[PATCH] ARM: multi_v7_defconfig: major refresh

Amit Kucheria
2014-08-08T18:37:50Z

On Fri, Aug 8, 2014 at 11:42 PM, Kevin Hilman <khilman@linaro.org> wrote:
> Olof Johansson <olof@lixom.net> writes:
>
>>
>> At the end of the day, b.L switcher has predictable user behavior, while
>> running with assymetric SMP does not.
>
> What is unpredictable? Perhaps sub-optimal, but I don't see what's any
> more unpreditable about it than normal SMP.
>
>> Until the scheduler work has been done,
>> it is significantly better to enable the switcher instead of SMP on these
>> platforms.
>>
>> Once the scheduler work has come further, we can switch over. But not until
>> then.
>
> I think the upstream defconfigs should facilitate the broader testing of
> the scheduler work by having the swticher disabled.

I thought the upstream defconfigs were meant to make machines work out
of the box. Any development effort can surely tweak the configs to
their needs.

> By enabling the switcher (and the corresponding cpufreq switcher driver)
> by default, we're now actually making one more obstacle for broader
> testing of the generic scheduling on all cores.

Actually, there might some advantages to turning on the switcher.
1. The performance/power numbers of the b.L switcher is the minimum
we need to achieve on a scheduler-driven b.L system. It establishes a
baseline. Shame on us working on EAS if the switcher does better.
2. The switcher exercises the cpufreq drivers quite a bit. So any
niggles will be ironed out on platforms where it hasn't been well
tested.

Regards,
Amit