Add x86_64 compute levels as additional system types

When performing distributed builds of machine learning packages, it
would be nice if builders without the required SIMD instructions can
be excluded as build nodes.

Since x86_64 has accumulated a large number of different instruction
set extensions, listing all possible extensions would be unwieldy.
AMD, Intel, Red Hat, and SUSE have recently defined four different
microarchitecture levels that are now part of the x86-64 psABI
supplement and will be used in glibc 2.33:

https://gitlab.com/x86-psABIs/x86-64-ABI
https://lwn.net/Articles/844831/

This change uses libcpuid to detect CPU features and then uses them to
add the supported x86_64 levels to the additional system types. For
example on a Ryzen 3700X:

$ ~/aps/bin/nix -vv --version | grep "Additional system"
Additional system types: i686-linux, x86_64-v1-linux, x86_64-v2-linux, x86_64-v3-linux
This commit is contained in:
Daniël de Kok 2021-02-16 14:32:12 +01:00
parent 4e98f0345c
commit 2de232d2b3
9 changed files with 126 additions and 11 deletions

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@ -9,6 +9,7 @@ CXXFLAGS = @CXXFLAGS@
EDITLINE_LIBS = @EDITLINE_LIBS@ EDITLINE_LIBS = @EDITLINE_LIBS@
ENABLE_S3 = @ENABLE_S3@ ENABLE_S3 = @ENABLE_S3@
GTEST_LIBS = @GTEST_LIBS@ GTEST_LIBS = @GTEST_LIBS@
HAVE_LIBCPUID = @HAVE_LIBCPUID@
HAVE_SECCOMP = @HAVE_SECCOMP@ HAVE_SECCOMP = @HAVE_SECCOMP@
LDFLAGS = @LDFLAGS@ LDFLAGS = @LDFLAGS@
LIBARCHIVE_LIBS = @LIBARCHIVE_LIBS@ LIBARCHIVE_LIBS = @LIBARCHIVE_LIBS@

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@ -218,6 +218,14 @@ LDFLAGS="-lz $LDFLAGS"
# Look for libbrotli{enc,dec}. # Look for libbrotli{enc,dec}.
PKG_CHECK_MODULES([LIBBROTLI], [libbrotlienc libbrotlidec], [CXXFLAGS="$LIBBROTLI_CFLAGS $CXXFLAGS"]) PKG_CHECK_MODULES([LIBBROTLI], [libbrotlienc libbrotlidec], [CXXFLAGS="$LIBBROTLI_CFLAGS $CXXFLAGS"])
# Look for libcpuid.
if test "$machine_name" = "x86_64"; then
PKG_CHECK_MODULES([LIBCPUID], [libcpuid], [CXXFLAGS="$LIBCPUID_CFLAGS $CXXFLAGS"])
have_libcpuid=1
AC_DEFINE([HAVE_LIBCPUID], [1], [Use libcpuid])
fi
AC_SUBST(HAVE_LIBCPUID, [$have_libcpuid])
# Look for libseccomp, required for Linux sandboxing. # Look for libseccomp, required for Linux sandboxing.
if test "$sys_name" = linux; then if test "$sys_name" = linux; then

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@ -91,7 +91,8 @@
gmock gmock
] ]
++ lib.optionals stdenv.isLinux [libseccomp utillinuxMinimal] ++ lib.optionals stdenv.isLinux [libseccomp utillinuxMinimal]
++ lib.optional (stdenv.isLinux || stdenv.isDarwin) libsodium; ++ lib.optional (stdenv.isLinux || stdenv.isDarwin) libsodium
++ lib.optional stdenv.isx86_64 libcpuid;
awsDeps = lib.optional (stdenv.isLinux || stdenv.isDarwin) awsDeps = lib.optional (stdenv.isLinux || stdenv.isDarwin)
(aws-sdk-cpp.override { (aws-sdk-cpp.override {

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@ -3,6 +3,7 @@
#include "archive.hh" #include "archive.hh"
#include "args.hh" #include "args.hh"
#include "abstract-setting-to-json.hh" #include "abstract-setting-to-json.hh"
#include "compute-levels.hh"
#include <algorithm> #include <algorithm>
#include <map> #include <map>
@ -133,24 +134,29 @@ StringSet Settings::getDefaultSystemFeatures()
StringSet Settings::getDefaultExtraPlatforms() StringSet Settings::getDefaultExtraPlatforms()
{ {
StringSet extraPlatforms;
if (std::string{SYSTEM} == "x86_64-linux" && !isWSL1()) if (std::string{SYSTEM} == "x86_64-linux" && !isWSL1())
return StringSet{"i686-linux"}; extraPlatforms.insert("i686-linux");
#if __APPLE__
#if __linux__
StringSet levels = computeLevels();
for (auto iter = levels.begin(); iter != levels.end(); ++iter)
extraPlatforms.insert(*iter + "-linux");
#elif __APPLE__
// Rosetta 2 emulation layer can run x86_64 binaries on aarch64 // Rosetta 2 emulation layer can run x86_64 binaries on aarch64
// machines. Note that we cant force processes from executing // machines. Note that we cant force processes from executing
// x86_64 in aarch64 environments or vice versa since they can // x86_64 in aarch64 environments or vice versa since they can
// always exec with their own binary preferences. // always exec with their own binary preferences.
else if (pathExists("/Library/Apple/System/Library/LaunchDaemons/com.apple.oahd.plist")) { if (pathExists("/Library/Apple/System/Library/LaunchDaemons/com.apple.oahd.plist")) {
if (std::string{SYSTEM} == "x86_64-darwin") if (std::string{SYSTEM} == "x86_64-darwin")
return StringSet{"aarch64-darwin"}; extraPlatforms.insert("aarch64-darwin");
else if (std::string{SYSTEM} == "aarch64-darwin") else if (std::string{SYSTEM} == "aarch64-darwin")
return StringSet{"x86_64-darwin"}; extraPlatforms.insert("x86_64-darwin");
else
return StringSet{};
} }
#endif #endif
else
return StringSet{}; return extraPlatforms;
} }
bool Settings::isExperimentalFeatureEnabled(const std::string & name) bool Settings::isExperimentalFeatureEnabled(const std::string & name)

