#linuxcnc-devel Logs

Dec 11 2018

#linuxcnc-devel Calendar

10:50 AM crazyben: rmu, Hello - I tried the to add #include "rtai_mutex" below #include "rtapi_app.h" and build lcec. This did solve the issue with lcec. Thank you very much!! :-)
10:53 AM rmu: yw
10:53 AM rmu: it would be nice if you could communicate this upstream
10:53 AM crazyben: rmu: To get ethercat (build with ec-debianize), I had to add "allow-hotplug eth0 iface eth0 inet dhcp" to my network settings
10:55 AM crazyben: rmu: my plan is to do so. Could you tell me what may be "good" Jitter / Latency-Times on a PREEMT-Kernel? AT the moment, I have 178.000 (Servo Thread) and 32.000 (Base Thread). These values look too high for me
10:57 AM rmu: you need only the "slow" 1kHz thread. I get max jitter of about 100µs on a raspberry pi 3, a properly configured PC should be (much) better
10:59 AM crazyben: This is a HP-Laptop with Core i5 and 8GB RAM
11:00 AM crazyben: Don't know how old this is, but are these still realistic references on this page?
11:00 AM crazyben: http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Latency-Test
11:01 AM rmu: historically laptops were not the best joice for linuxcnc because of somewhat unpredictable power and thermal management causing latencies. don't know about situation now. i would reserve the ethernet interface for ethercat traffic.
11:03 AM crazyben: rmu, whats the exact meaning of you last sentence? - Sorry, I am not a native speaker
11:04 AM rmu: german?
11:04 AM crazyben: Austrian?
11:04 AM rmu: s/joice/choice/
11:04 AM rmu: oh, nice, i'm from linz ;)
11:04 AM crazyben: Karlsruhe :-)
11:06 AM rmu: also auf deutsch: Notebooks sind nicht unbedingt die beste Wahl für linuxcnc, weil power- und temperatur-management dazwischenfunken können. Ethernet-Interface für das Realtime-Zeug sollte für nichts anderes verwendet werden.
11:10 AM crazyben: Than I already got it. Sure - I am using the LAN-Interface for Ethercat only. Due to the fact that the Ethercat driver will be loaded while Starting LinuxCNC, it seems to be necessary to configure the interface with "Allow-hotplug". Otherwise (at least on this creepy e1000e chipset and debian 9)
11:12 AM crazyben: won't start my interface up (Ethercat that protocoll seems to remain then unloaded). If I fon't configure the interface as described, I have to manually start up interface using "if up eth0" manually..
11:12 AM pcw_home: crazyben: you will get more realistic latency figures if test with servo thread only (latency-histogram --nobase --sbinsize 1000)
11:14 AM crazyben: rmu: regarding the performance, I am running now on powersupply again (has disconnected itselv - yes, my desk is a nightmare at the moment). running "while true ; do echo "nothing" > /dev/null ; done" I am getting now 175.000ns@Servo and 40.500ns@Base
11:15 AM rmu: crazyben: i know nothing about ethercat, it seems to include it's own ethernet drivers.
11:15 AM rmu: crazyben: try opening a webbrowser and a number of tabs, some opengl app, start a large build, and monitor latency
11:15 AM rmu: with latency-histogram --nobase --sbinsize 1000
11:16 AM rmu: you don't need the fast base thread
11:18 AM crazyben: rmu, indeed - I worked for a company within automation sector a couple years ago. we used the ethercat components to connect field componts of chemical and metal (steel) - industry, as they give the customer better interchange and scaleability (just add a new module if it is needed or remove)
11:19 AM rmu: i need to go. will check back later
11:19 AM crazyben: rmu, how many gears do we want?
11:21 AM crazyben: rmu, I have now 4 glxgears and the "while true ; do echo "nothing" > /dev/null ; done" in the background running.
12:11 PM crazyben: rmu: I was able to reduce jitter values now down 11145@ServoThread and 12324@Base Thread while running 8glxgears and 4 "gzip -c /dev/urandom > /dev/null"
12:14 PM rmu: nochmal: der base thread ist nicht notwendig wenn der servo am ethernet hängt