What amount of processing time is too much for a CPM customization configured to run synchronously?

Environment

Process Designer, Custom Process Model (CPM) / Service Process Model (SPM)
All product versions

Issue:

In terms of the length of time to process the script, how to I know if my synchronous CPM customization is safe to configure to run synchronously?

Resolution:

Synchronous CPMs have a five second time limit. However, CPM scripts found to ever take longer than two seconds to run are generally at risk of overreaching the five second time limit in future runs.

Length of CPM execution can be determined through the implementation of custom logging, which is a recommended best practice. Consider changing any synchronous CPMs to asynchronous if logging shows even occasional processing/execution time of over two seconds.