7.3 Runtime Command Line Arguments

Various following command line arguments will affect the behavior of the program when running with the control point framework. As this is an experimental framework, these are subject to change.

The scheme used for tuning can be selected at runtime by the use of one of the following options:

     +CPSchemeRandom            Randomly Select Control Point Values
 +CPExhaustiveSearch            Exhaustive Search of Control Point Values
      +CPSimulAnneal            Simulated Annealing Search of Control Point Values
 +CPCriticalPathPrio            Use Critical Path to adapt Control Point Values
        +CPBestKnown            Use BestKnown Timing for Control Point Values
         +CPSteering            Use Steering to adjust Control Point Values
      +CPMemoryAware            Adjust control points to approach available memory

To intelligently tune or steer an application's performance, performance measurements ought to be used. Some of the schemes above require that memory footprint statistics and utilization statistics be gathered. All measurements are performed by a tracing module that has some overheads, so is not enabled by default. To use any type of measurement based steering scheme, it is necessary to add a runtime command line argument to the user program to enable the tracing module:

    +CPEnableMeasurements

The following flags enable the gathering of the different types of available measurements.

        +CPGatherAll            Gather all types of measurements for each phase
+CPGatherMemoryUsage            Gather memory usage after each phase
+CPGatherUtilization            Gather utilization & Idle time after each phase

The control point framework will periodically adapt the control point values. The following command line flag determines the frequency at which the control point framework will attempt to adjust things.

     +CPSamplePeriod     number The time between Control Point Framework samples (in seconds)

The data from one run of the program can be saved and used in subsequent runs. The following command line arguments specify that a file named controlPointData.txt should be created or loaded. This file contains measurements for each phase as well as the control point values used in each phase.

         +CPSaveData            Save Control Point timings & configurations at completion
         +CPLoadData            Load Control Point timings & configurations at startup
     +CPDataFilename            Specify the data filename

It might be useful for example, to run once with +CPSimulAnneal +CPSaveData to try to find a good configuration for the program, and then use +CPBestKnown +CPLoadData for all subsequent production runs.