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Using PGO
To use profile-guided optimization, you must compile at least twice.
Follow these steps:
- Instrumented compilation
Compile using the -Qprof_gen option (-prof_gen
on Linux*).
Example: prompt>ecl -Qprof_gen test.c
- Instrumented execution
Run the application through a representative
workload to generate a profile. This step generates a data file
with a .dyn suffix and summary file of the
performance optimization data with the file name pgopti.dpi.
Example: prompt>test.exe
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Feedback compilation
Set the compiler to use the profile information the next time
you recompile the application, using the -Qprof_use
option (-prof_use on Linux). This step uses
the summary file generated in the previous step. The
-Qprof_dir option specifies the directory containing the feedback
information from the first step, and is required if the .dyn
files are not in the current directory.
Example: prompt>ecl -Qprof_use test.c
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