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Diffstat (limited to '')
| -rw-r--r-- | src/common/x64/cpu_detect.cpp | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/src/common/x64/cpu_detect.cpp b/src/common/x64/cpu_detect.cpp index 322aa1f08..1a27532d4 100644 --- a/src/common/x64/cpu_detect.cpp +++ b/src/common/x64/cpu_detect.cpp @@ -161,6 +161,22 @@ static CPUCaps Detect() { caps.invariant_tsc = Common::Bit<8>(cpu_id[3]); } + if (max_std_fn >= 0x15) { + __cpuid(cpu_id, 0x15); + caps.tsc_crystal_ratio_denominator = cpu_id[0]; + caps.tsc_crystal_ratio_numerator = cpu_id[1]; + caps.crystal_frequency = cpu_id[2]; + // Some CPU models might not return a crystal frequency. + // The CPU model can be detected to use the values from turbostat + // https://github.com/torvalds/linux/blob/master/tools/power/x86/turbostat/turbostat.c#L5569 + // but it's easier to just estimate the TSC tick rate for these cases. + if (caps.tsc_crystal_ratio_denominator) { + caps.tsc_frequency = static_cast<u64>(caps.crystal_frequency) * + caps.tsc_crystal_ratio_numerator / + caps.tsc_crystal_ratio_denominator; + } + } + if (max_std_fn >= 0x16) { __cpuid(cpu_id, 0x16); caps.base_frequency = cpu_id[0]; |