Print message for ExecutionTime

mahmoodn · March 19, 2018, 08:04

Using the CUDA solver, I see the following info at each time step

Code:

Time = 10

cudaCG:  Solving for T, Initial residual = 9.9545596e-07, Final residual = 9.9545596e-07, No Iterations 0
ExecutionTime = 5.68 s  ClockTime = 5 s

I greped to see which part of the code prints that time. However, there are so many instances and I can not figure out which one is correct. Does anybody know?

RobertHB · March 19, 2018, 08:59

The ExecutionTime is the time needed by the CPU for the iteration step and ClockTime is the "real" Time.
Further information can be found here: Difference between "ExecutionTime" and "ClockTime"

mahmoodn · March 19, 2018, 14:55

OK. But I would like to know which source file is used for printing that information. As I said, there are multiple instances in the source folder.

Also, from you explanation I think ClockTime should be bigger than ExecutionTime. But I see the inverse. Can you explain more?

RobertHB · March 20, 2018, 04:00

From my observation the ClockTime is allways a whole number, while ExecutionTime gives the exact fractions. Also ExecutionTime can be smaller or larger (by a few fractions) than the ClockTime.

The printout is from solver.C:

Code:

        Info<< "ExecutionTime = " << runTime.elapsedCpuTime() << " s"
            << "  ClockTime = " << runTime.elapsedClockTime() << " s"
            << nl << endl;

March 19, 2018, 08:04	Print message for ExecutionTime	#1
mahmoodn Member Join Date: Mar 2016 Posts: 33 Rep Power: 11	Using the CUDA solver, I see the following info at each time step Code: Time = 10 cudaCG: Solving for T, Initial residual = 9.9545596e-07, Final residual = 9.9545596e-07, No Iterations 0 ExecutionTime = 5.68 s ClockTime = 5 s I greped to see which part of the code prints that time. However, there are so many instances and I can not figure out which one is correct. Does anybody know?

March 20, 2018, 04:00		#4
RobertHB Senior Member Robert Join Date: May 2015 Location: Bremen, GER Posts: 292 Rep Power: 13	From my observation the ClockTime is allways a whole number, while ExecutionTime gives the exact fractions. Also ExecutionTime can be smaller or larger (by a few fractions) than the ClockTime. The printout is from solver.C: Code: Info<< "ExecutionTime = " << runTime.elapsedCpuTime() << " s" << " ClockTime = " << runTime.elapsedClockTime() << " s" << nl << endl;

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March 19, 2018, 08:59		#2
RobertHB Senior Member Robert Join Date: May 2015 Location: Bremen, GER Posts: 292 Rep Power: 13	The ExecutionTime is the time needed by the CPU for the iteration step and ClockTime is the "real" Time. Further information can be found here: Difference between "ExecutionTime" and "ClockTime"

March 19, 2018, 14:55		#3
mahmoodn Member Join Date: Mar 2016 Posts: 33 Rep Power: 11	OK. But I would like to know which source file is used for printing that information. As I said, there are multiple instances in the source folder. Also, from you explanation I think ClockTime should be bigger than ExecutionTime. But I see the inverse. Can you explain more?