Date: Wed, 30 Nov 2005 20:27:52 +0000 From: Marco Calviani <marco.calviani@gmail.com> To: freebsd-acpi@freebsd.org, freebsd-stable@freebsd.org, freebsd-questions@freebsd.org Subject: Re: cpufreq and changing driver Message-ID: <da5cd1900511301227o42e9fa24x@mail.gmail.com> In-Reply-To: <20051130201250.GC4713@poupinou.org> References: <da5cd1900511300337t22728ec8y@mail.gmail.com> <20051130133224.GA4713@poupinou.org> <da5cd1900511300553r40fcb922m@mail.gmail.com> <438DE9D0.6080107@root.org> <20051130201250.GC4713@poupinou.org>
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Hi Bruno,
> The ondemand governor is basically an implemation of the following
> algorithm:
>
> There is a counter, say count.
>
> at each given fixed intervall:
> if (idle less than a watermark) {
> frequency full
> reinitialise count to 10
> } else if (idle more than another watermark) {
> decrement count
> if count is 0 {
> down one step the frequency
> }
> else reinitilize count to 10
>
>
> Note that in the latter case, the down step is performed only
> after 10 such comparison. In other word, intervall is ten times
> larger for the down side than the full frequency one.
>
> This work well when you can perform, say, 20 to 50 transitions per
> second. Otherwise, it is pretty bad.
>
Thanks very much!
But i'm not understanding if this high number of transitions are a
problem from the hardware point of view or from the software
implementation in freeBSD?
Best regards,
MC
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