IMO it makes sense to preload modules if these modules take a long time to initialize and you have a good chance of sharing their data among the forked copies.

Examples I can think of are caching some (largish) resources in memory, or modules that autogenerate lots of code.

Database connections sound interesting, but usually, DBI database handles need to be reinitialized after a fork() call, so that won't work.

"... modules take a long time to initialize..."

Ja, ja or yes sure as you like. This is what common sense tells us.

But consider this funny little study i recently posted:

# app.psgi
use strict;
use warnings;
use Plack::Request;
use Plack::App::URLMap;
use JSON::Tiny qw(encode_json);

my $slash = sub {
    my $env = shift;
    my $json = encode_json {nose => 'cuke'};
    my $status  = 200;
    my $request = Plack::Request->new($env);
    my $headers = [
        'Content-Type'   => 'application/json',
        'Content-Length' => length $json,
    ];
    my $body = [ $json ];
    [ $status, $headers, $body ];
};

my $urlmap = Plack::App::URLMap->new;

$urlmap->mount( "/" => $slash );

my $app = $urlmap->to_app;

__END__
[download]

Preloading the Plack stuff? JSON::Tiny might be cheap but who knows.

It is really difficult to find answers for these questions.

And what if i daemonize Starman? The switches for this task are confusing.

Thanks for your kind reply and best regards, Karl.

P.S.: I asked the author. Probably he will enlight us.

«The Crux of the Biscuit is the Apostrophe»

> > "... modules take a long time to initialize..."

> It is really difficult to find answers for these questions.

Is it? To benchmark initialization, measure time in BEGIN, CHECK and INIT blocks.

From what I heard is Moose a good candidate.

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery}

Update - I thought I should add what I knew to be true (at some point) and isn't a secret, cPanel pays people a a lot of money to maintain a build infrastructure that uses B::C to generate a binary from Perl simply to improve start up time of their administrative daemon, cpservd. Basically, many MBs of initializations and module loads are shoved into a BEGIN{}. The binary is the state of the perl start up through BEGIN (like what you get by invoking perl -c). My point is that this is also an option - if you have a lot of stuff to preload, B::C can be used to get you into a state where start up actually picks up after BEGIN.

Holy Joe! I just wanted to be on the Bright Side of Life.

Something like starman -Mstrict -Mwarnings -MPlack::Request -MPlack::App::URLMap -MPlack::App::URLMap. If the syntax is so. Untested. "Fire up and forget about it" was the basic theme. But i guess that i'm forced to do some forensics. Sometimes some things go totally wrong with a good cause. I wrote a very friendly email to the author. Result: undef. Regards, Karl

«The Crux of the Biscuit is the Apostrophe»