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, GeorgeReceived on Thu Nov 18 2010 - 13:15:54 UTC
This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:40:09 UTC