On Fri, Dec 8, 2017 at 6:23 AM, Andriy Gapon <a...@freebsd.org> wrote: > On 07/12/2017 12:03, Alexey Dokuchaev wrote: >> On Thu, Nov 30, 2017 at 03:08:49PM -0500, Jung-uk Kim wrote: >>> ... >>> Probably. However, I am just trying to fix my FX-8350 and A10-6800 and >>> I don't have Zen processors to verify the MSRs are actually working on >>> those CPUs. >> >> Ah, that's so lovely, thanks Jung-uk; I feel that our support for AMD >> fam. 15h CPUs is lacking. E.g. only four P-states are reported for my >> A8-5550M, while it supports boosted P-states per BKDG, and reading MSRs >> directly via `sysutils/amdmsrtweaker' reports eight of them (P0 .. P7), >> with three turbo P-states P0 P1 P2. >> >> Since you have A10-6800 you might try to reproduce what I see here with >> A8-5550M. > > I think that the boosted states are supposed to be hidden from the OS. > It may be possible to query them though hardware specific registers, but they > can not be set by software directly anyway.
For most of the modern Intel CPUs, boosted state is _not_ hidden from OS, it normally shows as max_freq+1, e.g. if max_freq is 3400, then the boosted state will have freq 3401. > My impression is that the proper way to observe the boost states is via APERF > / > MPERF MSRs. They are useful for other things, e.g. C0 residency, too. Yeah, that's the only way to observe the current frequency of the cpu; on most of the modern Intel CPUs, P-state just sets the frequency upper limit. Thanks, sephe _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
