Bug#660662: Acknowledgement (sysstat: mpstat shows 0% idle incorrectly)

[Michael Mastrogiacomo]

I implemented my own (1 second interval) mpstat command in Perl which seems
to not have the aforementioned bug, getting CPU metrics directly from
/proc/stat.  I thought I'd send it over to you in case it helps troubleshoot
the issue.  

Thanks



-----Original Message-----
From: Debian BTS [mailto:debb...@busoni.debian.org] On Behalf Of Debian Bug
Tracking System
Sent: Monday, February 20, 2012 1:03 PM
To: mmastrogiac...@ultralogistics.com
Subject: Bug#660662: Acknowledgement (sysstat: mpstat shows 0% idle
incorrectly)

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660662: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=660662
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#!/usr/bin/perl
#NAME: Michael Mastrogiacomo
#DATE: 02-20-2012

print "cpu\t%idle\n";

open(STAT, "< /proc/stat") or die;
while(<STAT>)
{
   if (/^cpu(\d+)/)
   {
      $cpu = $1;
      @f = split;
      $idle_before{$cpu} = $f[4];
      $total_before{$cpu} = $f[1] + $f[2] + $f[3] + $f[4] + $f[5] + $f[6] + 
$f[7] + $f[8] +  $f[9];
   }
}
close(STAT) or die;

sleep(1);

open(STAT, "< /proc/stat") or die;
while(<STAT>)
{
   if (/^cpu(\d+)/)
   {
      $cpu = $1;
      @f = split;
      $idle_after{$cpu} = $f[4];
      $total_after{$cpu} = $f[1] + $f[2] + $f[3] + $f[4] + $f[5] + $f[6] + 
$f[7] + $f[8] +  $f[9];
   }
}
close(STAT) or die;

for($i=0; $i <= $cpu; $i++)
{
   $total = $total_after{$i} - $total_before{$i};
   $idle = $idle_after{$i} - $idle_before{$i};

   if ($total == 0) #avoid division by 0 errors
   {
       $percent_busy = 0;
   }
    else
   {
       $percent_busy = ($total - $idle) * 100 / $total;
   }

   # round it down and add 1 for the percent_busy value for printing
   $show_idle = 100 - int($percent_busy);
   print $i . "\t" . $show_idle . "\n";
}