Re: [Task Scheduler] scheduling flexibility

Resending for John. He just switched to a new account and it's stuck in
moderation.

Thanks for all replies so far. I'm very interested in exploring John's
suggestions further.

Regards,

Michael


On Tue, Nov 5, 2013 at 2:26 PM, John Mellor <johnme@google.com> wrote:

> Actually, I think we might need to go further than this. Allowing web apps
> to request to be woken up with precise scheduling seems very dangerous from
> a battery life perspective. Would it be possible to split this API into two
> use cases?
>
> 1. An API for precise scheduling, which **requires you to show a
> user-visible notification** to prevent developers from abusing it. For
> use by calendar notifications, alarm clocks, etc. Could be an extension of Web
> Notifications <http://www.w3.org/TR/notifications/>.
>
> 2. An API for inexact scheduling (e.g. background syncing). For example,
> instead of asking to be woken up at a specific DOMTimeStamp, you would just
> give an optional minimum time delay; the system would guarantee not to wake
> you up before that, but would choose any convenient moment afterwards. Most
> apps would just choose the smallest time delay we offer them (which is
> fine, as the convenient moment mechanism would throttle them), but
> sometimes an app knows that there's no point in running until some point in
> the future, which is when they would provide a non-zero minimum time delay.
>
> Possible heuristics that the system might use to decide what is convenient
> time for background execution include:
> - batching requests together with other apps
> - being on WiFi
>  - being plugged in to a charger
> - the screen being on (or device being awake for some other reason)
> - the network being active
> - the user not being asleep
> - learning at what times of day each app gets used, and prioritizing
> syncing etc shortly before the app is likely to be used
> - learning in what locations each app gets used, similarly
> - how recently/frequently the app has been used
> - how recently the device was last used
>
> Of course the heuristics would be implementation-defined, so
> implementations can optimize battery life without having to update the spec
> each time.
>
> Thanks,
> John
>
>
> On Tue, Nov 5, 2013 at 1:35 PM, Michael van Ouwerkerk <
> mvanouwerkerk@chromium.org> wrote:
>
>> How do people feel about allowing for scheduling flexibility in the Task
>> Scheduler API? The goal of this feature would be to save battery power. If
>> the system has flexibility about when to precisely run a task, it could
>> batch multiple tasks together, or only run tasks when the device is awake.
>> This way, we could avoid waking up devices too frequently.
>>
>> Some use cases require precise scheduling e.g. an alarm in the morning,
>> or a cooking timer. But there are many tasks that are much less time
>> sensitive, these could be scheduled flexibly e.g. syncing a news feed or
>> auto-updating to a new version.
>>
>> Any comments? My apologies if this issue has been discussed previously.
>>
>> Regards,
>>
>> Michael van Ouwerkerk
>>
>>
>