diff --git a/sys/x86/x86/mp_x86.c b/sys/x86/x86/mp_x86.c index 8dd3f90ef59a..ff90366498e1 100644 --- a/sys/x86/x86/mp_x86.c +++ b/sys/x86/x86/mp_x86.c @@ -255,6 +255,22 @@ topo_probe_amd(void) pkg_id_shift = mask_width((cpu_procinfo2 & AMDID_CMP_CORES) + 1); + /* + * Families prior to 16h define the following value as + * cores per compute unit and we don't really care about the AMD + * compute units at the moment. Perhaps we should treat them as + * cores and cores within the compute units as hardware threads, + * but that's up for debate. + * Later families define the value as threads per compute unit, + * so we are following AMD's nomenclature here. + */ + if ((amd_feature2 & AMDID2_TOPOLOGY) != 0 && + CPUID_TO_FAMILY(cpu_id) >= 0x16) { + cpuid_count(0x8000001e, 0, p); + share_count = ((p[1] >> 8) & 0xff) + 1; + core_id_shift = mask_width(share_count); + } + if ((amd_feature2 & AMDID2_TOPOLOGY) != 0) { for (i = 0; ; i++) { cpuid_count(0x8000001d, i, p);