PAR Lecture 21, Thurs Apr 6

1   OpenMP on the mic

1. OpenMP is now running on the mic (Xeon Phi).

2. Setup envars thus (assuming you're using bash or zsh):

   source /opt/intel/bin/iccvars.sh arch intel64
   export SINK_LD_LIBRARY_PATH=/opt/intel/lib/mic
   

3. To compile on parallel for running on parallel:

   icpc -fopenmp sum_reduc2.cc -o sum_reduc2
   

4. Run it on parallel thus:

   ./sum_reduc2
   

5. To cross compile on parallel for running on mic0:

   icpc -mmic -fopenmp sum_reduc2.cc -o sum_reduc2-mic
   

6. Run it natively on mic0 thus:

   micnativeloadex sum_reduc2-mic
   

7. It is also possible to have an OpenMP program on parallel.ecse execute parallel threads on mic0:

   #pragma offload target (mic)
     {
     #pragma omp parallel
       {
       ...
       }
     }
   

   See /parallel-class/mic/stackoverflow/hello.c

8. Compile it thus:

   icc -fopenmp hello.c -o hello
   

   Note that there is no -mmic.

9. Run it thus:

   ./hello
   

10. /parallel-class/mic/stackoverflow/hello_omp.c shows a different syntax.

11. Degrees of parallelism: See slide 12 of https://software.intel.com/sites/default/files/managed/87/c3/using-nested-parallelism-in-openMP-r1.pdf