- Infos im HLRS Wiki sind nicht rechtsverbindlich und ohne Gewähr -

Valgrind

From HLRS Platforms
Valgrind is an award-winning instrumentation framework for building dynamic analysis tools. There are Valgrind tools that can automatically detect many memory management and threading bugs, and profile your programs in detail. You can also use Valgrind to build new tools.
Valgrind-logo.png
Developer: Valgrind Developers
Platforms: NEC Nehalem Cluster
Category: Debugger
License: GNU General Public License, version 2
Website: Valgrind homepage


Usage

In order to use Valgrind, you need to first load it:

module load tools/valgrind/3.6.1


To check your application with Valgrind, please use following command format (take ls command as an example):

valgrind ls


Please note, the default checking tool is Memcheck. If you want to use other tools in Valgrind, you have to specify it via --tool=<name> option.


Valgrind can also be used to check parallel application. For example, in order to check an MPI application, please follow the steps:

  • First reserve compute nodes:
qsub -I -lnodes=16:nehalem:ppn=8,walltime=1:0:0


  • Load all necessary tools:
module load tools/valgrind/3.6.1 mpi/openmpi/1.5.4-gnu-4.6.1


  • Run your MPI application with Valgrind:
mpirun -np 4 valgrind ./your_app


Note: For Open MPI there exists a suppression file which can be used with the following command
mpirun -np 4 valgrind --suppressions=$(dirname $(which mpirun))/../share/openmpi/openmpi-valgrind.supp  ./app


If you want to run Callgrind and later visualize the output in Kcachegrind, you have to do following steps:

  • Run your application with Callgrind:
valgrind --tool=callgrind ls


The above command will generate an output file with name callgrind.out.xxxx, where xxxx is the pid of the checked application.

  • Load Kcachegrind
module load tools/kcachegrind/0.7.0


  • Open Kcachegrind with the generated Callgrind output file. Or open Kcachegrind and load the callgrind file in the GUI.
kcachegrind callgrind.out.4076


You will see the Kcachegrind window similar to this:

Example of using Kcachegrind with Callgrind.

See also

External links