[etherlab-users] Linux Light ethercat slave - propagation delay benchmarks

[Raz]

Linux light ethercat slave
(https://sourceforge.net/p/ecslave/wiki/Howto/)  is an open source
kernel module implementing a light ethercat slave.
Currently i am testing its responsiveness in various hardware configurations.
Here are some propagation Delay benchmarks.

My setup is as constructed from 3 machines, master + 2 slaves.
The master is an etherlab 1.5.1 on a intel core i5.

test 1

slave 0: Laptop . intel dual core i3. Input interface is realtek interface.
Output interface is usbnet adapter.

slave 1: laptop. intel dual core Pentium. input interface is realtek. 8139

Propagation delay: 250us

test 2

Slave 0 : vortex + two network interfaces.
Input interface realtek 8139
Output interface is RDC r6040

slave 1: Raspberry pi. Interface is usb based. drive is smsc95xx.ko

Propagation delay:208us

test 3

Slave 0 : vortex + two network interfaces.
Input interface : realtek 8139
Output interface : RDC r6040

slave 1: laptop. intel dual core Pentium. input interface is realtek. 8139

Propagation delay: 53us

Conclusions & action items

1. USB to NET is worst for performance. comparing test 1 to test 3
proves that using ethernet over usb network devices is extremely slow
2. Test a home-router ( d-link, edimax) delays. I will be needing to
adopt etherlab to work over udp as well as ecslave.


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