ubuntu-phone team mailing list archive

[Chunsang Jeong <chunsang.jeong@xxxxxxxxxxxxx>]

On Sat, Aug 15, 2015 at 12:32 AM, Alberto Aguirre <
alberto.aguirre@xxxxxxxxxxxxx> wrote:

> 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?
>>>
>>>
I'm not sure these are what you want to, but if you're testing on Arale,
you can enable cpus by
 /proc/hps/num_base_perf_serv [# of little] [# of bigs]
   ex) sudo /proc/hps/num_base_perf_serv 2 2 (2 littles and 2 bigs)
and also can set gpu with the max freq by
  echo 0 > /sys/module/pvrsrvkm/parameters/gpu_dvfs_enable
(though I'm recommending this only for testing.)

- Daniel
>>>
>>>
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-- 
Chunsang(Paul) Jeong