Did you try sniffing the traffic with tcpdump perhaps? You might want to do tcpdump -w x.pcap -c 20000 -s 128 -ni wlan0 (or eth0 on one of the endpoints, or even both). You can then run `tcptrace` on the pcap to see some statistics (perhaps something will stand out; I'm not an expert at reading these yet) or open it up with wireshark and inspect it interactively.
One time I had a very bizarre checksum corruption going on that I discovered upon opening a dump in wireshark and it was causing a lot of re-transmissions reducing performance a lot. You might want to see "ifstat" on the endpoints as well to see if/how it relates to the performance numbers iperf reports. Out of curiosity, what is RTT on an idle connection between your test endpoints? Michał On 22 April 2016 at 18:02, Iñaki Pascual <[email protected]> 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. > > 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 >>> [email protected] >>> http://lists.infradead.org/mailman/listinfo/ath10k >> >> >> > > > _______________________________________________ > ath10k mailing list > [email protected] > http://lists.infradead.org/mailman/listinfo/ath10k _______________________________________________ ath10k mailing list [email protected] http://lists.infradead.org/mailman/listinfo/ath10k
