitrate:    526.5 MBit/s VHT-MCS 4 80MHz VHT-NSS 3
>>>>>>      authorized:    yes
>>>>>>      authenticated:    yes
>>>>>>      preamble:    long
>>>>>>      WMM/WME:    yes
>>>>>>      MFP:        no
>>>>>>      TDLS peer:    no
>>>>>>      connected time:    3169 seconds
>>>>>>
>>>>>>
>>>>>> config commands:
>>>>>>
>>>>>> ifconfig wlan2 down
>>>>>> iw wlan2 set type ibss
>>>>>> ifconfig wlan2 up
>>>>>> ifconfig wlan2 10.2.1.7 netmask 255.255.255.0
>>>>>> iw wlan2 ibss join SC226SC227 5240 80MHz
>>>>>>
>>>>>> iperf:
>>>>>> root at sc227:/home/monet# iperf -c 10.2.1.6
>>>>>> ------------------------------------------------------------
>>>>>> Client connecting to 10.2.1.6, TCP port 5001
>>>>>> TCP window size: 85.0 KByte (default)
>>>>>> ------------------------------------------------------------
>>>>>> [  3] local 10.2.1.7 port 48548 connected with 10.2.1.6 port 5001
>>>>>> [ ID] Interval       Transfer     Bandwidth
>>>>>> [  3]  0.0-10.0 sec  33.1 MBytes  27.7 Mbits/sec
>>>>>>
>>>>>> _______________________________________________
>>>>>> ath10k mailing list
>>>>>> ath10k at lists.infradead.org
>>>>>> http://lists.infradead.org/mailman/listinfo/ath10k
>>>>>
>>>>>
>>>>
>>>
>>>
>>
>
>




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