On Nov 18, 2010, at 07:32 , Andriy Gapon wrote: > on 18/11/2010 05:53 George Neville-Neil said the following: >> >> On Nov 16, 2010, at 09:37 , Andriy Gapon wrote: >> >>> >>> Many modern processors provide APERF and MPERF MSRs which allow to easily >>> and >>> reliable calculate average CPU performance level over some interval of time. >>> This also allows to notice things like performance boost, which is generally >>> hidden from software. >>> What would be a proper place to add code that would measure APERF/MPERF >>> ratio? >>> When should trigger such a measurement and over what interval? >>> Ideas? >> >> Can you point me at documentation for this? This sounds a lot like >> hwpmc(4) and I wonder if we can make these available in the same way. > > Actually it feels more cpufreq-ish to me. > This feature is documented in, e.g., Intel Software Developer's Manual volume > 3A, > section 14.2 P-STATE HARDWARE COORDINATION.
Ah, yes, quite right on cpufreq etc. Thanks for the documentation pointer though. Best, George _______________________________________________ freebsd-acpi@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-acpi To unsubscribe, send any mail to "freebsd-acpi-unsubscr...@freebsd.org"