Re: [Xenomai] Altera Cyclone V

[Charles Steinkuehler <charles@steinkuehler.net>]

On 1/7/2014 5:13 PM, Gilles Chanteperdrix wrote:
> On 01/07/2014 11:55 PM, Charles Steinkuehler wrote:
>> On 1/7/2014 4:47 PM, Gilles Chanteperdrix wrote:
>>> On 01/07/2014 11:19 PM, Charles Steinkuehler wrote:
>>>> The single-core A8 on the BeagleBone is good for about 25 uS
>>>> typical and 80 uS or so worst case latency.
>>>
>>> That is really high. On a 720MHz OMAP3, with the latency test
>>> running with a 100us period, I typically get latencies close to
>>> 40us (under dohell load). Granted I do not run many
>>> functionalities of the SOC (typically, not the graphic
>>> processor), but I would not expect latencies to get so high. Is
>>> there any chance you could trigger a trace with the I-pipe
>>> tracer?
> 
>> I can try...give me a while to sort through the I-pipe:Tracer wiki
>> page (or are there better instructions?).
> 
> Enable I-pipe tracer in kernel configuration, especially
> IPIPE_TRACE_MCOUNT, and IPIPE_TRACE_VMALLOC.
> 
> When the system has booted, do:

<snip>

Thanks for the details!  My to-do list just got longer...  :)

I'll do some testing (on the BeagleBone) and post the results, but it
might take a couple of days.

FYI, the GPU is currently disabled on the BeagleBone, so no mysterious
latency from that source (hopefully).  I need to migrate to a 3.12
kernel to get the GPU working (and it doesn't currently support X11,
only framebuffer applications), which is part of why I'm interested in
Xenomai on the 3.10 or newer kernel for the Cyclone-V SoC.

-- 
Charles Steinkuehler
charles@steinkuehler.net

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