timex commans

[Shay_1]

Hi

The timex reports in seconds the elapsed time, user time, and system time spent in execution of the given command.

Could anyone explain the meaning of the "user time", and system time ?

Thanks

Shay

[A. Clay Stephenson · Accepted solution]

Yes, it's just what it sounds like. User time is the amount of time spent in user space (e.g. your actual application) as opposed to the amount of time spent executing system (kernel) code (e.g. system (2) calls like read, write, sbrk,open, close, etc.).

[Sridhar Bhaskarla]

Hi Shay,

User Time means the time it spent in executing user instructions while system time is the time the process spent in executing the system instructions. System mode can be viewed something like writing to a disk or buffer cache that have to be done exclusively by the kernel instructions. Examples of user mode instructions are arthmatic calculations.

-Sri

[Roger Baptiste]

hi,

Yes, usertime is the time CPU spent running in usermode
and systemtime is the time CPU spent in Kernel mode.
So, if you are running a purely system command , the system time will be more. If you are running a user command which does more processing of records (sorting etc ), then the user time will be more.


If you run sar , even there you can see the user and system modes being displayed.
If the system mode value is more in SAR, then we consider it a problem, since it could be due to excess memory swapping or something on which the CPU is wasting time on.

HTH
raj