On Wed, Jun 11, 2014 at 12:42:18PM +0100, Morten Rasmussen wrote: > On Wed, Jun 11, 2014 at 12:02:51PM +0100, Eduardo Valentin wrote: > > Hello, > > > > On Mon, Jun 09, 2014 at 09:22:49AM -0400, Nicolas Pitre wrote: > > > On Mon, 9 Jun 2014, Morten Rasmussen wrote: > > > > > > > On Sat, Jun 07, 2014 at 03:33:58AM +0100, Nicolas Pitre wrote: > > > > > On Fri, 6 Jun 2014, Ingo Molnar wrote: > > > > > > > > > > > In any case, even with turbo frequencies, switching power use is > > > > > > probably an order of magnitude higher than leakage current power > > > > > > use, > > > > > > on any marketable chip, so we should concentrate on being able to > > > > > > cover this first order effect (P/work ~ V^2), before considering > > > > > > any > > > > > > second order effects (leakage current). > > > > > > > > > > Just so that people are aware... We'll have to introduce thermal > > > > > constraint management into the scheduler mix as well at some point. > > > > > Right now what we have is an ad hoc subsystem that simply monitors > > > > > temperature and apply crude cooling strategies when some thresholds > > > > > are > > > > > met. But a better strategy would imply thermal "provisioning". > > > > > > > > There is already work going on to improve thermal management: > > > > > > > > http://lwn.net/Articles/599598/ > > > > > > > > The proposal is based on power/energy models (too). The goal is to > > > > Can you please point me to the other piece of code which is using > > power/energy models too? We are considering having these models within > > the thermal software compoenents. But if we already have more than one > > user, might be worth considering a separate API. > > The link above is to the thermal management proposal which includes a > power model. This one might work better: > > http://article.gmane.org/gmane.linux.power-management.general/45000 > > The power/energy model in this energy-aware scheduling proposal is > different. An example of the model data is in patch 6 (the start of this > thread) and the actual use of the model is in patch 11 and the following > patches. As said below, the two proposals are independent, but there > might be potential for merging the power/energy models once the > proposals are more mature.
Morten, For the power allocator thermal governor, I am aware, as I am reviewing it. I am more interested in other users of power models, a part from thermal subsystem. > > Morten > > > > > > > allocate power intelligently based on performance requirements. > > > > > > Ah, great! I missed that. > > > > > > > While it is related to energy-aware scheduling and I fully agree that it > > > > is something we need to consider, I think it is worth developing the two > > > > ideas in parallel and look at sharing things like the power model later > > > > once things mature. Energy-aware scheduling is complex enough on its > > > > own to keep us entertained for a while :-) > > > > > > Absolutely. This is why I said "at some point". > > > > > > > > > Nicolas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
