kbensons.pl

use strict;
use warnings;
use threads;
use threads::shared;
use Time::HiRes qw/time/;
my @thread_times :shared;

sub workfunc {
 my $start = time();
 print "Thread ".threads::tid()." :: started at ".localtime()."\n";
 my $init = shift;
 for (1 .. 10_000_000) {
  $init += (($_%4)*($_%4)) / ($_%10+1);
 }
 my $runtime = time() - $start;
 { lock(@thread_times); push(@thread_times, $runtime); }
 print "Thread ".threads::tid()." :: stopped at ".localtime()."\n";
 return $runtime;
}

# Setup
my $num_threads = shift || 2;
print "Running with $num_threads threads\n";

# Main code
my $master_start = time();
my @threads = map { threads->create(\&workfunc, rand(10)); } 1 .. $num_threads;
my $thread_time = 0;
for my $t (@threads) {
 $thread_time += $t->join();
}
my $master_time = time() - $master_start;

# Find and print times
my $lock_time = 0;
{ lock(@thread_times); $lock_time += $_ for @thread_times; }
print "Master logged $master_time runtime\n";
print "Threads reported $lock_time combined runtime\n";