Package: lammps Version: 20240207+dfsg-1.1+b4 Severity: wishlist X-Debbugs-Cc: c...@slerp.xyz
Dear Maintainer, The lammps project has an AMD ROCm backend for hardware acceleration on AMD GPUs. It would be good to enable this functionality. There are two different backends for LAMMP based on AMD ROCm. There is a GPU backend which uses HIP directly and a GPU backend that uses Kokkos. A ROCm-enabled kokkos package is required for the latter and has been requested in Debian Bug #1082813 [1]. The lammps documentation notes that performance is typically better on large simulations with double precision when using Kokkos support [2]. The ROCm libraries packaged for Debian are currently built for gfx803, gfx900, gfx906, gfx908, gfx90a, gfx1010, gfx1030, gfx1100, gfx1101, and gfx1102. They will soon be be built for gfx942 as well. However, kokkos appears to be limited to gfx900, gfx906, gfx908, gfx90a, gfx942, gfx1030, and gfx1100. I supppose the lammps backend that uses kokkos may be limited to fewer architectures than the backend that uses HIP directly. When building for the AMD GPU backend (without kokkos), the following packages are required: hipcc libhipcub-dev And the relevent configuration options include [3]: -DPKG_GPU=ON -DGPU_API=hip -DGPU_PREC=<mixed,single,double> -DHIP_ARCH=<targets> When building for the kokkos backend, the libhipcub-dev package is not required. However, kokkos depends on having an FFT package available. The following packages would be used for the AMD GPU backend with kokkos: hipcc libhipfft-dev And the relevent configuration options include: -DFFT_KOKKOS=hipfft The compiling of GPU code will require the use of hipcc as the C++ compiler. This can be done with CXX=hipcc before calling into CMake. Any options that are incompatible with device code can be restricted to host code by prefixing -Xarch_host. For an example of this, see the rocthrust package [4]. I would suggest adding -DROCPRIM_USE_ARCH_CONVERSION to the DEB_CXXFLAGS_MAINT_PREPEND flags when building either backend. This is a rocprim build option that affects rocthrust and hipcub. It causes gfx902, gfx909, and gfx90c to use gfx900 code paths and causes gfx1031, gfx1032, gfx1033, gfx1034, gfx1035, and gfx1036 to use gfx1030 code paths. It may or may not be sufficient to kokkos support to those architectures, but it will at least be necessary. If you require access to compatible hardware to test this functionality, please reach out privately and I may be able to help. Sincerely, Cory Bloor [1]: https://bugs.debian.org/1082813 [2]: https://docs.lammps.org/Speed_kokkos.html#performance-to-expect [3]: https://docs.lammps.org/Build_extras.html#gpu [4]: https://salsa.debian.org/rocm-team/rocthrust/-/blob/debian/5.7.1-3/debian/rules#L8-10 -- System Information: Debian Release: trixie/sid APT prefers unstable APT policy: (500, 'unstable') Architecture: amd64 (x86_64) Kernel: Linux 6.10.11-amd64 (SMP w/32 CPU threads; PREEMPT) Locale: LANG=C, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE not set Shell: /bin/sh linked to /usr/bin/dash Init: unable to detect Versions of packages lammps depends on: ii lammps-data 20240207+dfsg-1.1 ii libc6 2.40-3 ii libgcc-s1 14.2.0-5 ii liblammps0t64 20240207+dfsg-1.1+b4 ii libopenmpi3t64 4.1.6-13.3 ii libstdc++6 14.2.0-5 ii mpi-default-bin 1.17 Versions of packages lammps recommends: ii lammps-doc 20240207+dfsg-1.1 Versions of packages lammps suggests: pn openkim-models <none> ii python3 3.12.6-1 -- no debconf information
