[maemo-developers] Quality assurance of "stable" software: my battery drained in few hours

[From: Sivan Greenberg]

On Sun, Jun 6, 2010 at 8:20 PM, Ian Stirling <maemo-devel at mauve.plus.com> wrote:
> Robin Burchell wrote:
>>
>> On Sun, Jun 6, 2010 at 2:23 PM, Ian Stirling <maemo-devel at mauve.plus.com>
>> wrote:
>>>>
>>>> It's pretty hard to find out what's eating the battery on N900. First
>>>> you
>>>> have decide that the battery is being consumed too fast. The default
>>>> charge
>>>> meter occasionally realizes it's very wrong, and rapidly readjusts
>>>> itself,
>>>> giving potential misreadings there. bq27200 certainly helps there,
>>>> though
>>>> there's no "production quality" software available to use it yet. Nokia
>>>> Energy Profiler still shines with its absence ;)
>>>
>>> I'm trying to develop something like this.
>>> An energy profiler.
>>>
>>> The ideal would be 'top' - sorted by power use.
>>> But this is hard. :)
>>
>> You mean, like, powertop? http://en.wikipedia.org/wiki/PowerTOP
>
> No, fairly unlike powertop.
>
> Powertop sorts by wakeups, which is not useless.
>
> Consider a compute intensive task that uses 99.95% of the CPU.
> At the same time, you've got a lightweight task that polls some descriptor
> 10 times a second.
>
> This will appear above the application that's really causing most battery
> drain.
>
> Powertops metric - wakeups per second - is arguably for some loads better
> than top, but it can be horribly misleading for a number of reasons.

Ideally we'd have a few of the profilers each one for its metric or
combine the logic into one process (to be as lightweight) so we'd get
all the metrics in one profiling run.

Sivan