CPU usage with iostat

James McKenzie jjmckenzie51 at earthlink.net
Fri Nov 26 13:56:52 UTC 2010

On 11/26/10 5:47 AM, Bruno Galindro da Costa wrote:
> Hi,
>    Why the first execution of "iostat -c" always displays the same values?
> Reading the man pages os iostat, I could not understand these lines:
> /"The  first  report  generated  by the iostat command provides 
> statistics concerning the time since the system was booted. Each 
> subsequent report covers the time since the previous report."
> "The first report contains statistics for the time since system 
> startup (boot). Each subsequent report contains statistics collected 
> during the interval since the previous report."/
> *Why it can´t build a report with the current usage values at the 
> first execution?*
Because that is the way it was designed.  Most statistics programs 
record what has happened either since the last time they were run or 
from system start.  Analysts wanted it that way.  Maybe you can ask the 
folks that designed the program to do startup 'snapshots' by entering a 
numeric value.  That should not be so hard, but this will alter the 
programs functioning from what it used to be.

James McKenzie

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