#!/usr/bin/perl

# disk stat thru sys/block/<dev>stats

$fbase = "/sys/block/";

$devpattern = qr#^$base(dm-\d+|sd.+)$#i;

$sleep = 1;

%nodiff = ( 8 => 1 );

@header = qw ( dev r-io r-merge r-sect r-tick w-io w-merge w-sect w-tick inflight iotick timeinQ );

@devs = grep { s/^\s+|\s+$//g,1 } grep { /$devpattern/ } qx( ls $fbase );

while( 1 ) {

  print chr(27), "[2J", chr(27), '[f';

  foreach $h (@header) {

    printf "%-12s ", $h;

  }

  print "\n";

  for $i ( 0 .. $#devs ) {

    $s = qx( cat $fbase$devs[$i]/stat ); chomp $s; $s =~ s/^\s+|\s+$//g;

    @a = split /\s+/, $s;

    print $devs[$i], "\t";

    for $j ( 0 ..  $#a ) {

      if( $nodiff{$j} ) {

        printf "%12i;", $a[$j];

      } else {

        printf "%12i ", $a[$j] - $prev[$i][$j];

        $prev[$i][$j] = $a[$j];

      }

    }

    print "\n";

  }

  sleep $sleep;

}