I found few more places in AnyEvent::HTTP (mostly on_error handlers) where reason is taken from outside. To be sure, I added some prefix to those error messages and indeed the error comes from tcp_connect.

Knowing the limitation, I was able to work around. Not that I like hardcoding the number 10 like this, but limit connections is probably good idea anyway.

use AnyEvent::HTTP;

my @urls = map { chomp; $_ } <DATA>;

while(my @ten_urls = splice(@urls,0,10)) {
    my $cv = AnyEvent->condvar;
    for my $url (@ten_urls) {
        $cv->begin;
        http_get $url, timeout => 5, sub {
            my ($body, $hdr) = @_;
            warn "[$hdr->{Status}:$hdr->{Reason}] ",$url," (",length($
+body),")\n";
            $cv->end;
        };
    }
    $cv->recv;
    warn "-----","\n";
}
[download]

Really appreciate your help.

-- thanks, Roman