Re: 2.6.25 regression: powertop says 120K wakeups/sec

[Andrew Morton <akpm@linux-foundation.org>]

On Sat, 22 Mar 2008 13:24:54 -0700 David Brownell <david-b@pacbell.net> wrote:

> I noticed this with 2.6.25-rc2 (if not before), and the problem
> is still there with 2.6.25-rc6-git (as of this AM).
> 
> System is an Athlon64 single CPU laptop, and instead of reading a
> few dozen wakeups per second, it says a many tens of thousands...
> clearly wrong.  In previous kernels it gave more plausible counts;
> unfortunately high because of various un-evolved desktop tools in
> this Ubuntu system (Feisty).
> 
> Possibly more truthful, it says that the system never enters
> C1 or C2, and spends all its time in C0.  Though if I look at
> /sys/devices/system/cpu/cpu0/cpuidle/state[01]/usage, that
> seems to tell a different story ... it's C0 that's never used.
> In previous kernels it reported time in both C0 and C2.  ISTR
> some patch to avoid C2, which would explain part of this.
> 
> Comments or fixes, anyone?

This is likely to be an acpi regression, isn't it?

A git-bisect would be nice, please.