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Re: [ts-7000] Re: high resolution timers and real time

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Subject: Re: [ts-7000] Re: high resolution timers and real time
From: Peter Gammie <>
Date: Mon, 18 Jan 2010 17:14:51 +1100
Charles:

On 18/01/2010, at 4:20 PM, Charles wrote:

> Any chance you could pass the clockevents patch on to Matthieu to include in 
> his patchset? HRT would help lots of users, I think, even without the -rt 
> support.

No promises, but I could try to do that if anyone else shows an interest. :-)

Are Matthieu's patches hosted anywhere except in the Yahoo file area? Can he 
(or someone) tell me what the status wrt the linux mainline is? I'm not a 
kernel hacker, but I surmise that RT got merged sometime around 2.6.31, and 
there seem to be have been a steady stream of ts72xx/ep93xx patches going in.

The 2.6.29.6 kernel I built does sub-10ms delays, dare I say even sub-100ns 
delays using clock_nanosleep, but the RT scheduler (FIFO/highest priority) is 
not keeping up its part of the bargain: running top glitches the multiplexed 
display scanning loop. This loop is only twiddling some GPIO lines in the 
manner of Jim Jackson's ts_arm_util (i.e. reading and writing to the mmap'd 
GPIO addresses) - I can't make it much tighter. The CPU load due to my program 
is something like 0.01% all up.

I'll try to look into it sometime soon.

cheers
peter

-- 
http://peteg.org/



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