diff options
Diffstat (limited to 'Source/Core/Common/x64CPUDetect.cpp')
| -rw-r--r-- | Source/Core/Common/x64CPUDetect.cpp | 41 |
1 files changed, 10 insertions, 31 deletions
diff --git a/Source/Core/Common/x64CPUDetect.cpp b/Source/Core/Common/x64CPUDetect.cpp index 87c3d50acd..76ce1af7e5 100644 --- a/Source/Core/Common/x64CPUDetect.cpp +++ b/Source/Core/Common/x64CPUDetect.cpp @@ -3,6 +3,7 @@ #include <cstring> #include <string> +#include <thread> #include "Common/CPUDetect.h" #include "Common/CommonTypes.h" @@ -106,7 +107,6 @@ void CPUInfo::Detect() // Detect family and other misc stuff. bool ht = false; HTT = ht; - logical_cpu_count = 1; if (max_std_fn >= 1) { __cpuid(cpu_id, 0x00000001); @@ -120,9 +120,13 @@ void CPUInfo::Detect() // Detect AMD Zen1, Zen1+ and Zen2 if (family == 23) bZen1p2 = true; - logical_cpu_count = (cpu_id[1] >> 16) & 0xFF; ht = (cpu_id[3] >> 28) & 1; + // AMD CPUs before Zen faked this flag and didn't actually + // implement simultaneous multithreading (SMT; Intel calls it HTT) + // but rather some weird middle-ground between 1-2 cores + HTT = ht && (vendor == CPUVendor::Intel || family >= 23); + if ((cpu_id[3] >> 25) & 1) bSSE = true; if ((cpu_id[3] >> 26) & 1) @@ -200,35 +204,10 @@ void CPUInfo::Detect() bLongMode = true; } - num_cores = (logical_cpu_count == 0) ? 1 : logical_cpu_count; - - if (max_ex_fn >= 0x80000008) - { - // Get number of cores. This is a bit complicated. Following AMD manual here. - __cpuid(cpu_id, 0x80000008); - int apic_id_core_id_size = (cpu_id[2] >> 12) & 0xF; - if (apic_id_core_id_size == 0) - { - if (ht) - { - // New mechanism for modern Intel CPUs. - if (vendor == CPUVendor::Intel) - { - __cpuidex(cpu_id, 0x00000004, 0x00000000); - int cores_x_package = ((cpu_id[0] >> 26) & 0x3F) + 1; - HTT = (cores_x_package < logical_cpu_count); - cores_x_package = ((logical_cpu_count % cores_x_package) == 0) ? cores_x_package : 1; - num_cores = (cores_x_package > 1) ? cores_x_package : num_cores; - logical_cpu_count /= cores_x_package; - } - } - } - else - { - // Use AMD's new method. - num_cores = (cpu_id[2] & 0xFF) + 1; - } - } + // this should be much more reliable and easier + // than trying to get the number of cores out of the CPUID data + // ourselves + num_cores = std::max(std::thread::hardware_concurrency(), 1u); } // Turn the CPU info into a string we can show |