CPU usage with iostat
Hi,
Why the first execution of "iostat -c" always displays the same values?
[root@abc ~]# iostat -c
Linux 2.6.9-55.ELsmp (abc) 11/26/2010
avg-cpu: %user %nice %sys %iowait %idle
5.62 0.00 3.08 3.30 88.00
[root@abc ~]# iostat -c
Linux 2.6.9-55.ELsmp (abc) 11/26/2010
avg-cpu: %user %nice %sys %iowait %idle
5.62 0.00 3.08 3.30 88.00
[root@abc ~]# iostat -c
Linux 2.6.9-55.ELsmp (abc) 11/26/2010
avg-cpu: %user %nice %sys %iowait %idle
5.62 0.00 3.08 3.30 88.00
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When I use "iostat -c 1" the next values are modified:
[root@abc ~]# iostat -c 1
Linux 2.6.9-55.ELsmp (abc) 11/26/2010
avg-cpu: %user %nice %sys %iowait %idle
5.62 0.00 3.08 3.30 88.00
avg-cpu: %user %nice %sys %iowait %idle
2.00 0.00 4.00 23.25 70.75
avg-cpu: %user %nice %sys %iowait %idle
0.75 0.00 1.74 24.38 73.13
avg-cpu: %user %nice %sys %iowait %idle
0.25 0.00 0.50 24.56 74.69
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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?*
--
Att.
Bruno Galindro da Costa
bruno.galindro(a)gmail.com
http://www.thevenusproject.com/
http://www.arthurvinicius.com.br/
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