Hello

I ran into a strange (to my eyes) behaviour of perl 5.8s threads. Maybe I'm just doing things wrong or have the wrong impression on how things are meant to work.

I'm using 5.8 threads and Net::FTP, to execute one command on a couple FTP Servers at the same time. After connecting to all FTP Servers and storing the connect hash, i create a thread for every FTP to execute a command. It seems to me that when creating the threads to execute the command, the threads are blocking. Eg the commands don't happen in parallel but in serial.

I would be glad if someone could enlighten me if I misunderstood something about the threading implementation of perl, or if i'm doing something seriously wrong about the threads. The whole thing is running on RH7.2 with perl compiled from cpan.

Here some snippets of my code (the whole thing is too big to paste here):

## @ftp is an array holding the name of the respective ftp servers 

for ($i=0;$i<scalar(@ftp);$i++)
{
    $ftpconnect[$i] = ftp_connect($host[$i],$port[$i],$user[$i],$pass[
+$i],$dir[$i]);
}

for ($i=0;$i<scalar(@ftp);$i++)
{
    $thread[$i] = threads->create("ftp_exec",$ftpconnect[$i],$command[
+$i]);
    ## this is where it seems it's blocking? or just taking an awful l
+ong time to create each thread.
    ## although it's necessary that the commands get executed at the e
+xact same time everywhere.
}

######## maximum time a command takes is around 30 seconds ########
sleep(30);

for ($i=0;$i<scalar(@ftp);$i++)
{
    $thread[$i]->join();
}

### subs

sub ftp_connect
{                       
        my ($remoteHost, $remotePort, $remoteUser, $remotePwd, $remote
+dir) = @_;
        my $ftp = Net::FTP->new($remoteHost,Port=>$remotePort,Debug=>1
+);
        if ($ftp)
        {       
                $ftp->login($remoteUser,$remotePwd);
                if (!$ftp->cwd($remotedir)) { $ftp->quit; return ("dir
+ectory doesn't exist?"); }
                $ftp->type('I');
        }
        return ($ftp);  
}        

sub ftp_exec
{
    my ($ftp,$cmd) = @_;
    $ftp->quot("$cmd");
    $ftp->quit();
}

[download]

thanks in advance
.emanuel

In reply to 5.8 threads blocking/slow by Emanuel

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