CVSROOT: /cvs Module name: src Changes by: mi...@cvs.openbsd.org 2017/10/06 07:33:53
Modified files: sys/arch/amd64/amd64: identcpu.c sys/arch/amd64/conf: files.amd64 sys/arch/amd64/include: cpu.h cpuvar.h sys/dev/acpi : acpihpet.c acpitimer.c Added files: sys/arch/amd64/amd64: tsc.c Log message: Recalibrate TSC timecounter with HPET and PM timer If frequency of an invariant (non-stop) time stamp counter is measured using an independent working timecounter that has a known frequency, we can assume that the measured TSC frequency is as good as the resolution of the timecounter that we use to perform the measurement. This lets us switch from this high quality but expensive source to the cheaper TSC without sacrificing precision on a wide range of modern CPUs. >From Adam Steen <a...@adamsteen.com.au> with tweaks from reyk@ and myself. Tested by brynet@, sthen@ and others, OK mlarkin, sthen