On RT it's possible to have 2 Differents Priority VI call same Sub vi

Question

    As NI documentation precise, I implement  2 Vi's for my RT application
the first the highest priority  handle all the critical tasks
the second manage the non critical and the dialog with a server
All works enough well,
But after some modifications i notice a larger jitter (With my scope)
and i don' t find the reason.
I have several sub vi's use in the two vi.
Is is it the reason for my greater jitter ??
And if yes : have i to set theses subvi to reentrant or else actions ?
Thanks for your help.
Christophe

Answer 1

Hello Christophe,
you are absolute right with your assumption: Having non-reentrant VIs in both, the high-priority and the lower-priority VI is a so-called shared resource. (This term you will also find in the RT documentation.)
A higher-priority VI cannot execute a shared VI as long as a lower-priority VI currently executes this shared VI (This is only true if the shared VI is not reentrant). Making your shared VI(s) reentrant will avoid this and decrease the jitter of your high-priority VI. (Verify that each shared VI is a candidate for a reentrant VI.)
Regards, Guenter