Messages in this thread | | | Date | Fri, 18 May 2007 18:52:42 +0400 | From | Sergei Shtylyov <> | Subject | Re: [PATCH 2.6.21-rt2] PowerPC: decrementer clockevent driver |
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Hello.
Albert Cahalan 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.
> I'd really like to have that as an option. It would allow oprofile > to safely use hardware events on the MPC74xx "G4" processors. > Alternately it would allow thermal events. It is safe to use at > most one of the three (decrementer,profiling,thermal) interrupts. > If two were to hit at the same time, badness happens.
Unfortunately, FIT exists only on Book E CPUs and MPC74xx aren't Book E, IIUC.
> It's possible to wrapper the interrupt in something that divides > down, calling the normal code only some of the time. I think one > of the FIT choices is about 4 kHz on my system, which would be OK.
Erm, are you sure you have FIT (or is your system not MPC74xx based)?
> Full oprofile functionality would be wonderful.
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