Differences

This shows you the differences between two versions of the page.

--- howto:compile_on_windows [2023/12/01 09:05] – clean krack
+++ howto:compile_on_windows [2023/12/01 14:07] (current) – krack
@@ Line 74: / Line 74: @@
 export OMP_NUM_THREADS=2
 </code>
-The binaries with the file extension ''sopt'' are automatically run with only one OpenMP thread. It is also suggest to use an increased ''OMP_STACKSIZE'' of at least 16 MB
+The binaries with the file extension ''sopt'' are automatically run with only one OpenMP thread.
+It is also suggested to increase the ''OMP_STACKSIZE'' to at least 16 MB
 <code>
 export OMP_STACKSIZE=16M
+ulimit -s 65000
+</code>
+and the ''stacksize'' to 65 MB (check with ''ulimit -a'').
 </code>
@@ Line 152: / Line 157: @@
 cp2k.ssmp
 </code>
-and likewise with ''cp2k.sopt'' or ''cp2k.psmp''.
+and likewise with ''cp2k.sopt''.
+CP2K MPI/OpenMP parallel runs are launched with ''mpirun'' or ''mpiexec'', e.g.
+<code>
+mpiexec -n 4 -genv OMP_NUM_THREADS=2 cp2k.psmp H2O-32.inp
+</code>
+will use 4 MPI ranks with 2 OpenMP threads each (i.e. it will consume 8 CPU cores) to run the input file ''H2O-32.inp'' which can be found in  the cp2k folder ''benchmarks/QS''.
+The ''cp2k.popt'' binary is only MPI parallel and will run just one thread per MPI rank automatically (like ''cp2k.sopt'') which is usually the most efficient usage of CP2K performance-wise if no memory limitation per MPI rank come into play. Therefore, the following commands
+<code>
+mpiexec -n 4 -genv OMP_NUM_THREADS=1 cp2k.psmp H2O-32.inp
+mpiexec -n 4                         cp2k.popt H2O-32.inp
+</code>
+are basically equivalent.
-**Enjoy CP2K !**
+**Enjoy CP2K under Windows!**