When running MPI+OpenMP hybrid code with the Intel Classic Compiler and MVAPICH 3.0, you may encounter the following warning message from hwloc:
**************************************************************************** * hwloc 2.7.1rc1-git received invalid information from the operating system. * * Failed with: intersection without inclusion * while inserting Group0 (cpuset 0x00000001,0x01010101,0x01010101,0x01010101) at Package (P#0 cpuset 0x55555555,0x55555555,0x55555555) * coming from: linux:sysfs:numa * * The following FAQ entry in the hwloc documentation may help: * What should I do when hwloc reports "operating system" warnings? * Otherwise please report this error message to the hwloc user's mailing list, * along with the files generated by the hwloc-gather-topology script. * * hwloc will now ignore this invalid topology information and continue. ****************************************************************************
This is caused by the fact that the version of hwloc in MVAPICH 3.0 is 2.4.1, which does not match the hwloc 2.7.1rc1-git used in the Intel OpenMP library (iomp5). We have tested and observed no performance issues on a few applications; however, it may impact your case due to potential locality issues. If you encounter any problems, please consider using MVAPICH 3.0 with other compilers such as oneAPI or GCC.
Affected versions
mvapich/3.0 and above
Workaround
If you encounter any problems, please consider using MVAPICH 3.0 with other compilers such as oneAPI or GCC.
