You would use unsafe signals in a trading system
Have you gone totally mad?
Unsafe signals can hit at any time, and leave the Perl internals in an unknown, unsafe, unusable state. Then the unsafe signal handler proceeds to execute Perl code using those internals! A trading system is exactly the kind of high-stakes deployment where everything must be safe!
If you want a fast restart, then you should have a watchdog process outside the target, which can
kill it (with SIGKILL if necessary) and restart it. That way you're getting a fast response without putting yourself at risk for a big financial bath.
-- Chip Salzenberg, Free-Floating Agent of Chaos