Starting threads in Perl is rather expensive. It's far faster to reuse threads (e.g. using a worker model). You've indicated otherwise, but that simply points to a problem with the implementation you used.
use strict;
use warnings;
use feature qw( say );
use threads;
use Thread::Queue qw( );
use Thread::Semaphore qw( );
use Time::HiRes qw( time );
use constant MAX_WORKERS => 32;
use constant NUM_JOBS => 1_000;
{
my $sem = Thread::Semaphore->new(MAX_WORKERS);
my $s = time;
for my $job (1..NUM_JOBS) {
$sem->down();
$_->join() for threads->list(threads::joinable);
async {
# ...
$sem->up();
};
}
$_->join() for threads->list();
my $e = time;
say($e-$s); # 5.88567113876343
}
{
my $q = Thread::Queue->new();
for (1..MAX_WORKERS) {
async {
while (defined( my $job = $q->dequeue() )) {
# ...
}
};
}
my $s = time;
$q->enqueue($_) for 1..NUM_JOBS;
$q->end();
$_->join() for threads->list();
my $e = time;
say($e-$s); # 0.248196125030518
}
Things couldn't be any more ideal for creating threads (minimal amount of variables to clone), yet creating all those threads was 25x slower than reusing a few threads. (The factor will grow as the number of jobs increases.)
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