Messages in this thread | | | Date | Fri, 25 Mar 2011 03:13:04 -0400 (EDT) | From | Len Brown <> | Subject | Re: [RFC PATCH V4 2/5] cpuidle: list based cpuidle driver registration and selection |
| |
> > So what do you suggest can be removed? > > Can we use safe_halt() until intel_idle/acpi_idle take over? But what > if they do not take over? If safe_halt() is not very bad compared to > the variants like mwait_idle and c1e_idle, then we can remove the old > code and no need to move them to default driver.
One reason I'd like a default cpuidle driver is that today there is a race. cpuidle registers, but until its driver registers it will use polling. go ahead and look:
grep . /sys/devices/system/cpu/cpu*/cpuidle/state0/usage
that should be 0, but it isn't...
> > >Are we suggesting that x86 must always build with cpuidle? > > >I'm sure that somebody someplace will object to that. > > > > Arjan argued that since almost everyone today runs cpuidle > > it may be best to include it in the kernel > > (https://lkml.org/lkml/2010/10/20/243). But yes, we agreed > > that we would have to make cpuidle lighter incrementally. > > Making ladder governor optional could be one way for example. > > > > > >OTOH, if cpuidle is included, I'd like to see the > > >non-cpuidle code excluded, since nobody will run it... > > The non-cpuidle code will be the select_idle_routine() and related > function that cam move to default_driver that register to cpuidle. > We can load on-demand as module if better routines fail to register. > Maybe we don't need this at all as discussed in the above point?
Right, though I don't share your fascination with modules.
cheers, Len Brown, Intel Open Source Technology Center
| |