process wakeups

[Harald Hoyer]

Matthew Garrett wrote:
> On Mon, Jul 14, 2008 at 02:57:56PM -0700, Ulrich Drepper wrote:
> 
>> I would hope the package maintainers can find some time and look at the
>> issues.  Maybe at least document them in a BZ.  I might try to do the
>> latter myself but given the large number of packages involved I'll most
>> likely be able to cover just a few packages.  IMO it should be a release
>> criteria that a program does use polling.
> 
> There are certain situations where polling is inevitable (such as 
> querying hardware for battery status or signal strength, pulling mail, 
> that kind of thing). Applications that do this should do it at 
> relatively low frequency, and where possible (ie, almost always) use 
> g_timeout_add_seconds or equivalent functionality. It's pretty 
> inevitable that we'll have one wakeup a second, and ensuring that all 
> applications that need to be woken during that second are woken at the 
> same time has a significant benefit on power consumption.
> 


g_timeout_add_seconds does not "really" sync globally.

The kernel could schedule a common (across all apps) wakeup time a little bit 
better than g_timeout_add_seconds(), if the application could specify a time 
"range" of how long it would like to approx. sleep. Also g_timeout_add_seconds() 
does not work with select/poll.