I didn't see anyone post about this warning while using the debugger (sorry if I missed it). You can change the default of 100 in the debugger very easily for testing/troubleshooting by setting $DB::deep...

Default:

$ perl -d rec.pl

main::(rec.pl:10):      f(1);

  DB<1> c
main::f(rec.pl:6):          $_[0] unless $_[0] % 10000;

100 levels deep in subroutine calls!
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Set to 500:

$ perl -d rec.pl

main::(rec.pl:10):      f(1);

  DB<1> $DB::deep = 500

  DB<2> c
main::f(rec.pl:6):          $_[0] unless $_[0] % 10000;

500 levels deep in subroutine calls!
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