#!/usr/bin/perl
use strict;
use warnings;
use threads;
use Time::HiRes qw(setitimer time ITIMER_REAL);

my $NUM = 5;

# install main signal handler before creating threads
$SIG{ALRM} = sub { local $|=1; print time, ": Caught SIGALRM in main\n" };
setitimer(ITIMER_REAL, 0.1, 0.1);

# create all the threads
my $tstart = time;
threads->create("run_thread", $_) for (1 .. $NUM);
my $tdone = time;

printf "%d threads in %f seconds == %d threads/second\n\n",
       $NUM,
       $tdone - $tstart,
       $NUM / ($tdone - $tstart);

sleep 1 while 1;


sub run_thread {
    my $num = shift;

    $SIG{ALRM} = sub {
        local $| = 1;
        print time, ": Caught SIGALRM in thread $num\n";
        print "\n" if $num == $NUM;
    };
    setitimer(ITIMER_REAL, 0.1, 0.1);

    sleep 1 while 1;
}

##</code><code>##

5 threads in 0.079028 seconds == 63 threads/second

1062803574.97634: Caught SIGALRM in main
1062803574.99621: Caught SIGALRM in thread 1
1062803575.02622: Caught SIGALRM in thread 2
1062803575.02631: Caught SIGALRM in thread 3
1062803575.04619: Caught SIGALRM in thread 4
1062803575.05619: Caught SIGALRM in thread 5

1062803575.07617: Caught SIGALRM in main
1062803575.09617: Caught SIGALRM in thread 1
1062803575.12616: Caught SIGALRM in thread 2
1062803575.12621: Caught SIGALRM in thread 3
1062803575.14616: Caught SIGALRM in thread 4
1062803575.15617: Caught SIGALRM in thread 5