Re: [PATCH] atmel_tc clocksource/clockevent code

[Thomas Gleixner]

On Wed, 5 Mar 2008, Remy Bohmer wrote:
> Hello David,
> 
> > Could you elaborate on where that 50-100 usec gets spent?
> 
> Attached I have put a screendump of my ETM debugger. It shows a
> complete flow of kernel function-calls of what happens on a timer
> interrupt. In this example the complete sequence takes about 154 us.
> Notice that the ETM is non-intrusive, and that the times are real and
> accurate in this trace. (you can even see the effects of CPU-caches,
> sometimes the same code just runs faster)

Is there any chance to convert this to a text table? Following that
png is pretty hard.

> So, hires timestamps -> really really welcome.
> hires timers -> there should be a (configurable) minimal resolution
> that fits the hardware to not overload the CPU.

clockevents let you set a minimum delta already. This can be set at
runtime before registering the device.

Thanks,

	tglx
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