6. FAQ

Frequently Asked Questions

• What is the minimum version for GCC?
• Spack installation fails. What should I do?
• Does Spack install HDF5 VFD for Hermes?
• Will Google OR-Tools version 8.0 or above work?
• Can I run Hermes on Mac?
• Does Hermes run on Linux only?
• Can I run Hermes on Chameleon JupyterLab Server?
• Why do I get mercury->fatal error when I use rpc_protocol = "ofi+verbs"; in configuration file?
• Why does CTest fail for Test #39 hermes_mpiio_adapter_test2_async?
• Why does MPI Adapter fail to compile?

What is the minimum version for GCC?

GCC 11. Hermes requires C++17 features that are only available since GCC 7.3. C++17 support is enabled by default in GCC 11; it can be explicitly selected in earlier versions with the -std=c++17 command-line flag or -std=gnu++17 to enable GNU extensions as well. See C++17 Support in GCC for the details. Use spack install gcc first if your system has GCC 4. It will install GCC 12.2.0 by default. Then, run spack compiler find to use the newly installed gcc.

Spack installation fails. What should I do?

If Python throws AttributeError: 'NoneType' object has no attribute 'version' during spack installation,

1. try add -d option for spack -d install hermes.
2. try to remove these two packages:
   • mochi-spack-packages/packages/flamestore
   • mochi-spack-packages/packages/py-mochi-tmci
3. try spack install or-tools ^[email protected] if OR-Tools installation fails.
   • gcc-11.2 can't build [email protected].

Does Spack install HDF5 VFD for Hermes?

Yes. To build it with Spack, use $spack install hermes+vfd.

To use the latest 1.13 development version of HDF5, add ^[email protected] (e.g., $spack install hermes+vfd ^[email protected]).

Can I run Hermes on Mac?

No. macOS lacks several system calls that Hermes components use:

• fopen64 / fseeko64
• O_DIRECT / O_TMPFILE
• gethostbyname_r
• _STAT_VER

Does Hermes run on Linux only?

Yes. Hermes uses the fixed /proc code:

inline std::string GetFilenameFromFD(int fd) {
  char proclnk[kMaxPathLen];
  char filename[kMaxPathLen];
  snprintf(proclnk, kMaxPathLen, "/proc/self/fd/%d", fd);
  size_t r = readlink(proclnk, filename, kMaxPathLen);
  filename[r] = '\0';
  return filename;
}

Can I run Hermes on Chameleon JupyterLab Server?

Maybe. However, installation with Spack will fail due to timeout. For older (< 0.8) Hermes, Google OR-Tools installation will fail.

Why do I get mercury->fatal error when I use rpc_protocol = "ofi+verbs"; in configuration file?

Such error occurs when libfabric is not compiled with verbs support. Try spack install hermes ^libfabric fabrics=rxm,sockets,tcp,udp,verbs.

Why does MPI Adapter fail to compile?

Hermes supports both MPICH and OpenMPI.

Please make sure that you invoke the right MPI option.

option(HERMES_MPICH "Specify that this a MPICH build" OFF)
option(HERMES_OPENMPI "Specify that this a OpenMPI build" OFF)

For example, if you use -DHERMES_MPICH=ON, use spack install mpi ^mpich to install mpi. Load it with spack load mpi.