[Xenomai] Negative latencies

[Xenomai] Negative latencies

[John Sini]

Hello,


I was trying to boot linux with Xenomai on the Zedboard from Xilinx. When I
run the latency test I get negative values. I tried to calibrate my system
by running the following
echo 1 > /proc/xenomai/latency


But then when I run

cat latency - I get 0. I also get 0 if I put 2 or 3ns. If I put 4 i.e.

echo 4 > /proc/xenomai/latency and then do:

cat latency - I get 3.

Is there a possibility to calibrate my system to 1ns? Can the calibration
be done without echo 1 > /proc/xenomai/latency somehow in latency.c. Before
doing any calibration latency that I get is 9498.

Thanks,
John

Re: [Xenomai] Negative latencies

[Gilles Chanteperdrix]

On Tue, Jan 13, 2015 at 06:01:54PM +0100, John Sini wrote:
> Hello,
> 
> 
> I was trying to boot linux with Xenomai on the Zedboard from Xilinx. When I
> run the latency test I get negative values. I tried to calibrate my system
> by running the following
> echo 1 > /proc/xenomai/latency
> 
> 
> But then when I run
> 
> cat latency - I get 0. I also get 0 if I put 2 or 3ns. If I put 4 i.e.
> 
> echo 4 > /proc/xenomai/latency and then do:
> 
> cat latency - I get 3.
> 
> Is there a possibility to calibrate my system to 1ns? Can the calibration
> be done without echo 1 > /proc/xenomai/latency somehow in latency.c. Before
> doing any calibration latency that I get is 9498.

See:
https://xenomai.org/pipermail/xenomai/2007-May/009063.html

-- 
					    Gilles.