I have two PERL SCRIPT that stress CPU and MEMORY. I want to run them in parallel on hosts so I am trying to copy them on all the hosts and run them in parallel. I am utilizing a module Net::OpenSSH::Parallel to copy (which is working) and run the commands on all the nodes. I am not able to run these two SCRIPTS in parallel. I have tried to take the SCRIPT to background but only one of them runs. Could you guide where am I going wrong?

CPU SCRIPT
#!/usr/bin/perl

use strict;
use warnings;

my @cpu_cores = qw(4);
while (--$cpu_cores[0] and fork) {};
while () {};

MEMORY SCRIPT
#!/usr/bin/perl

use strict;
use warnings;

print "$$";
fork for 1 .. 4;
for (1 .. 10000) {
my $a = "xxxxx" x int rand 10_000_000;
my $b = ~$a;
my $c = reverse $b;

MAIN SCRIPT
use strict;
use warnings;
use Net::OpenSSH::Parallel;
use Term::ANSIColor;
use DBI;

#--------------------------------------------------------
#FINDING HOSTS FROM CLOUDERA MANAGER DATABASE
#--------------------------------------------------------

print color 'bold blue';
print " Finding hostname of the hosts configured\n\n";

my $ip_address = `ping r01mgt -w 1 | awk -F "(" '/PING/{print \$2}' | 
+awk -F")" '{print \$1}'`;
chomp($ip_address);


# connect
my $dbh = DBI->connect("DBI:Pg:dbname=xxxx;host=$ip_address", "xxxx", 
+"xxxx", {'RaiseError' => 1});

# execute SELECT query
my $sth = $dbh->prepare("SELECT name FROM hosts");
$sth->execute();


# iterate through resultset and create an array
my @hosts;
while(my $ref = $sth->fetchrow_hashref())
{
my($nodename, $hadoopname) = $ref->{'name'} =~ m/(\w+).(\w+)/;
push(@hosts, "$nodename");
}
@hosts = sort (@hosts);
print color 'reset';

#-----------------------------------------------------------
#COPYING THE PERL SCRIPTS AND EXECUTING THEM
#-----------------------------------------------------------

my $pssh = Net::OpenSSH::Parallel->new();
$pssh->add_host($_) for @hosts;
$pssh->push('*', scp_put => '/root/cpu.pl', '/root/');
$pssh->push('*', scp_put => '/root/memory.pl', '/root/');
$pssh->push('*', command => '/usr/bin/perl', '/root/cpu.pl', '/tmp/cpu
+');
$pssh->push('*', command => '/usr/bin/perl', '/root/memory.pl', '/tmp/
+memory');
$pssh->run;

USING THREADS TO RUN SCRIPTS IN PARALLEL
#!/usr/bin/perl

use strict;
use warnings;
use threads;

sub cpu {
my @cpu_cores = qw(4);
print "CPU";
while (--$cpu_cores[0] and fork) {};
while () {};
}

sub memory {
print "MEMORY";
fork for 1 .. 4;
for (1 .. 10000) {
my $a = "xxxxx" x int rand 10_000_000;
my $b = ~$a;
my $c = reverse $b;
}
}
my $firstThread = threads->create(\&cpu);
my $secondThread = threads->create(\&memory);

$_->join() foreach ( $firstThread, $secondThread );
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