Messages in this thread | | | Subject | Re: Battery class driver. | From | Benjamin Herrenschmidt <> | Date | Tue, 24 Oct 2006 15:43:42 +1000 |
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On Tue, 2006-10-24 at 04:53 +0100, Matthew Garrett wrote: > On Tue, Oct 24, 2006 at 01:48:27PM +1000, Benjamin Herrenschmidt wrote: > > On Tue, 2006-10-24 at 04:27 +0100, Matthew Garrett wrote: > > > > Reading the battery status has the potential to call an SMI that might > > > take an arbitrary period of time to return, and we found that having > > > querying at around the 1 second mark tended to result in noticable > > > system performace degredation. > > > I think it's up to the backend to poll more slowly and cache the results > > on those machines then. > > The kernel backend or the userspace backend? We need to decide on > terminology :)
The kernel. Userspace don't have to know the details of how hard it is for the backend to fetch the data imho.
> There's no good programmatic way of determining how long > a query will take other than doing it and looking at the result. I guess > we could do that at boot time.
Ben.
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