AWR Top 5 Timed Events - CPU Time
Most of the time we see CPU time in the TOP 5 list of AWR reports. So couple of questions we get to our mind is 1) Why the Wait Information is empty 2) How do we interpret the Time mentioned in the report.
1) Wait Information is empty because “CPU time” is not wait event. It is the time spent on CPU to do the actual work.
2) Interpretation of CPU Time(s) 1033
We have 60*60=3600 CPU Seconds to use in a particular interval for single CPU in 1 hour snap
In the example we have 8 CPU (Num_CPUs under the Operating System Statistics of AWR) which relates to 60*60*8= 28800 CPU seconds to use in 1 hr interval. ( Single Database Machine is running on machine)
(1033/28800)*100 = 3.58% of Total CPU
So we are not CPU bound and things looks good from CPU point of View.
Other way to look at the CPU information is to drill down to the operating system statistics and look for Busy Time and Idle Time. If the Idle Time is high then there is not much contention for the CPU.
Most of the time we see CPU time in the TOP 5 list of AWR reports. So couple of questions we get to our mind is 1) Why the Wait Information is empty 2) How do we interpret the Time mentioned in the report.
1) Wait Information is empty because “CPU time” is not wait event. It is the time spent on CPU to do the actual work.
2) Interpretation of CPU Time(s) 1033
We have 60*60=3600 CPU Seconds to use in a particular interval for single CPU in 1 hour snap
In the example we have 8 CPU (Num_CPUs under the Operating System Statistics of AWR) which relates to 60*60*8= 28800 CPU seconds to use in 1 hr interval. ( Single Database Machine is running on machine)
(1033/28800)*100 = 3.58% of Total CPU
So we are not CPU bound and things looks good from CPU point of View.
Other way to look at the CPU information is to drill down to the operating system statistics and look for Busy Time and Idle Time. If the Idle Time is high then there is not much contention for the CPU.
3 comments:
Good explanation.
Thanks for writing in such simple language.
Nice one .Can you please explain "db file sequential read" and "TCP Socket (KGAS)" wait event also ?
Thx
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