ubuntu-phone team mailing list archive

[Alberto Aguirre <alberto.aguirre@xxxxxxxxxxxxx>]

That will also be the result of the scaling governor. I was surprised too
that arale (Meizu) only has an interactive governor available.
It's quite hard to measure performance consistently and effectively with
such a governor (specially for comparison purposes).

>I'm more concerned about how can we keep phone graphics performing as well
as they do during touches, even when we're not touching them?
I don't think there's escaping the fact that we will need to tune the
governor to match the Ubuntu workload.




On Fri, Aug 14, 2015 at 3:55 AM, Daniel van Vugt <
daniel.van.vugt@xxxxxxxxxxxxx> wrote:

> It's not just frequency either. On arale (Meizu) for example, smoothness
> correlates directly with whether multiple CPU cores are online or not:
>
>   cat /sys/devices/system/cpu/online
>
> Usually the kernel only keeps one core online, which makes Unity8 stutter.
> But if you touch it enough then the second core (out of eight) comes online
> and everything is smooth. I wonder if more aggressive use of threads might
> help...
>
>
>
> On 14/08/15 16:48, Daniel van Vugt wrote:
>
>> Hi all,
>>
>> In testing performance optimisations on various phones, I keep running
>> into an annoying hurdle.
>>
>> Although you can optimise your Mir server/clients in such a way that
>> they're smoother more often, there's an additional variable outside of
>> Mir and Unity that gets in the way. That seems to be frequency scaling
>> done by the kernel. Sometimes on desktops too, but I'm mostly concerned
>> about phones here.
>>
>> I find it suspicious that on some devices you can turn stuttering into
>> smoothness just but touching the screen a lot. But the smoothness soon
>> goes away when you're not touching the screen. In the extreme case, if
>> you're logged into the phone remotely you will also notice the system
>> can become unusably slow when the screen has turned off. That's useful
>> for a real phone's battery life, but it serves to illustrate that the
>> kernel is doing a lot behind the scenes. I'm more concerned about how
>> can we keep phone graphics performing as well as they do during touches,
>> even when we're not touching them?
>>
>> - Daniel
>>
>>
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