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Motivation

A couple basic tools are included with most linux distributions providing code coverage analysis and function profiling: gcov and gprof.  Using just these 2 tools, it's easy to gain understanding of how your code is running.  With the linuxtools Eclipse incubation project ( http://www.eclipse.org/linuxtools/  , now bundled with PTP ) , gprof and gcov are fully integrated into the cdt editor perspective.  Let's see how the linuxtools project adds value and puts a fresh look on these classic linux code analysis tools.

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To use gprof and gcov, add the appropriate flags to the Makefile.  I'll run a single test job to get both profile and coverage data at once by using -pg for gprof and "-ftest-coverage -fprofile-arcs" for gcov (-g is included so that we have source code line numbering available).  Do a project .> refresh and note the additional files created for use by gcov after compiling with "-ftest-coverage -fprofile-arcs". Image Removed Image Added

Setup the MPI run configuration with the Environment variable GMON_OUT_PREFIX defined with a name for your individual MPI rank gmon outputs.  By default gmon.out is used but MPI doesn't do that well and you end up with a profile that's missing most of the information, so by using GMON_OUT_PREFIX, each MPI rank adds its process id to its gmon output filename. 

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galen@lgheron:~/workspace/shallow$ gprof -s shallow gmon_*
galen@lgheron:~/workspace/shallow$ ls
calc.c     decs.h     eclipse.inc        init.o        time.c      worker.c
calc.gcda  diag.c     gmon_shallow.9885  main.c        time.gcda   worker.gcda
calc.gcno  diag.gcda  gmon_shallow.9886  main.gcda     time.gcno   worker.gcno
calc.o     diag.gcno  gmon_shallow.9887  main.gcno     time.o      worker.o
copy.c     diag.o     gmon_shallow.9888  main.o        tstep.c
copy.gcda  dump.c     gmon.sum           Makefile      tstep.f90
copy.gcno  dump.gcda  init.c             Makefile.gem  tstep.gcda
copy.o     dump.gcno  init.gcda          Makefile.mk   tstep.gcno
CVS        dump.o     init.gcno          shallow       tstep.o
galen@lgheron:~/workspace/shallow$

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The gcov view is simlar to the gprof view but keep in mind that you're looking at code coverage and not necessarily performance or timing information (though there is a relationship...code not executed is performing quite well ! ).  Also note that multiple executions will accumulate values in the gcov output files until they are removed or truncated to zero-length (2nd run to demonstrate this).

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Selecting (double click) a source code line from either the gcov or gprof view and you'll see the file and routine highlighted in the cdt c/c++ perspective.  Also notice the support for the .f90 file and its routines.  Image Removed Image Removed Image Added Image Added

References:

http://wiki.eclipse.org/Linux_Tools_Project/GProf/User_Guide

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