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@ -0,0 +1,80 @@
#include "types.hh"
#if HAVE_LIBCPUID
#include <libcpuid/libcpuid.h>
#endif
namespace nix {
#if HAVE_LIBCPUID
StringSet computeLevels() {
StringSet levels;
if (!cpuid_present())
return levels;
cpu_raw_data_t raw;
cpu_id_t data;
if (cpuid_get_raw_data(&raw) < 0)
return levels;
if (cpu_identify(&raw, &data) < 0)
return levels;
if (!(data.flags[CPU_FEATURE_CMOV] &&
data.flags[CPU_FEATURE_CX8] &&
data.flags[CPU_FEATURE_FPU] &&
data.flags[CPU_FEATURE_FXSR] &&
data.flags[CPU_FEATURE_MMX] &&
data.flags[CPU_FEATURE_SSE] &&
data.flags[CPU_FEATURE_SSE2]))
return levels;
levels.insert("x86_64-v1");
if (!(data.flags[CPU_FEATURE_CX16] &&
data.flags[CPU_FEATURE_LAHF_LM] &&
data.flags[CPU_FEATURE_POPCNT] &&
// SSE3
data.flags[CPU_FEATURE_PNI] &&
data.flags[CPU_FEATURE_SSSE3] &&
data.flags[CPU_FEATURE_SSE4_1] &&
data.flags[CPU_FEATURE_SSE4_2]))
return levels;
levels.insert("x86_64-v2");
if (!(data.flags[CPU_FEATURE_AVX] &&
data.flags[CPU_FEATURE_AVX2] &&
data.flags[CPU_FEATURE_F16C] &&
data.flags[CPU_FEATURE_FMA3] &&
// LZCNT
data.flags[CPU_FEATURE_ABM] &&
data.flags[CPU_FEATURE_MOVBE]))
return levels;
levels.insert("x86_64-v3");
if (!(data.flags[CPU_FEATURE_AVX512F] &&
data.flags[CPU_FEATURE_AVX512BW] &&
data.flags[CPU_FEATURE_AVX512CD] &&
data.flags[CPU_FEATURE_AVX512DQ] &&
data.flags[CPU_FEATURE_AVX512VL]))
return levels;
levels.insert("x86_64-v4");
return levels;
}
#else
StringSet computeLevels() {
return StringSet{};
}
#endif // HAVE_LIBCPUID
}

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@ -0,0 +1,7 @@
#include "types.hh"
namespace nix {
StringSet computeLevels();
}

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@ -7,3 +7,7 @@ libutil_DIR := $(d)
libutil_SOURCES := $(wildcard $(d)/*.cc) libutil_SOURCES := $(wildcard $(d)/*.cc)
libutil_LDFLAGS = $(LIBLZMA_LIBS) -lbz2 -pthread $(OPENSSL_LIBS) $(LIBBROTLI_LIBS) $(LIBARCHIVE_LIBS) $(BOOST_LDFLAGS) -lboost_context libutil_LDFLAGS = $(LIBLZMA_LIBS) -lbz2 -pthread $(OPENSSL_LIBS) $(LIBBROTLI_LIBS) $(LIBARCHIVE_LIBS) $(BOOST_LDFLAGS) -lboost_context
ifeq ($(HAVE_LIBCPUID), 1)
libutil_LDFLAGS += -lcpuid
endif

7
tests/compute-levels.sh Normal file
View file

@ -0,0 +1,7 @@
source common.sh
if [[ $(uname -ms) = "Linux x86_64" ]]; then
# x86_64 CPUs must always support the baseline
# microarchitecture level.
nix -vv --version | grep -q "x86_64-v1-linux"
fi

View file

@ -38,7 +38,8 @@ nix_tests = \
describe-stores.sh \ describe-stores.sh \
flakes.sh \ flakes.sh \
content-addressed.sh \ content-addressed.sh \
build.sh build.sh \
compute-levels.sh
# parallel.sh # parallel.sh
# build-remote-content-addressed-fixed.sh \ # build-remote-content-addressed-fixed.sh \