Takamoto:

To test your code, I added this to the end:

sub tprint {
    my $t = time;
    print "$t: ", shift, "\n";
}

sub getResultsAPI {
    my ($name, $doze_time) = @_;
    tprint "API_$name: dozing for ${doze_time}s";
    sleep $doze_time;
    tprint "API_$name: done";
}


sub getResultsAPI_1 { getResultsAPI(1, 12) }
sub getResultsAPI_2 { getResultsAPI(2, 22) }
sub getResultsAPI_3 { getResultsAPI(3, 16) }
sub getResultsAPI_4 { getResultsAPI(4, 5) }
sub getResultsAPI_5 { getResultsAPI(5, 11) }
sub getResultsAPI_6 { getResultsAPI(6, 7) }
[download]

And it seemed to do what you'd expect:

$ perl pm_11107400.pl
1570989189: API_1: dozing for 12s
1570989189: API_2: dozing for 22s
1570989189: API_3: dozing for 16s
1570989189: API_4: dozing for 5s
1570989189: API_5: dozing for 11s
1570989194: API_4: done
1570989200: API_5: done
1570989201: API_1: done
1570989205: API_3: done
1570989211: API_2: done
[download]

Of course, if your APIs contend with each other for resources (such as hitting the hard drive a lot), you may not save much time. If they run well in parallel as the simple sleep timers do in the case I tried, you can save much more. Make sure you look at what your different APIs do to see if they conflict with each other. Bundling IO-heavy operations with CPU-heavy operations tends to work well to save you time. Similarly, you can *lose* time if you have processes always contending for the same resources.

Note that you have a minor bug, though, in that you never run API_6. I'm assuming the bug was introduced by your simplification of the test code.

...roboticus

When your only tool is a hammer, all problems look like your thumb.