Score-P¶

Introduction¶

The Score-P measurement infrastructure is a highly scalable and easy-to-use tool suite for profiling, event tracing, and online analysis of HPC applications.

Score-P can be used as an instrumentation tool for Scalasca.

Installed Versions¶

For the current list of installed versions, use:

$ ml av Score-P

Instrumentation¶

There are three ways to instrument your parallel applications in order to enable performance data collection:

Automated instrumentation using compiler
Manual instrumentation using API calls
Manual instrumentation using directives

Automated Instrumentation¶

This the easiest method. Score-P will automatically add instrumentation to every routine entry and exit using compiler hooks, and will intercept MPI calls and OpenMP regions. However, this method might produce a large number of data. If you want to focus on profiling a specific regions of your code, consider using the manual instrumentation methods. To use automated instrumentation, simply prepend scorep to your compilation command. For example, replace:

$ mpif90 -c foo.f90
$ mpif90 -c bar.f90
$ mpif90 -o myapp foo.o bar.o

with:

$ scorep mpif90 -c foo.f90
$ scorep mpif90 -c bar.f90
$ scorep mpif90 -o myapp foo.o bar.o

Usually your program is compiled using a Makefile or similar script, so it is advisable to add the scorep command to your definition of variables CC, CXX, FCC, etc.

It is important that scorep is prepended also to the linking command, in order to link with Score-P instrumentation libraries.

Manual Instrumentation Using API Calls¶

To use this kind of instrumentation, use scorep with the --user switch. You will then mark regions to be instrumented by inserting API calls.

An example in C/C++:

#include <scorep/SCOREP_User.h>
void foo()
{
    SCOREP_USER_REGION_DEFINE( my_region_handle )
    // more declarations
    SCOREP_USER_REGION_BEGIN( my_region_handle, "foo", SCOREP_USER_REGION_TYPE_COMMON )
    // do something
    SCOREP_USER_REGION_END( my_region_handle )
}

and Fortran:

#include "scorep/SCOREP_User.inc"
subroutine foo
    SCOREP_USER_REGION_DEFINE( my_region_handle )
    ! more declarations
    SCOREP_USER_REGION_BEGIN( my_region_handle, "foo", SCOREP_USER_REGION_TYPE_COMMON )
    ! do something
    SCOREP_USER_REGION_END( my_region_handle )
end subroutine foo

Refer to the documentation for description of the API.

Manual Instrumentation Using Directives¶

This method uses POMP2 directives to mark regions to be instrumented. To use this method, use the scorep --pomp command.

Example directives in C/C++:

void foo(...)
{
    /* declarations */
    #pragma pomp inst begin(foo)
    ...
    if (<condition>)
    {
        #pragma pomp inst altend(foo)
        return;
    }
    ...
    #pragma pomp inst end(foo)
}

and in Fortran:

subroutine foo(...)
    !declarations
    !POMP$ INST BEGIN(foo)
    ...
    if (<condition>) then
 !POMP$ INST ALTEND(foo)
 return
 end if
 ...
 !POMP$ INST END(foo)
end subroutine foo

The directives are ignored if the program is compiled without Score-P. For details, refer to the documentation.