CPU time is taken from OS macros which compute the time the statementneeds CPU cycles.i.e the CPU times are not timestamp related, they are taken from OS CPUmacros, meaning CPU times are recorded based on CPU usage per process.So even though the exec...
显示全部CPU time is taken from OS macros which compute the time the statement
needs CPU cycles.
i.e the CPU times are not timestamp related, they are taken from OS CPU
macros, meaning CPU times are recorded based on CPU usage per process.
So even though the execution time may take 30secs, the process only used
the CPU for 1 second.
There are plenty of time not included in the user+sys cpu time.
- fcm communication
- wait for prefetcher,
- wait for log writter
- wait for....... what ever.
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