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#
# This file is part of the GROMACS molecular simulation package.
#
# Copyright 2012- The GROMACS Authors
# and the project initiators Erik Lindahl, Berk Hess and David van der Spoel.
# Consult the AUTHORS/COPYING files and https://www.gromacs.org for details.
#
# GROMACS is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public License
# as published by the Free Software Foundation; either version 2.1
# of the License, or (at your option) any later version.
#
# GROMACS is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with GROMACS; if not, see
# https://www.gnu.org/licenses, or write to the Free Software Foundation,
# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# If you want to redistribute modifications to GROMACS, please
# consider that scientific software is very special. Version
# control is crucial - bugs must be traceable. We will be happy to
# consider code for inclusion in the official distribution, but
# derived work must not be called official GROMACS. Details are found
# in the README & COPYING files - if they are missing, get the
# official version at https://www.gromacs.org.
#
# To help us fund GROMACS development, we humbly ask that you cite
# the research papers on the package. Check out https://www.gromacs.org.
# - Check the username performing the build, as well as date and time
#
# gmx_detect_simd(_suggested_simd)
#
# Try to detect CPU features and suggest a SIMD instruction set
# that fits the current CPU. This should work on all architectures
# where we are not cross-compiling; depending on the architecture the
# detection will either use special assembly instructions (like cpuid),
# preprocessor defines, or probing /proc/cpuinfo on Linux.
#
# Sets ${_suggested_simd} in the parent scope if GMX_SIMD is not set
# (e.g. by the user, or a previous run of CMake).
# The string is converted to uppercase for compatibility with
# gmx_option_multichoice() user input parsing.
#
# we rely on inline asm support for GNU!
include(gmxTestInlineASM)
# Ensure things like GMX_TARGET_X86 are available
include(gmxDetectTargetArchitecture)
gmx_detect_target_architecture()
include(gmxDetectCpu)
include(gmxDetectAvx512FmaUnits)
function(gmx_suggest_simd _suggested_simd)
if (NOT SUGGEST_SIMD_QUIETLY)
message(STATUS "Detecting best SIMD instructions for this CPU")
endif()
# Prepare a default suggestion
set(OUTPUT_SIMD "None")
# Detect CPU features and place the string in CPU_DETECTION_FEATURES
# Note that we are NOT limited to x86.
gmx_run_cpu_detection(features)
if (DEFINED CPU_DETECTION_FEATURES)
# Make a concrete suggestion of SIMD level if a feature flag
# matches. Make sure that the match strings below work even if
# the feature is first or last.
set(CPU_DETECTION_FEATURES " ${CPU_DETECTION_FEATURES} ")
if(GMX_TARGET_X86)
gmx_run_cpu_detection(brand)
if(CPU_DETECTION_FEATURES MATCHES " avx512f ")
if(CPU_DETECTION_BRAND MATCHES "Intel")
gmx_detect_avx_512_fma_units(NUMBER_OF_AVX_512_FMA_UNITS)
if(NUMBER_OF_AVX_512_FMA_UNITS EQUAL 2)
set(OUTPUT_SIMD "AVX_512")
elseif(NUMBER_OF_AVX_512_FMA_UNITS EQUAL 1)
if (NOT SUGGEST_SIMD_QUIETLY)
message(STATUS "This is an Intel CPU with only 1 AVX-512 FMA unit, so AVX2 will be faster.")
endif()
set(OUTPUT_SIMD "AVX2_256")
else()
if (NOT SUGGEST_SIMD_QUIETLY)
message(STATUS "Could not run code to detect number of AVX-512 FMA units - assuming 2.")
endif()
set(OUTPUT_SIMD "AVX_512")
endif()
else()
# Non-Intel vendor with AVX-512 presently means AMD,
# and this far AVX-512 is always faster on AMD, even with a single FMA unit.
set(OUTPUT_SIMD "AVX_512")
endif()
elseif(CPU_DETECTION_FEATURES MATCHES " avx2 ")
if(CPU_DETECTION_BRAND MATCHES "AMD")
gmx_run_cpu_detection(family)
gmx_run_cpu_detection(model)
set(ZEN1_MODELS 1 17 8 24)
if("${CPU_DETECTION_FAMILY}" STREQUAL "23" AND "${CPU_DETECTION_MODEL}" IN_LIST ZEN1_MODELS)
# Zen/Zen+, where 128-bit AVX2 will be faster
set(OUTPUT_SIMD "AVX2_128")
else()
# Zen2 or later, where 256-bit AVX2 should be faster
set(OUTPUT_SIMD "AVX2_256")
endif()
else()
# not AMD
set(OUTPUT_SIMD "AVX2_256")
endif()
elseif(CPU_DETECTION_FEATURES MATCHES " avx ")
if(CPU_DETECTION_FEATURES MATCHES " fma4 ")
# AMD that works better with avx-128-fma
set(OUTPUT_SIMD "AVX_128_FMA")
else()
# Intel
set(OUTPUT_SIMD "AVX_256")
endif()
elseif(CPU_DETECTION_FEATURES MATCHES " sse4.1 ")
set(OUTPUT_SIMD "SSE4.1")
elseif(CPU_DETECTION_FEATURES MATCHES " sse2 ")
set(OUTPUT_SIMD "SSE2")
endif()
else()
if(CPU_DETECTION_FEATURES MATCHES " vsx ")
set(OUTPUT_SIMD "IBM_VSX")
elseif(CPU_DETECTION_FEATURES MATCHES " sve ")
set(OUTPUT_SIMD "ARM_SVE")
elseif(CPU_DETECTION_FEATURES MATCHES " neon_asimd ")
set(OUTPUT_SIMD "ARM_NEON_ASIMD")
endif()
endif()
if (NOT SUGGEST_SIMD_QUIETLY)
message(STATUS "Detected best SIMD instructions for this CPU - ${OUTPUT_SIMD}")
endif()
else()
if (NOT SUGGEST_SIMD_QUIETLY)
message(STATUS "Detection for best SIMD instructions failed, using SIMD - ${OUTPUT_SIMD}")
endif()
endif()
set(${_suggested_simd} "${OUTPUT_SIMD}" PARENT_SCOPE)
set(SUGGEST_SIMD_QUIETLY TRUE CACHE INTERNAL "Be quiet during future construction of SIMD suggestions")
endfunction()
function(gmx_detect_simd _suggested_simd)
if(GMX_SIMD STREQUAL "AUTO")
gmx_suggest_simd(${_suggested_simd})
string(TOUPPER "${${_suggested_simd}}" ${_suggested_simd})
set(${_suggested_simd} ${${_suggested_simd}} PARENT_SCOPE)
endif()
endfunction()
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