Li, Aubrey wrote: > Mark.Haywood wrote: > > >> Li, Aubrey wrote: >> >>> Firstly, many thanks to report this bug, :-) >>> >>> Before we setup powertop bug track system on defect.opensolaris.org, >>> can we report bug to the mailing list first? >>> >>> my comments about this bug: >>> >>> This is a very good raise-up, really. But I think it'd better to >>> place this bug into Todo list. Currently kernel doesn't support any >>> mechanism to obtain the frequency in the "turbo mode". So, powertop >>> can't report any related info. Actually hardware feedback machanism >>> exists on the processor, We need to enable it. >>> >>> >> It is true that the APERF/MPERF hardware feedback mechanism >> can help to >> identify that a processor has been in "turbo mode". But unless I'm >> mistaken there is no guarantee that when the processor is in >> Turbo Mode >> that APERF/MPERF will catch it. Among other things, it would >> depend upon >> your polling interval - which currently is pretty long. >> > > Can't we assume the processor is in turbo mode when we are in > P0 = (market frequency) + 1Mhz? >
I don't think that the processor being at P0 guarantees that it is in turbo mode. It means that the processor should operate no lower than market frequency and if the circumstances present themselves, then the hardware might overclock the processor for some amount of time. > >> What exactly would powertop report about 'turbo mode'? Amount of time >> spent in "turbo mode"? I think a metric like that is bound to be >> incorrect given the current hardware support isn't it? >> > > If I understand correctly, the bug reporter want to know the average > frequency > in turbo mode(P0) in a sampling period, if hardware support it. > This doesn't make much sense to me. A processor is likely (though maybe not with the current Solaris implementation), to switch in and out of P0 many times during a (powertop defined?) polling period. > Thanks, > -Aubrey > > _______________________________________________ > tesla-dev mailing list > tesla-dev at opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/tesla-dev >
