Monitor cRIO CPU level

[wireties]

It runs vxWorks and VxWorks is an industrial real-time operating system. It does not run "VxWorks on Unix". VxWorks has a task-based profiler called 'spy'. I have not checked to see if FIRST/NI/WPI included it in the kernel image they gave us. If this feature is in the kernel you can see the spy output from the command line or from Workbench.

HTH

[Greg McKaskle]

spy and similar serial terminal tools will give you a performance dump.

If using LV, it is pretty easy to open the Tools>>RealTime>>Real Time System Monitor. Unfortunately, its default settings have lots of overhead, so hit the other tab and turn of VI state. On the original tab, turn on performance, either leave disk on or off, doesn't matter much. Now hit the start button and observe the chart.

Greg McKaskle

[Tom Line]

Thank you! We were looking at doing some additional and rather extensive image processing, and I wasn't sure how the CPU would hold up.

It there a threshold of CPU usage we should strive to stay below?

[Alan Anderson]

Originally Posted by Tom Line

It there a threshold of CPU usage we should strive to stay below?

Don't go over 100%.

Seriously, unused CPU cycles are of no value. There's no benefit to limiting yourself to only a fraction of the available processing power.

[AustinSchuh]

Originally Posted by Alan Anderson

Don't go over 100%.

Seriously, unused CPU cycles are of no value. There's no benefit to limiting yourself to only a fraction of the available processing power.

I'm not sure how good the vxWorks scheduler is, but wouldn't you want to leave a couple of percent left so that the processes that need to be responsive, like the one that talks to the DS, can be scheduled easier and on time?

[Mike Soukup]

Originally Posted by AustinSchuh

I'm not sure how good the vxWorks scheduler is, but wouldn't you want to leave a couple of percent left so that the processes that need to be responsive, like the one that talks to the DS, can be scheduled easier and on time?

VxWorks has an excellent scheduler. If the controller was designed properly (and I assume it was, I just haven't looked at the relative priorities of the tasks) the critical tasks that we rely on will all have appropriate priorities. VxWorks guarantees that if a higher priority task wants to run, it will run before a lower priority task.