We have monitoring scripts that need to be run every second. The scripts execution takes longer than a second, but that is not a problem.

So we have need a function that would run the script every second. The interval must be as precise as possible. I know that the preciseness depends on CPU, RAM, CMOS etc. I don’t care about these.

Currently, we use a script, let’s call it negative_timer. It works quite precisely, but the Time::HiRes::sleep from time to time complains that negative time not invented yet. A second using this script is in average about 0.000000676723442 less than a real second.

The problem is that the negative_timer substracts a second from a $max value. Sometimes the NTP kicks in and it makes the trouble. We don’t case if a second would be longer/shorter when the NTP updates the time.

Actually, we don’t need any $max value, as we run the monitoring script indefinitely (i.e. until seldom reboot or maintaince).

Could anyone help me out in this?

Thank you in advance.

The negative_timer script:

use strict;
use warnings;
use Time::HiRes qw/time sleep/;

sub negative_timer {
    my $max = $_[0];
    my @time_test;
    my $start = time();
    for (my $i = 0; $i < $max; $i++) {
        $start += 1;
        sleep $start - time();
        $time_test[$i] = time();
    }
    return @time_test;
}

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In reply to The most precise second (timer) by tukusejssirs

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