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Debugging Tools

StarPU provides several tools to help debugging applications. Execution traces can be generated and displayed graphically, see Generating Traces With FxT.

Some gdb helpers are also provided to show the whole StarPU state:

(gdb) source tools/gdbinit
(gdb) help starpu

Valgrind can be used on StarPU: valgrind.h just needs to be found at ./configure time, to tell valgrind about some known false positives and disable host memory pinning. Other known false positives can be suppressed by giving the suppression files in tools/valgrind/ *.suppr to valgrind's –suppressions option.

The environment variable STARPU_DISABLE_KERNELS can also be set to 1 to make StarPU do everything (schedule tasks, transfer memory, etc.) except actually calling the application-provided kernel functions, i.e. the computation will not happen. This permits to quickly check that the task scheme is working properly.

The Temanejo task debugger can also be used, see Using The Temanejo Task Debugger.

Using The Temanejo Task Debugger

StarPU can connect to Temanejo >= 1.0rc2 (see http://www.hlrs.de/temanejo), to permit nice visual task debugging. To do so, build Temanejo's libayudame.so, install Ayudame.h to e.g. /usr/local/include, apply the tools/patch-ayudame to it to fix C build, re-./configure, make sure that it found it, rebuild StarPU. Run the Temanejo GUI, give it the path to your application, any options you want to pass it, the path to libayudame.so.

Make sure to specify at least the same number of CPUs in the dialog box as your machine has, otherwise an error will happen during execution. Future versions of Temanejo should be able to tell StarPU the number of CPUs to use.

Tag numbers have to be below 4000000000000000000ULL to be usable for Temanejo (so as to distinguish them from tasks).