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Use feature_level field from libcpuid (#12674)

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Close #11375

Co-authored-by: John Ericson <git@JohnEricson.me>
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The Tumultuous Unicorn Of Darkness 2025-03-20 18:11:55 +01:00 • committed by GitHub
parent c97f779dbb
commit 83ec81789a
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2 changed files with 14 additions and 53 deletions
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65
src/libutil/compute-levels.cc
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@ -2,6 +2,7 @@
#if HAVE_LIBCPUID
#include <libcpuid/libcpuid.h>
#include <map>
#endif
namespace nix {
@ -10,61 +11,21 @@ namespace nix {
StringSet computeLevels() {
StringSet levels;
struct cpu_id_t data;
if (!cpuid_present())
const std::map<cpu_feature_level_t, std::string> feature_strings = {
{ FEATURE_LEVEL_X86_64_V1, "x86_64-v1" },
{ FEATURE_LEVEL_X86_64_V2, "x86_64-v2" },
{ FEATURE_LEVEL_X86_64_V3, "x86_64-v3" },
{ FEATURE_LEVEL_X86_64_V4, "x86_64-v4" },
};
if (cpu_identify(NULL, &data) < 0)
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");
for (auto & [level, levelString] : feature_strings)
if (data.feature_level >= level)
levels.insert(levelString);
return levels;
}