On Mi, 2016-08-24 at 20:35 +0200, Arend Van Spriel wrote:

On 22-8-2016 15:37, Jörg Krause wrote:

quoted

Hi all,

I am back from vacation and I'd like to do more investigations
about
this issue. Please see my comments below...

On Sun, 2016-08-07 at 13:41 +0200, Arend van Spriel wrote:

quoted

On 06-08-16 16:12, Jörg Krause wrote:

quoted

Hi all,

A bit weird email format making it a bit hard to determine where
your
last reply starts...

quoted

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@embed
ded.
ro
cks>
wrote:





Am 5. August 2016 23:01:10 MESZ, schrieb Arend Van Spriel <
arend.vanspriel@broadcom.com>:


Op 5 aug. 2016 22:46 schreef "Jörg Krause"
[off-list ref]:



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!

quoted

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.

quoted

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.

My board uses the BCM43362 chip solely (no Bluetooth) attached to
the
SDIO interface of a NXP i.MX28 processor.

I added some additional printk() to brcmf_sdiod_sgtable_alloc().
These
are the values printed after modprobe brcmfmac:

[    8.926657] sg_support=1
[    8.929440] max_blocks=511
[    8.932213] max_request_size=261632
[    8.935741] max_segment_count=52
[    8.939005] max_segment_size=65280
[    8.946095] nents=35

Thanks. That looks good.

quoted

Additionally I attached a xz compresses wireshark sniff while
running
iper3 between the BCM43362 running as in AP mode with iperf3 as a
server and a PC in station mode running iperf3 as a client.

Looking at the sniff it seems you captured on the ethernet side. That
does not give me any 802.11 specific info. Can you make a wireless
capture preferably without encryption.

You,re right! Sorry for this mistake. I did a re-capture on the
wireless side now.

Best regards
Jörg Krause