Re: power management, ahci link power management and DragonFly

[Alex Hornung <ahornung@xxxxxxxxx>]

On 08/11/2010 15:16, Johannes Hofmann wrote:
> I didn't see those on my thinkpad when adding link power management.
> It looks like a bug. Are you getting those for each request, or just
> when activating it?
> What exact type of thinkpad and harddrive do you use?
My ThinkPad is a T60 8744-HDG with a Hitachi HTS541616J9SA00 drive. And 
it happens for any request, I think. Or maybe for the first one every 
short while.

> I played around with it a bit and to me it seemed that wakeups are not
> that much of a big deal. E.g. decreasing HZ (just for testing) didn't
> gain much. But I might be missing something as everyone in Linux-land
> talks about reducing the wakups and tickless kernels.
Well, I really don't know why we are so power inefficient. Our frequency 
is already rather low at 100 Hz, but something is going on that isn't 
quite right.

Cheers,
Alex