Runtime environment variables

The following environment variables are used by the system loader or by your application when it is executed. All of these variables are optional.

LD_LIBRARY_PATH

Specifies an alternate directory search path for dynamically linked libraries at application run time. If shared libraries required by your application have been moved to an alternate directory that was not specified at link time, and you do not want to relink the executable, you can set this environment variable to allow the dynamic linker to locate them at run time. For more information about this environment variable, see your operating system documentation.

PDFDIR

Optionally specifies the directory in which profiling information is saved when you run an application that you have compiled with the -qpdf1 option. The default value is unset, and the compiler places the profile data file in the current working directory. If the PDFDIR environment variable is set but the specified directory does not exist, the compiler issues a warning message. When you recompile or relink your program with the -qpdf2 option, the compiler uses the data saved in this directory to optimize the application. It is recommended that you set this variable to an absolute path if you use profile-directed feedback (PDF). See -qpdf1, -qpdf2 for more information.

PDF_PM_EVENT

When you run an application compiled with -qpdf1=level=2 and want to gather different levels of cache-miss profiling information, set the PDF_PM_EVENT environment variable to L1MISS, L2MISS, or L3MISS (if applicable) accordingly.

PDF_BIND_PROCESSOR

If you want to bind your process to a particular processor, you can specify the PDF_BIND_PROCESSOR environment variable to bind the process tree from the executable to a different processor. Processor 0 is set by default.

PDF_WL_ID

This environment variable is used to distinguish the sets of PDF counters that are generated by multiple training runs of the user program. Each run receives distinct input.

By default, PDF counters for training runs after the first training run are added to the first and the only set of PDF counters. This behavior can be changed by setting the PDF_WL_ID environment variable before each PDF training run. You can set PDF_WL_ID to an integer value in the range 1 - 65535. The PDF runtime library then uses this number to tag the set of PDF counters that are generated by this training run. After all the training runs complete, the PDF profile file contains multiple sets of PDF counters, each set with an ID number.