Messages in this thread | | | Date | Tue, 13 May 2014 04:34:16 +0800 | From | Yuyang Du <> | Subject | Re: [RFC PATCH] cpufreq: intel_pstate: Change the calculation of next pstate |
| |
On Tue, May 13, 2014 at 07:16:24AM +0300, Stratos Karafotis wrote: > On 12/05/2014 11:01 μμ, Yuyang Du wrote: > > On Tue, May 13, 2014 at 06:59:42AM +0300, Stratos Karafotis wrote: > >> Hi, > >> > >> On 12/05/2014 10:34 μμ, Yuyang Du wrote: > >>> On Mon, May 12, 2014 at 11:30:03PM +0300, Stratos Karafotis wrote: > >>>> On 09/05/2014 05:56 μμ, Stratos Karafotis wrote: > >>>> > >>>> Next performance state = min_perf + (max_perf - min_perf) * load / 100 > >>>> > >>> Hi, > >>> > >>> This formula is fundamentally broken. You need to associate the load with its > >>> frequency. > >> > >> Could you please explain why is it broken? I think the load should be > >> independent from the current frequency. > > > > Why independent? The load not (somewhat) determined by that? > > > > > > Maybe, in some cases yes. But not always. > For example, please consider a CPU running a tight "for" loop in 100MHz > for a couple of seconds. This produces a load of 100%. > It will produce the same load (100%) in any other frequency.
Still fundamentally wrong, because you are not making a fair comparison ("load" in 100MHz vs. any other freq).
Yuyang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |