I have been experimenting with reducing jitter on a Raspberry Pi with the Preempt RT patch. The one thing I found that seemed to help was to set the CodeSys process to a nice level of -20. My test is not very scientific, but enough to see results. I have a program with 5 tasks and they are all set to free floating processor core use. My before and after jitter results:
Before -> After
129 -> 95
157 -> 117
154 -> 66
102 -> 62
521 -> 147
So my question is whether changing the nice value could have other side effects?
This is the method I used to change the CodeSys nice value:
Connect using SSH
cd /etc/init.d
sudo nano codesyscontrol
insert the "--nicelevel -20" into the following line :
I have been experimenting with reducing jitter on a Raspberry Pi with the Preempt RT patch. The one thing I found that seemed to help was to set the CodeSys process to a nice level of -20. My test is not very scientific, but enough to see results. I have a program with 5 tasks and they are all set to free floating processor core use. My before and after jitter results:
Before -> After
129 -> 95
157 -> 117
154 -> 66
102 -> 62
521 -> 147
So my question is whether changing the nice value could have other side effects?
This is the method I used to change the CodeSys nice value:
Connect using SSH
cd /etc/init.d
sudo nano codesyscontrol
insert the "--nicelevel -20" into the following line :
start-stop-daemon --start --background --make-pidfile --pidfile $PIDFILE --nicelevel -20 --chd$
reboot
Hi,
which jitter do you see , before you start changing anything?
BR
Edwin
These are the values before and after changes:
Before -> After
129 -> 95
157 -> 117
154 -> 66
102 -> 62
521 -> 147
This was only a short term test over a few hours so it may not be very accurate.