Am 7. August 2016 13:41:04 MESZ, schrieb Arend van Spriel <arend.vanspriel@xxxxxxxxxxxx>:
>On 06-08-16 16:12, Jörg Krause wrote:
>> Hi all,
>
>A bit weird email format making it a bit hard to determine where your
>last reply starts...
Sorry for my bad mobile mail client. I hope this one can handle in line comments.
>
>> On Fr, 2016-08-05 at 17:56 -0700, Franky Lin wrote:
>>
>> On Fri, Aug 5, 2016 at 2:29 PM, Jörg Krause <joerg.krause@xxxxxxxxxxx
>> cks>
>> wrote:
>>
>>
>>
>>
>>
>> Am 5. August 2016 23:01:10 MESZ, schrieb Arend Van Spriel <
>> arend.vanspriel@xxxxxxxxxxxx>:
>>
>>
>> Op 5 aug. 2016 22:46 schreef "Jörg Krause"
>> <joerg.krause@embedded.rocks>:
>>
>>
>>
>> Hi,
>>
>> I'm using a custom ARM board with an BCM43362 wifi chip from
>>
>> Broadcom.
>>
>>
>> The wifi chip is attached via SDIO to the controller with a
>> clock of
>> 48MHz. Linux kernel version is 4.7.
>>
>> When measuring the network bandwidth with iperf3 I get a
>> bandwith of
>> only around 5 Mbps. I found a similar thread at the Broadcom
>>
>> community
>>
>>
>> [1] where the test was done with a M4 CPU + BCM43362 and an
>> average
>> result of 3.3 Mbps.
>>
>> Interestingly, a BCM43362 Wi-Fi Dev Kit [2] notes a TCP data
>>
>> throughput
>>
>>
>> greater than 20 Mbps.
>>
>> Why is the throughput I measured much lower? Note that I
>> measured
>> several times with almost no neighbor devices or networks.
>>
>> This is a test sample measured with iperf3:
>>
>> $ iperf3 -c 192.168.2.1 -i 1 -t 10
>> Connecting to host 192.168.2.1, port 5201
>> [ 4] local 192.168.2.155 port 36442 connected to
>> 192.168.2.1
>>
>> port
>>
>>
>> 5201
>> [ ID]
>> Interval Transfer Bandwidth Retr Cwnd
>> [ 4] 0.00-1.00 sec 615 KBytes 5.04
>> Mbits/sec 0 56.6
>> KBytes
>> [ 4] 1.00-2.00 sec 622 KBytes 5.10
>> Mbits/sec 0 84.8
>> KBytes
>> [ 4] 2.00-3.00 sec 625 KBytes 5.12
>> Mbits/sec 0 113
>> KBytes
>> [ 4] 3.00-4.00 sec 571 KBytes 4.68
>> Mbits/sec 0 140
>> KBytes
>> [ 4] 4.00-5.00 sec 594 KBytes 4.87
>> Mbits/sec 0 167
>> KBytes
>> [ 4] 5.00-6.00 sec 628 KBytes 5.14
>> Mbits/sec 0 195
>> KBytes
>> [ 4] 6.00-7.00 sec 619 KBytes 5.07
>> Mbits/sec 0 202
>> KBytes
>> [ 4] 7.00-8.00 sec 608 KBytes 4.98
>> Mbits/sec 0 202
>> KBytes
>> [ 4] 8.00-9.00 sec 602 KBytes 4.93
>> Mbits/sec 0 202
>> KBytes
>> [ 4] 9.00-10.00 sec 537 KBytes 4.40
>> Mbits/sec 0 202
>> KBytes
>> - - - - - - - - - - - - - - - - - - - - - - - - -
>> [ ID] Interval Transfer Bandwidth Retr
>> [ 4] 0.00-10.00 sec 5.88 MBytes 4.93
>> Mbits/sec 0 sender
>> [ 4] 0.00-10.00 sec 5.68 MBytes 4.76
>> Mbits/sec receiver
>>
>>
>> Not overly familiar with iperf3. Do these lines mean you are
>> doing
>> bidirectional test, ie. upstream and downstream at the same time.
>> Another
>> thing affecting tput could be power-save.
>>
>>
>> No, iperf3 does not support bidrectional test. Power-save is turned
>> off.
>>
>> What does iw link say?
>>
>
>but I guess it starts here!
>
>> I compared the results with a Cubietruck I have:
>>
>> # iperf3 -s
>> -----------------------------------------------------------
>> Server listening on 5201
>> -----------------------------------------------------------
>> Accepted connection from 192.168.178.46, port 42906
>> [ 5] local 192.168.178.38 port 5201 connected to 192.168.178.46 port
>> 42908
>> [ ID] Interval Transfer Bandwidth
>> [ 5] 0.00-1.00 sec 2.29 MBytes 19.2 Mbits/sec
>
>> [ 5] 1.00-2.00 sec 2.21 MBytes 18.5 Mbits/sec
>
>> [ 5] 2.00-3.00 sec 2.17 MBytes 18.2 Mbits/sec
>
>> [ 5] 3.00-4.00 sec 2.09 MBytes 17.6 Mbits/sec
>
>> [ 5] 4.00-5.00 sec 2.20 MBytes 18.5 Mbits/sec
>
>> [ 5] 5.00-6.00 sec 2.64 MBytes 22.1 Mbits/sec
>
>> [ 5] 6.00-7.00 sec 2.67 MBytes 22.4 Mbits/sec
>
>> [ 5] 7.00-8.00 sec 2.62 MBytes 22.0 Mbits/sec
>
>> [ 5] 8.00-9.00 sec 2.35 MBytes 19.8 Mbits/sec
>
>> [ 5] 9.00-10.00 sec 2.30 MBytes 19.3 Mbits/sec
>
>> [ 5] 10.00-10.03 sec 83.4 KBytes 23.5 Mbits/sec
>
>> - - - - - - - - - - - - - - - - - - - - - - - - -
>> [ ID] Interval Transfer Bandwidth Retr
>> [ 5] 0.00-10.03 sec 23.9 MBytes 20.0
>> Mbits/sec 0 sender
>> [ 5] 0.00-10.03 sec 23.6 MBytes 19.8
>> Mbits/sec receiver
>>
>> # iw dev wlan0 link
>> Connected to xx:xx:xx:xx:xx (on wlan0)
>> SSID: xxx
>> freq: 2437
>> tx bitrate: 65.0 MBit/s
>>
>> bss flags: short-preamble short-slot-time
>> dtim period: 1
>> beacon int: 100
>
>Too bad RSSI is not in the output above. That may be due to a
>regression
>in our driver which has been fixed by commit 94abd778a7bb ("brcmfmac:
>add fallback for devices that do not report per-chain values").
>However,
>the tx bitrate seems within the same range as the other platform.
>
>> The Cubietruck works also with the brcmfmac driver.
>>
>> May it depend on the NVRAM file?
>
>Not sure. Can you tell me a bit more about the custom ARM board. Does
>it
>use the same wifi module as Cubietruck, ie. the AMPAK AP6210? If you
>can
>make a wireshark sniff we can check the actual bitrate and medium
>density in terms of packets. Another thing to look at is the SDIO host
>controller. In brcmf_sdiod_sgtable_alloc() some key values are used
>from
>the host controller. It only logs the number of entries of the
>scatter-gather table, but could you add the other values in this
>function that are used to determine the number of entries.
Many thanks for your conclusions! I am on vacation right now and I will investigate this issue further when I am back.
Best regards,
Jörg Krause
--
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
