PGO Environment Variables

The environment variables determine the directory in which to store dynamic information files or whether to overwrite pgopti.dpi. The PGO environment variables are described in the table below.




Specifies the directory in which dynamic information files are created. This variable applies to all three phases of the profiling process.


Initiates interval profile dumping in an instrumented user application.


Alters the feedback compilation phase slightly. By default, during the feedback compilation phase, the compiler merges the data from all dynamic information files and creates a new pgopti.dpi file, even if one already exists. When this variable is set, the compiler does not overwrite the existing pgopti.dpi file. Instead, the compiler issues a warning and you must remove the pgopti.dpi file if you want to use additional dynamic information files.

See the documentation for your operating system for instructions on how to specify environment variables and their values.