#! perl -slw
use strict;
use warnings;
use Win32::Process::Info;
use List::Util qw[ sum ];

my $pi = Win32::Process::Info->new;
my @pids = $pi->ListPids;
my @proc_info;

my @fields = qw[ Name WorkingSetSize UserModeTime KernelModeTime ];

my %byPid;

while( 1 ) {
    my @pids = $pi->ListPids;
    for my $pid ( @pids ) {
        my @info =  $pi->GetProcInfo( { no_user_info => 1 }, $pid );
        for my $info ( @info ) {
            $byPid{ $pid }{ last } = [ @{ $info }{ @fields } ];
        }
    }
    sleep 1;
    for my $pid ( @pids ) {
        my @info =  $pi->GetProcInfo( { no_user_info => 1 }, $pid );
        for my $info ( @info ) {
            $byPid{ $pid }{ current } = [ @{ $info }{ @fields } ];
        }
    }
    my $totalDelta = 0;
    for my $pid ( @pids ) {
        $totalDelta += $byPid{ $pid }{ delta }
            = sum( @{ $byPid{ $pid }{ current } }[ 2, 3 ] )
            - sum( @{ $byPid{ $pid }{ last } }[ 2, 3 ] );
    }
    system 'cls';
    print "\n pid   Name                   memory  %cpu";
    for my $pid ( @pids ) {
        printf "%5d %20s %10u %.1f%%\n",
            $pid, @{ $byPid{ $pid }{ last } }[ 0, 1 ],
            $byPid{ $pid }{ delta } * 100 / ($totalDelta||1);
    }
}