4 ms·
Its disappointing that AMD didn't bother to implement the 15H CPUID leaf that Intel added years ago to get the exact CPU TSC frequency. Yet AMD cared enough to
by fsfod 7y ago
Its disappointing that AMD didn't bother to implement the 15H CPUID leaf that Intel added years ago to get the exact CPU TSC frequency. Yet AMD cared enough to add there own instruction(RDPRU) to get the values of APERF and MPERF in user mode.
- vardump 7y agoAs if that matters much in the current TSC frequency disaster... Very few Intel processors implement it completely or at all.
- jart 7y agoIntel claims to implement 15H CPUID but usually leaves the ART crystal HZ in ECX blank, which makes the other fields useless. Invariant timestamps are available on all x86_64 CPUs except K8, but trying to convert them to nanoseconds is an even bigger shit show than clock_gettime.