On Mon, 6 Jan 2014 06:39:38 +0600 Roman Mamedov <[email protected]> wrote:
> On Mon, 6 Jan 2014 00:00:00 +0200 > Siarhei Siamashka <[email protected]> wrote: > > > A better solution is to really ramp up the CPU to the maximum clock > > speed if we have some external power source connected (ACIN or VBUS). > > Adhering to the "principle of least surprise", it makes sense to fork > > the "ondemand" governor with some new name and make it the default. > > A new governor (and a platform-specific one, no less) is unlikely to ever be > mainlined. It's a bit too early to talk about mainlining. We need to solve the problem at hand before planning too far ahead. I proposed this particular solution with the upgrade path for sunxi-3.4 in mind. Also I don't pretend to know much about power management. But the current default cpufreq performance is simply unacceptable and something has to be done about it. Enough is enough. > Try mainlining those "fantasy" or "interactive", you'll more likely > be <del>laughed out of the building</del> politely pointed to all the tunables > of "ondemand", some of which I just listed in my other E-Mail. Well, it is the primary responsibility of the kernel to provide an efficient way to use the hardware. If the kernel fails to handle this efficiently for any reasons, then it is doing a poor job and needs to be improved. And the kernel is indeed always evolving. New things are being introduced whenever they are justified. And for example, do you remember things like hyper-threading or turbo boost? Why haven't those dudes been <del>laughed out of the building</del> politely asked to design the hardware so that it plays nice with the existing kernel without any need to introduce anything new? But why am I even explaining these obvious things? > If you *really* want to react to power events, there is no reason a userspace > program can't change max/min_frequency of the ondemand governor, or even > switch between ondemand and performance as the power situation allows; it > could > be either a daemon or a oneshot script called from udev(?), if changes are > only > required on plugging/unplugging of power source. In fact I think there should > be something like that already (designed for laptops). AFAIK on the x86 laptops at least part of this functionality is handled by the BIOS and ACPI. Which makes them a little bit different from ARM hardware. In any case, I don't like the idea of forcing the userland to take special care of sunxi specific power management when this can be better done in the kernel. How the hell are you going to package it for many different linux distributions? -- Best regards, Siarhei Siamashka -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
