#!/usr/bin/perl
#Modify the first line and the line below ($PIO =...) as needed.
#topio 1.1: This Perl script launches pio (Process I/O) to probe all processes
#on the system and sort them based on absolute or delta Read/Write Characters
#for each process.

$PIO = "/usr/local/bin/pio";

########## No need to modify below this line but hacking is welcome. ##########

use Getopt::Std;

getopts('ds:n:h');

if (defined $opt_h)
 { print "Usage: $0 [-d] [-s Delay] [-n Top_n_lines] [-h]
    -d: Show delta Read/Write Characters between calls of pio
    -s: Number of seconds delay between calls (default 5)
    -n: Only show processes of top n RWChar or (if -d) deltaRWChar (default 10)
    -h: Show this Usage\n";
   exit;
 }

$opt_s = 5 if !defined $opt_s;
$opt_n = 10 if !defined $opt_n;

if (defined $opt_d)
{
#Format to be used by write
format =
@>>>> @>>>>>>>>>>>>>>> @>>>>>> @<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
$_,   $pio{$_},        $iodiff{$_}, $comm
.

undef $/;
while (1)
 { $_ = qx{$PIO -A};	#slurp in all pio -A output

   @lines = split /\n/;
   @allpids = ();	#@allpids is used to delete pid's that're gone between
			#calls to pio
   foreach (@lines)
    { next if /^$/;
      @line = split /\t/;
	#$line[0]: pid; $pio{$line[0]}: Saved RWChar for this pid
      if (defined $pio{$line[0]})	
	#$line[3]: RWChar; $iodiff{$line[0]}: delta RWChar for this pid
       { $iodiff{$line[0]} = $line[3] - $pio{$line[0]};
       }
      $pio{$line[0]} = $line[3];
      $allpids{$line[0]} = 1;	#create this hash for all current processes
    }

   foreach $pid (keys %pio)
    { delete $pio{$pid} if ! exists $allpids{$pid};	#this process disappears
    }

   if (defined $show)	#prevent printing all 0's the first time around
    { $n = 0;
      print "--PID-----------RWChar--DifRWC Command------------------------------------------\n";

      foreach (sort { $iodiff{$b} <=> $iodiff{$a} } keys %iodiff)
       { #A poor man's way to provide command for pid (added 20040730)
         $comm = qx{/usr/bin/ps -ocomm= -p $_};
         write if defined $iodiff{$_}; #print using the format defined earlier
         last if ++$n == $opt_n;
       }
    }
   $show = 1;

   sleep $opt_s;
 }

}
else	#Don't reinvent the wheel. Use shell sort.
{ warn "** WARNING: Running topio without -d may not be **
** what you want. Type topio -h for help.       **\n";
system("
while true; do
 echo 'PID\tInpBlk\tOutpBlk\tRWChar'
 $PIO -A | sort -nr -k 4,4 | head -$opt_n
 sleep $opt_s
done
");
}