If you use Time::HiRes and export its sleep, you can sleep in fractional seconds. A 10ms sleep would work like this:

#!/usr/bin/perl -w
use strict;
use Time::HiRes ('sleep');

print STDERR 'Pausing:';
sleep(0.01); ## Sleep for 1/100th of a second (10ms)
print STDERR 'done',"\n";
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It's worth mentioning that this isn't guaranteed to be ultra-accurate.