process wakeups

Tue Jul 15 15:57:27 UTC 2008

On Tue, Jul 15, 2008 at 11:52:35AM -0400, Dan Williams wrote:
> On Mon, 2008-07-14 at 14:57 -0700, Ulrich Drepper wrote:
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> > 
> > One of the worst problems wrt energy savings we have today are all the
> > wakeups processes request.  This is not just an issue for laptops, it
> > relevant everywhere.
> > 
> > To see the size of the problem run the attached systemtap script.  On my
> > laptop I see the following output (47 secs runtime):
> > 
> >   uid | poll select  epoll itimer  futex nanosle signal| process
> > 29799 |15941   7971      0      0      0       0      0| npviewer.bin
> > 29841 |  253      0      0      0   1531       0      0| thunderbird-bin
> >  3017 |  447      0      0      0      0       0      0| pulseaudio
> >  2467 |   76      0      0      0      0       0      0| hald
> >  2471 |    8      0      0      0      0       0      0| hald-runner
> >  2620 |   58      0      0      0      0       0      0| NetworkManager
> 
> While there are probably stupidities in NM, there are also known
> externally-driven wakeup causes including:
> 
> 1) until 2.6.27 lands, there's no way to get the rfkill switch
> state-change events, so NM polls them every 6 seconds _iff_ they exist.
> Unfortunately, they often exist in HAL even though there are no physical
> switches on the laptop because the nice rfkill patches haven't landed
> yet (again, scheduled for 2.6.27)

Ahhh, so that's probably what's causing /usr/libexec/hal-ipw-killswitch-linux
to be run every 6 seconds, which in turns causes any app connected to DBus
system bus to be send a signal every 6 seconds and thus causes all the
hits against libvirtd - and a fair number of other apps in that list too

Daniel
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