#! perl -slw
use strict;
use threads;
use threads::shared;
use Thread::Queue;
use Math::BigInt;
use List::Util qw[ shuffle ];
use Time::HiRes qw[ time ];
use Data::Dump qw[ pp ];
use feature qw(say);

our $T //= 4;

my %result : shared;

sub process {
    my $Q = shift;
    my $n = 0;
    while( my $number = $Q->dequeue ) {
        my $factorial = factorial($number);
        lock %result;
        $result{$number} = $factorial->bstr;
        ++$n;
    }
    printf "[%2u] terminating at %f; having processed %u values\n", threads->tid, time(), $n;
}

sub factorial {
    my $number = shift;
    Math::BigInt->bfac($number);
}

my $start = time;

my $Q = new Thread::Queue;
$Q->enqueue( (shuffle 1..2000 )[ 0 .. 999 ], (undef) x $T );

my @threads = map { threads->create( \&process, $Q ); } 1 .. $T;

$_->join for @threads;
my $end = time;
printf "Took %.6f seconds\n", $end - $start;

##</code><code>##

C:\test>1126584-q
[ 4] terminating at 1431869328.993618; having processed 280 values
[ 1] terminating at 1431869329.076621; having processed 305 values
[ 3] terminating at 1431869329.094198; having processed 190 values
[ 2] terminating at 1431869329.102986; having processed 225 values
Took 17.553564 seconds