Use ulimit or sysconf to give better scheduling priority to pi.

[rjt]

There is a long delay in starting the app.

ulimit -a and sysconf are ways to configure how much scheduling priority a normal user can have. Configure this in some /etc/ somewhere so that sudo is not required
each time.

ulimit -a will tell you that real-time priority is 95, so i have to wonder if that is not a negative number or is it the opposite of nice numbering.
Must use help ulimit not man ulimit.
ulimit -e indicates the maximum nice scheduling priority for user pi is 0.

nice priority values are reverse priority or the lower numbers have higher priority upto a maximum priority of negative twenty -20.