Re: suspend2 merge (was Re: [Suspend2-devel] Re: CFS and suspend2:hang in atomic copy)

From: Josh Triplett
Date: Sat Apr 28 2007 - 21:35:09 EST


Matthew Garrett wrote:
> On Sat, Apr 28, 2007 at 12:15:50PM -0700, David Lang wrote:
>> with dynaticks now in the kernel it may even be possible to have the idle
>> process decide that the next event is far enough away that it should
>> suspend-to-ram until that point.
>
> This would be ideal (and it's broadly what the OLPC guys are aiming for,
> I think), but on most platforms you're looking at at least a second or
> so to resume. As far as I know, we're still looking at ~60 ticks a
> second at best for an average desktop, so that's not going to be a win.

As long as the system has a clear idea of how long it will take to resume, it
can schedule a wakeup for a reasonable amount of time before that. Ideally, a
completely unused system might not need a tick for several seconds. However,
I agree that it doesn't make sense to add such functionality to the kernel
until someone can show a system that can actually wait that long between
ticks.

- Josh Triplett
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