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stick to NEON when building GROMACS on ARM CPUs, even when SVE is supported #3870

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stick to NEON when building GROMACS on ARM CPUs, even when SVE is supported #3870

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0a3b9bb
stick to NEON when building GROMACS on ARM CPUs, even when SVE is sup…
boegel Aug 5, 2025
a0bbcdc
improve warning message to motivate sticking to NEON even though SVE …
boegel Aug 12, 2025
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14 changes: 13 additions & 1 deletion easybuild/easyblocks/g/gromacs.py
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Original file line number Diff line number Diff line change
Expand Up @@ -50,7 +50,7 @@
from easybuild.tools.filetools import copy_dir, find_backup_name_candidate, remove_dir, which
from easybuild.tools.modules import get_software_libdir, get_software_root, get_software_version
from easybuild.tools.run import run_shell_cmd
from easybuild.tools.systemtools import X86_64, get_cpu_architecture, get_cpu_features, get_shared_lib_ext
from easybuild.tools.systemtools import AARCH64, X86_64, get_cpu_architecture, get_cpu_features, get_shared_lib_ext
from easybuild.tools.toolchain.compiler import OPTARCH_GENERIC
from easybuild.tools.utilities import nub
from easybuild.tools.version import VERBOSE_VERSION as EASYBUILD_VERSION
Expand Down Expand Up @@ -377,6 +377,18 @@ def configure_step(self):
else:
self.cfg.update('configopts', "-DGMX_SIMD=%s" % gmx_simd)

# stick to NEON even if SVE is supported,
# see https://gitlab.com/gromacs/gromacs/-/issues/5284;
cpu_arch = get_cpu_architecture()
if cpu_arch == AARCH64 and 'DGMX_SIMD' not in self.cfg['configopts']:
cpu_features = get_cpu_features()
if 'sve' in cpu_features:
self.cfg.update('configopts', "-DGMX_SIMD=ARM_NEON_ASIMD")
# print warning, since this may need to be revised for future GROMACS versions
msg = "Sticking to NEON even though SVE is supported to improve performance, "
msg += "see https://gitlab.com/gromacs/gromacs/-/issues/5284"
print_warning(msg, log=self.log)

# set regression test path
prefix = 'regressiontests'
if any([src['name'].startswith(prefix) for src in self.src]):
Expand Down