HI Darin,
On Oct 3, 2008, at 1:22 PM, Darin Fisher wrote:
On Fri, Oct 3, 2008 at 3:10 AM, Rob Burns <[EMAIL PROTECTED]> wrote:
Hi Darin,
On Oct 3, 2008, at 9:37 AM, Darin Fisher wrote:
On Thu, Oct 2, 2008 at 10:36 PM, Maciej Stachowiak <[EMAIL PROTECTED]>
wrote:
On Oct 2, 2008, at 10:09 PM, Darin Fisher wrote:
On Thu, Oct 2, 2008 at 9:58 PM, Maciej Stachowiak <[EMAIL PROTECTED]>
wrote:
(I don't understand your comment about not having to have it on
all the time. Surely if a page is asking for a fast setTimeout
repeatedly, it would be on "all the time.")
My understanding is that timeBeinPeriod(1) is currently on all the
time in Chrome, even when no short-delay timers are currently
pending, thus leading to constant greater power consumption. But
there is no need for it to be on when there are not fast timers
pending. See WebCore/platform/win/SharedTimerWin.cpp. I think that
is a technically better approach than switching based on power
management state. Feedback welcome, though, and perhaps you will
still come to a different conclusion.
I think that is a good idea too, but it doesn't help when a fast
setInterval is active.
That is true. With the webkit.org version of SharedTimerWin,
though, you can at least close the problematic tab when you hear
your fan spin up and stop suffering any power drain. It may be that
running slower is a better option.
Yeah, that's the trade off. Close the offending tab or let it run,
but more slowly.
Another option, would be to halt timers for all unexposed tabs
(i.e., tabs in windows that are not the frontmost tab). Are there
use-cases or sites that would break with such behavior? The reason I
raise this option is that the loaded page represents important state
to the user, but when it is buried on a window, it is probably not
necessary for it to be actively responding to timer callbacks.
Closing the tab saves battery life, but burying the tab behind
another tab would be preferable for the user (a mobile user that may
not be online when that important state represented by the page
loaded in the tab is sought again).
Take care,
Rob
It's a good question. I suspect though that it could break sites.
Imagine a calendar application that wishes to periodically wake up
to see if it should put up an alert to notify you of an upcoming
event. Such a feature probably requires the ability to run a timer.
Yes, understood. But this example also requires javascript enabled. If
a user disables javascript this web app will not work either. I'm
suggesting WebKit could allow more finegrained control by allowing
javascript enabled, but timers disabled.
Also this example illustrates how an author of such a calendar web app
may use setTimeout as a polling device rather than using an event-
based approach where the application simply sets event timers for
those alerts. By allowing greater control over disabling setTimeout,
the authoring community will be forced to learn about better
approaches to authoring such a web app. Obviously this stuff won't
happen tomorrow, but we have to take a long view of it from time to
time and think about what we can do to get there.
Take care,
Rob
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