It's hard to know what's going on unless you've tell us more about what's going on in the ".. do something" part. How do you know your conditional test (which your additions mention) isn't getting executed at all instead of just failing?

Try putting a print in there or something that is guaranteed to execute:

my $entered;
while(1) {
   print "Entered while loop\n" unless $entered++;
   # get input, read file, read socket, or whatever here
   #  ...
   if ( $test ) {
     #...
     last;
   }
   sleep(10);
}
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HTH

I mistrust all systematizers and avoid them. The will to a system shows a lack of integrity -- F. Nietzsche