TAU

TAU is an MPI program analyzer. It generates all necessary information during the program execution, so that it can be read after it and displayed by a specialized program.

• 2.25 compiled with GCC and Open MPI
• 2.25 compiled with ICC and Open MPI

use module avail tau to view installed versions.

example :

$ module avail perf/tau

1. Dynamic Instrumentation: No change to your application's source or binary code is necessary. Using the tau_exec command before your executable generates both profile and trace data.
2. Compiler-Based Instrumentation: TAU can also be used to compile your application using wrapper scripts for mpicc, mpicxx, and mpif90. Tau instruments the binary code without changing the source. Using the tau_exec command before the TAU-compiled executable generates profile and trace data. Data is collected on both MPI calls and your application's function calls.

1. Load the needed tau

   $ module load perf/tau/icc

2. Compile

   $ mpicc hello.c -o hello

3. Dynamic instrumentation

   $ mpirun -np $NSLOTS tau_exec ./hello

4. Run TAU's recompiling tool

   $ tau_treemerge.pl

5. After this it will have generated some output files, merge them with the next command

   $ tau2slog2 tau.trc tau.edf -o tau.slog2

6. Now just open the new merged file with the default displaying tool

   $ jumpshot tau.slog2

7. For profiling just call pprof and paraprof programs to view profilers results

For each compiler type there is TAU wrapper, for example:

• tau_cxx.sh for C++ compiler
• tau_f90.sh for Fortarn 90 compiler
• tau_cc.sh fot C compiler

Tau warapper uses $TAU_MAKEFILE to compile programs.

1. Compile programs

   tau_cc.sh hello.c -o hello

2. Run program as usual

   mpirun -np $NSLOTS ./hello

3. Follow steps 4, 5, 6 like for dynamic instrumentation

You can also view profilers information with: pprof or paraprof

Let's profile/trace program (simple Jacobi iteration)

Tracing

$ module load perf/tau/icc
 
$ mpicc jacobi.c -o jacobi
 
$ mpirun -np 4 tau_exec ./jacobi
 
$ tau_treemerge.pl
 
$ tau2slog2 tau.trc tau.edf -o tau.slog2
 
$ jumpshot tau.slog2

Profiling
We need to pack all the profiles.* files in a unique one:

$ paraprof --pack tau.ppk

Now, we can visualize the tau.ppk file by using Paraprof

$ paraprof