Developer Tools

Debuggers

On Midway3 GDB and Valgrind as modules for debugging and memory leak checking with your code.

To debug your code with gdb, you compile your code with -g and then run gdb:

  g++ -g -o test test.cpp
  module load gdb
  gdb --args ./test param1 param2

You can also use gdb to debug your Python codes. Alternatively, use pbd.

  python3 -m pdb myscript.py

To check if there is any memory leak with your code, use valgrind

  g++ -g -o test test.cpp
  module load valgrind
  valgrind --leak-check=full --track-origins=yes ./test param1 param2

Please refer to the official documentation of GDB and Valgrind for more information.

For CUDA codes, after loading the CUDA toolkit module you can use cuda-gdb and cuda-memcheck.

Profilers

TAU is a tool for profiling and tracing toolkit for performance analysis of parallel programs written in Fortran, C, C++, UPC, Java, Python. You can load tau/2.31 on Midway3.

The TAU binaries and scripts in the subfolders $TAU_HOME/bin, and several Makefile.* in $TAU_HOME/lib . To use TAU, you need to rebuild your code using one of the scripts inside $TAU_HOME/bin: C codes use tau_cc.sh; C++ codes use tau_cxx.sh (see for example, the doc page at OLCF). Should a new Makefile.foo be needed, then the CC and CXX environment variables need to be exported:

export CC=tau_cc.sh CXX=tau_cxx.sh F90=tau_f90.sh

before the first cmake run, or before running make.

Run the generated binaries as usual (e.g. mpirun -np 4 ./binary args) the output will now include the files profile.* in the working directory. At this point, run paraprof to launch the GUI analysis (need module load java), or pprof for command-line output.

Different options for compile time are available (e.g. -optVerbose), options for run time (e.g. TAU_TRACK_MEMORY_LEAKS=1)