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Update of BG/Q Software

Recompiling Applications and Tools

It is recommended that applications be recompiled after installing a new release of Blue Gene/Q software. By recompiling your application for the new release, you ensure that your application will take advantage of the new features contained within the release. Some examples would be improvements in the Message Passing Interface (MPI) libraries. There are functional and performance enhancements to MPI in each release, and recompiling your applications will link to the latest libraries. Also, there are compiler optimizations that can result in more efficient code, and you should recompile to take advantage of these improvements.

Any programming tools that depend upon components within the new release should be recompiled. For example, because the PAPI (Performance API) tool depends upon the BGPM library
within the new release (interface to the hardware performance counters), the PAPI tool should be recompiled and reinstalled so that applications that are instrumented with PAPI will be compatible as they are recompiled for the new release.

Some basic applications or test cases may continue to run normally when installing a new release, even if they are not recompiled. If they are not performance critical or perhaps are not heavily reliant on MPI, it may not be necessary to recompile. Furthermore, the more basic applications may not be impacted by any changes in the Blue Gene/Q software or kernels. However, as a general guideline, it is recommended that all nontrivial applications be recompiled for the new release.