Ignition 8.0.16 - Status/Tags/Groups Last duration

Ignition 8.0.16

On the gateway, in the Status/Tags/Groups:
Last duration has no unit and lots of value are 0.

The value are in milliseconds (or seconds) ? rounded ?

It’s all milliseconds, and the during a conversion from nanos to millis for groups that executed effectively instantly some precision is lost. Most tag types no longer contribute to group execution time any more.

But I have Driven tag group for tag expression with Last Duration = 0.
Executions count is incremented, so the expression is active, but the last duration value = 0
These expression execute runscript with quite long task so I supected that the value was not updated in that case…

Expression tags in 8 run in a thread pool and their execution time no longer contributes to the group execution.

I think we’ve discussed removing these measurements in 8 because they are effectively useless.

Ok I see, with System.currentTimeMillis() I can measure the time in the runscript.
In 7.9, I checked the Group’s Last Duration to check if the Rate was compatible with the execution time.

Don’t use System.currentTimeMillis() for durations. Use System.nanoTime() instead. It won’t go backwards on you, and is more precise, too.

Multiple thread are launched for the same Tag Group or one thread for one Tag group ?

All expression tags execute on one shared thread pool.