What kind of test are you doing via telnet? If you just want to check connectivity, a select loop on multiple sockets would suffice, no threads needed: 

$\=$/;
use IO::Socket::INET;


my @hosts = qw(pantagruel gargantua foo bar quux);

my (%active,%sockets);

my $maxconn = 30; # or as much as your OS permits ;-)
my $timeout = 20;

sub setup_sock {
    my $fh = eval {
        IO::Socket::INET->new(
           PeerAddr => "$_[0]:23",
           Blocking => 0,
        )
    };
    unless ($fh) {
        print "$_[0] not reachable";
        return;
    }   
    $active{$_[0]} = $fh;
    $sockets{fileno($fh)} = $_[0];
    # print "$_[0] fileno ",fileno($fh);
}

sub close_sock {
    my $fileno = shift;
    my $host   = $sockets{$fileno};
    $active{$host}->close;
    delete $active{$host};
    delete $sockets{$fileno};
}

sub set_bits {
    my $rin;
    for (keys %active) {
        vec($rin, fileno($active{$_}),1) = 1;
    }   
    $rin;
}   

while (@hosts || keys %active) {
    # $c++; print "pass $c";
    setup_sock(shift @hosts) while ($maxconn > keys %active and @hosts
+);
    my $rin = set_bits;
    my $rout; 
    select($rout=$rin,undef,undef,$timeout);

    # if there has been a timeout, there has been no response,
    # and $rout has no bit set. mark those hosts as unreachable

    if ($rout eq "\0") {
        for(0..unpack"B*",$rin) {
            if (vec $rin,$_,1) {
                print "no answer from $sockets{$_} (fileno $_)";
                close_sock($_);
            }
        }
    }

    for(0..unpack"B*",$rout) {
        if (vec $rout,$_,1) {
            print "$sockets{$_} ($_) is alive";
            close_sock($_);
        }   
    }   
}

[download]

If there's more to it, i.e chatting with the AP, then you might want to fire off threads for the check part (i.e. the close_sock() sub above.)

update: mhm. Maybe the bottleneck is moved to IO::Socket::INET->new() that way...

update2: nope ;-) ... you get to wait the full timeout only once per $maxconn if the %active hash is filled up with unresponsive peers.

In reply to Re: Testing many devices - are threads the answer? by shmem
in thread Testing many devices - are threads the answer? by McDarren

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.