low TCP throughput with 80MHz channel width

[Ben Greear]

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
>
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> ath10k at lists.infradead.org
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-- 
Ben Greear <greearb at candelatech.com>
Candela Technologies Inc  http://www.candelatech.com