Comment by decisiveness
9 years ago
To quote the Intel Developer Instructions[1] on the HTT flag:
>A value of 0 for HTT indicates there is only a single logical processor in the package and software should assume only a single APIC ID is reserved. A value of 1 for HTT indicates the value in CPUID.1.EBX[23:16] (the Maximum number of addressable IDs for logical processors in this package) is valid for the package.
UPDATE: It appears these flags refer to each initial APIC ID, so it seems the HTT flag value should be 0 in all cases where the overall processor:thread ratio is 1, suggesting there might either be incorrect information in the CPUID instruction for some Intel CPUs or the kernel is not correctly evaluating CPUID.1.EBX[23:16].
Hopefully, someone more versed in CPUs can correct me here.
[1]https://www.intel.com/content/www/us/en/architecture-and-tec...
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