Messages in this thread | | | Date | Fri, 24 May 2013 13:34:42 +0200 | From | Lukasz Majewski <> | Subject | Re: [RFC v2 0/3][TESTS] LAB: Support for Legacy Application Booster governor - tests results |
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Hi Viresh,
> On 24 May 2013 14:36, Daniel Lezcano <daniel.lezcano@linaro.org> > wrote: > > I agree with Viresh, a new governor is not necessary here for that. > > Their patchset had two parts.. One is LAB and other is overclocking. > We are trying to solve overclocking for which they never wanted a > new governor. :)
Overclocking can be uses as a standalone feature. However it is crucial for effective LAB operation.
> > > There is the /sys/devices/system/cpufreq/boost option existing for > > x86 platform, why do not reuse it ? It is supposed to do exactly > > what you want to achieve. > > The problem is that it was added at the wrong place.. It should have > been at cpu/cpuX/cpufreq/boost... > > Consider how will we achieve it for big LITTLE.. We know we can > go to overdrive only for a single core in big but for two cores in > LITTLE at the same time.. So, we need that in the location I just > mentioned...
I think that power/thermal envelope here is a key. We can overclock as many cores as we want if we don't exceed limits :-)
Scheduler assignment of tasks to cores and core type decision on which it would run is a different story for b.L.
> > Over that.. I believe it is governor specific too.. It shouldn't be > part of conservative as it should be conservative rather then > aggressive :) > > > IMO, the logic of boosting one core when the other are idle should > > be in the driver itself and certainly not setup by the user, except > > if we consider acceptable the user can burn its board ... :)
Sysfs entry can be read only and governor code can be responsible for enabling overclocking.
Overclocking patch provides API implemented at cpufreq.h file to allow in-kernel overclocking.
> > I didn't get it completely.. So, with the options I gave user can only > say.. boost if required and only when few cores are active. User > can't just set max freq continuously if he wishes..
-- Best regards,
Lukasz Majewski
Samsung R&D Poland (SRPOL) | Linux Platform Group
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