Messages in this thread | | | Date | Fri, 13 Dec 2013 10:51:23 +0530 | From | Preeti U Murthy <> | Subject | Re: [RFC PATCH] time: Support in tick broadcast framework for archs without an external wakeup source |
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Hi Ben,
On 12/13/2013 10:47 AM, Benjamin Herrenschmidt wrote: > On Fri, 2013-12-13 at 09:49 +0530, Preeti U Murthy wrote: >> On some architectures, in certain CPU deep idle states the local timers stop. >> An external clock device is used to wakeup these CPUs. The kernel support for the >> wakeup of these CPUs is provided by the tick broadcast framework by using the >> external clock device as the wakeup source. > >> However on architectures like PowerPC there is no external clock device. > > Minor nit ... > > I wouldn't make this an architectural statement. Some PowerPC's do have > external clock devices (for example the old MPIC interrupt controller > had timers). In fact, if we really need it, I'm sure we *could* find > something somewhere in P8 that could act as a timer, probably hijacking > a bit of the OCC or similar but at this stage, that's not on the radar. > > So make it an implementation statement. "However, not all > implementations, such as some PowerPC ones, provide such an external > timer ...".
Thanks for this information. I will update this going ahead.
Regards Preeti U Murthy
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