Messages in this thread | | | Date | Fri, 18 May 2007 17:45:32 +0400 | From | Sergei Shtylyov <> | Subject | Re: [PATCH 2.6.21-rt2] PowerPC: decrementer clockevent driver |
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Hello.
Matt Sealey wrote:
>>>>>I haven't looked at all the new clock/timer code, is there any >>>>>utility in having support for more than one clock source?
>>>> Of course, you may register as many as you like.
>>>Sure, but is there any utility in registering more than the decrementer >>>on PPC?
>> Not yet. I'm not sure I know any other PPC CPU facility fitting for >>clockevents. In theory, FIT could be used -- but its period is measured in >>powers of 2, IIRC.
> Wouldn't it be possible to use SoC timer functionality, too, and not limit > this to what is only present on the CPU die?
If you have some SoC timers, you're welcome to add support for it. :-)
> I guess the real question is, how high resolution does a high resolution > timer need to be,
In the order of microseconds.
> and how often do you want to be handling interrupts?
That depends on a kind of functionality you need: HRT and/or dynamic tick...
> The 52XX has 8 general purpose timers and 2 slice timers. Both will > generate an interrupt once the clock hits a preset value, the timing > of which is determined by prescalers and the IPB clock..
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