Thanks. I took a closer look at LWP::Parallel and it may come in handy later¹. From the documentation, I see how to fetch batches of links and wonder if there is any way to parallelize the processing of the results in the same move. That way fetch+process runs continuously, rather than fetch in parallel wait and then process in parallel.

I'll be digging into the options mentioned in the other threads, too.

#!/usr/bin/perl

use LWP::Parallel::UserAgent;

use strict;
use warnings;

my @feeds = (
    'http://localhost/feed1.xml',    # rss
    'http://localhost/feed2.xml',    # atom
    'http://localhost/foo',        # 404
    );

my $requests = &prepare_requests(@feeds);
my $entries  = &fetch_feeds($requests);

foreach my $k (keys %$entries) {
    my $res = $entries->{$k}->response;
    print "Answer for '",$res->request->url,"' was \t",
        $res->code,": ", $res->message,"\n";
    #    $res->content,"\n";
}

exit(0);

sub prepare_requests {
    my (@feeds) = (@_);
    my $requests;
    foreach my $url (@feeds) {
        push(@$requests, HTTP::Request->new('GET', $url));
    }
    return($requests);
}

sub fetch_feeds {
    my ($requests) = (@_);

    my $pua = LWP::Parallel::UserAgent->new();
    $pua->in_order  (0);  # handle requests in order of registration
    $pua->duplicates(1);  # ignore duplicates
    $pua->timeout   (9);  # in seconds
    $pua->redirect  (1);  # follow redirects
    $pua->max_hosts (3);  # max locations accessed in parallel
    
    foreach my $req (@$requests) {
        print "Registering '".$req->url."'\n";
        if (my $res=$pua->register($req, \&handle_answer, 8192, 1)) { 
            # print STDERR $res->error_as_HTML; 
            print $res->error_as_HTML; 
        } else {
            print qq(ok\n);
        }
    }
    my $entries = $pua->wait();
    return($entries);
}

sub handle_answer {
    my($content, $response, $protocol, $entry) = @_;
    if (length($content)) {
        $response->add_content($content);
    } else {
        1;
    }
    return(undef);
}
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¹ That's the thing about CPAN, there are so many useful modules with great accompanying documentation that discovery can be a challenge. So I am very appreciative of everyone's input here.