Re: low TCP throughput with 80MHz channel width

From: Ben Greear <greearb@candelatech.com>
To: "Iñaki Pascual" <ipascual@cttc.cat>, ath10k@lists.infradead.org
Subject: Re: low TCP throughput with 80MHz channel width
Date: Fri, 22 Apr 2016 09:16:39 -0700	[thread overview]
Message-ID: <571A4E67.7090308@candelatech.com> (raw)
In-Reply-To: <571A4D22.7060704@cttc.cat>

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@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@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@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@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@lists.infradead.org
>>>>> http://lists.infradead.org/mailman/listinfo/ath10k
>>>>
>>>>
>>>
>>
>>
>

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

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