Date:   Tue, 5 Mar 2019 10:55:57 +0100
From:   Simon Huelck <simonmail@....de>
To:     Jose Abreu <jose.abreu@...opsys.com>,
        Sebastian Gottschall <s.gottschall@...media-net.de>,
        Jerome Brunet <jbrunet@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Cc:     linux-amlogic@...ts.infradead.org, Gpeppe.cavallaro@...com,
        alexandre.torgue@...com,
        Emiliano Ingrassia <ingrassia@...genesys.com>,
        netdev@...r.kernel.org
Subject: Re: stmmac / meson8b-dwmac

Hi guys,


1. i discovered something strange. when i never configure my external
VLAN interface UP ( firewall doesnt start, traffic shaper CAKE doesnt
start), my non duplex iperf bandwidth increases from 600MBits to 930.

2.  duplex isnt working, TX is totally starving RX, the total bandwidth
is 900MBits, whats going on there ?

3. i had a MTU issue ( was set to 1500, but due to VLANs etc 1450 would
be better ) but this didnt change performance
4. even when i up eth0.4, then i down eth0.4, then flush iptables and
shaper were never added, i drop to 600MBits ....

questions:
- why is duplex still not working even so the kernel says so ?
- why is TX totally starving RX, even so duplex is "on"
- when i flush all my iptable rules, and the traffic shaper, still im
bond to 600MBits ... very strange, someone got an idea ? upping eth0.4
is cutting the performance, even when other VLAN IFs like eth0.3,
eth0.2, eth0.5 are up and bridged ( eth0.4 isnt bridged somewhere )



my setup:

br-dmz          8000.7ef0fd9b157f       no              eth0.2
br-guest                8000.001f1fbbbd60       no              wlan0
br-iot          8000.7ef0fd9b157f       no              eth0.5
br-lan          8000.001f1fbbbd61       no              eth0.3
                                                        wlan0_1
                                                        wlan2

eth0.4 is my uplink

all the bridges are internally , eth0.4 is externally


C:\Users\Simon\Downloads\iperf3.6_64bit\iperf3.6_64bit>iperf3.exe -c
10.10.11.1 -i1
warning: Ignoring nonsense TCP MSS 0
Connecting to host 10.10.11.1, port 5201
[  5] local 10.10.11.100 port 52173 connected to 10.10.11.1 port 5201
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec   384 KBytes  3.14 Mbits/sec
[  5]   1.00-2.00   sec   384 KBytes  3.15 Mbits/sec
[  5]   2.00-3.00   sec  1.12 MBytes  9.44 Mbits/sec
[  5]   3.00-4.00   sec  2.00 MBytes  16.8 Mbits/sec
[  5]   4.00-5.00   sec  2.38 MBytes  19.9 Mbits/sec
[  5]   5.00-6.00   sec  3.12 MBytes  26.2 Mbits/sec
[  5]   6.00-7.00   sec  4.75 MBytes  39.8 Mbits/sec
[  5]   7.00-8.00   sec  68.4 MBytes   574 Mbits/sec
[  5]   8.00-9.00   sec   104 MBytes   875 Mbits/sec
[  5]   9.00-10.00  sec   105 MBytes   881 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.00  sec   292 MBytes   245 Mbits/sec                  sender
[  5]   0.00-10.04  sec   292 MBytes   244 Mbits/sec                 
receiver

iperf Done.


root@...oidc2:~# iperf3 -c 10.10.11.100 -i1
Connecting to host 10.10.11.100, port 5201
[  5] local 10.10.11.1 port 60022 connected to 10.10.11.100 port 5201
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec   112 MBytes   941 Mbits/sec    0    417 KBytes
[  5]   1.00-2.00   sec   113 MBytes   945 Mbits/sec    0    487 KBytes
[  5]   2.00-3.00   sec   112 MBytes   940 Mbits/sec    0    487 KBytes
[  5]   3.00-4.00   sec   112 MBytes   941 Mbits/sec    0    512 KBytes
[  5]   4.00-5.01   sec   109 MBytes   907 Mbits/sec    0    543 KBytes
[  5]   5.01-6.01   sec   109 MBytes   911 Mbits/sec    0    543 KBytes
[  5]   6.01-7.01   sec   108 MBytes   902 Mbits/sec    0    543 KBytes
[  5]   7.01-8.01   sec   108 MBytes   905 Mbits/sec    0    543 KBytes
[  5]   8.01-9.00   sec   106 MBytes   895 Mbits/sec    0    543 KBytes
[  5]   9.00-10.00  sec   106 MBytes   891 Mbits/sec    0    543 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  1.07 GBytes   918 Mbits/sec    0             sender
[  5]   0.00-10.04  sec  1.07 GBytes   915 Mbits/sec                 
receiver

--


Mar  5 09:46:03 localhost kernel: [  105.534204] meson8b-dwmac
c9410000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off

iperf Done.
root@...oidc2:~#




regards,
Simon

Am 01.03.2019 um 10:23 schrieb Jose Abreu:
> Hi Simon,
>
> On 2/27/2019 7:02 PM, Simon Huelck wrote:
>> Hi,
>>
>>
>> the thing is , that im not a stmmac developer. Yes , maybe i can bissect
>> it and yes you are lucky since im a C-developer since a long time for
>> embedded systems.
>>
>> The problem is that i dont understand the structure of stmmac and im not
>> aware of any documentation about the driver structure nor the underlying
>> ethernet hardware ( even though im used to ethernet hardware in embedded
>> environment ). So how shall i recognize the relevant change between
>> 4.14.29 and 5.0rc8 ?
>>
>>
>> Is it in the DTS/DTB, wrong hardware description ? Is it in the code ?
>> how is the duplex hardware working on this piece ?
>>
>> I can try to support you the best i can, but i have little chances to
>> analyze it myself. At which measurements / counters is it possible to
>> see that duplex is fully working ?  Why did even the non-duplex
>> bandwidth regress from 900MBits to 650 ? Why is that 650 MBits dividing
>> up to TX and RX in summary when doing duplex ? Why is TX not starving in
>> duplex but RX ?
>>
>> From my point of view should be the following things given:
>> - the non duplex bandwidth should be somewhere around 900MBits , the HW
>> is capable of that
>> - TX should not influence RX or vice versa in duplex
>> - the duplex bandwidth should be 900MBits in both directions ( maybe a
>> bit asymetric when buffers in both dirs are not same )
>>
>> I guess we need some profiling on stmmac and ( at least i need ) more
>> knowledge of the hardware and stmmac itself. Can someone point me to the
>> driver documentation, describing the functions in the code and the
>> structure ? How can i profile stmmac ( usually im using hardware / JTAG
>> debuggers at work, but here @home i got nothing like that )
>>
>> So how do we continue ?
> When I said bissect I was meaning GIT Bissect [1]. You shouldn't
> need any development background for this. You just have to start
> bissect, compile, test and check if commit is good or not.
>
> I'm not very familiar with this feature but I think you can
> bissect pretty fast if you say you just want stmmac commits,
> check ("Cutting down bisection by giving more parameters to
> bisect start") on previous link ... In your case it would be
> stmmac changes, dts, and phy.
>
> [1] https://git-scm.com/docs/git-bisect
>
> Thanks,
> Jose Miguel Abreu

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