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Fix Ryzen core count calculation

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Close X0rg/CPU-X#86
This commit is contained in:
Xorg 2018-11-03 21:30:01 +01:00
commit 3a8343c77c
2 changed files with 107 additions and 2 deletions
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9
libcpuid/recog_amd.c
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@ -381,8 +381,13 @@ static void decode_amd_number_of_cores(struct cpu_raw_data_t* raw, struct cpu_id
}
if (data->flags[CPU_FEATURE_HT]) {
if (num_cores > 1) {
if (data->ext_family >= 23)
num_cores /= 2; // e.g., Ryzen 7 reports 16 "real" cores, but they are really just 8.
if ((data->ext_family >= 23) && (raw->ext_cpuid[0][0] >= 30))
/* Ryzen 3 has SMT flag, but in fact cores count is equal to threads count.
Ryzen 5/7 reports twice as many "real" cores (e.g. 16 cores instead of 8) because of SMT. */
/* On PPR 17h, page 82:
CPUID_Fn8000001E_EBX [Core Identifiers][15:8] is ThreadsPerCore
ThreadsPerCore: [...] The number of threads per core is ThreadsPerCore+1 */
num_cores /= ((raw->ext_cpuid[30][1] >> 8) & 0xff) + 1;
data->num_cores = num_cores;
data->num_logical_cpus = logical_cpus;
} else {