Raj, Ashok wrote: > You can write 0 to clear it.. actually that's part of what you do even > after taking a sample. > Any idea how long it takes to wrap. I thought I remembered that it was a verrrry long time. But maybe I made that up. ;-)
> > > Cheers, > ashok raj > - Open Source Technology Center > > > > >> -----Original Message----- >> From: tesla-dev-bounces at opensolaris.org >> > [mailto:tesla-dev-bounces at opensolaris.org] On Behalf Of Eric > >> Saxe >> Sent: Friday, June 20, 2008 10:30 AM >> To: Mark Haywood >> Cc: Vinay Devadas; Jim.Britton at Sun.COM; tesla-dev at opensolaris.org >> Subject: Re: [tesla-dev] Turbo Mode Support for Solaris >> >> Mark Haywood wrote: >> >>>> I guess we already discussed this issue before? >>>> Turbo mode is exported as P0 = marked frequency + 1Mhz, >>>> but allow the processors to run faster so that the performance can >>>> be improved up to 20%. Average CPU frequency is doable by the >>>> hardware feedback mechanism. >>>> >>>> >>>> >>> I think that Vinay was asking Jim about the RFE that he added to >>> http://www.opensolaris.org/os/project/tesla/Work/Powertop/ >>> >>> As I think you and I discussed on the alias earlier, the average CPU >>> frequency while in P0 can be determined by strategically placing >>> APERF/MPERF value dtrace probes when transitioning to and from P0. At >>> least that would be the first thing I'd try ... >>> >>> >> We were chatting about this yesterday, and I was wondering what happens >> if we stay at P0 long enough to where APERF/MPERF could wrap? Is that a >> concern...or is the time it would take the counters to wrap >> > sufficiently > >> long? I haven't looked in detail yet, but I was also wondering if >> there's a way to explicitly reset the counters at the beginning of a >> sampling interval to maximize the time-to-wrap (if it is short). >> >> Thanks, >> -Eric >> _______________________________________________ >> tesla-dev mailing list >> tesla-dev at opensolaris.org >> http://mail.opensolaris.org/mailman/listinfo/tesla-dev >> > _______________________________________________ > tesla-dev mailing list > tesla-dev at opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/tesla-dev >
