[Xenomai] OMAP L138

Gilles Chanteperdrix gilles.chanteperdrix at xenomai.org
Wed Apr 9 02:18:10 CEST 2014


On 04/09/2014 01:30 AM, Peter Howard wrote:
> On Tue, 2014-04-08 at 11:18 +0200, Gilles Chanteperdrix wrote:
>> On 04/07/2014 07:34 AM, Peter Howard wrote:
>>>
>>> On Wed, 2014-04-02 at 09:24 +0200, Gilles Chanteperdrix wrote:
>>>> On 04/02/2014 04:59 AM, Peter Howard wrote:
>>>>> Hi,
>>>>>
>>>>> I'm interested in running xenomai on a TI-OMAP L138 board.  I found the
>>>>> following thread in the archives:
>>>>>
>>>>> http://www.xenomai.org/pipermail/xenomai/2010-January/018898.html
>>>>>
>>>>> where someone was working on porting ipipe and xenomai to that board.
>>>>> However, the thread ended with problems still unresolved, and the patch
>>>>> in the thread (just the changes for ipipe) isn't in the ipipe
>>>>> repository.
>>>>>
>>>>> Does anyone know if this work was completed or just faded into the
>>>>> ether?
>>>>
>>>> We never merged a patch for this processor. And a lot of things changed
>>>> since that time. If you are interested in porting the I-pipe patch to
>>>> this processor, see:
>>>>
>>>> http://www.xenomai.org/index.php/I-pipe-core:ArmPorting
>>>>
>>>
>>> Contrary to what I said last week, I'm working on a patch off the head
>>> of the ipipe repo.  I have built a kernel with an ipipe port and with
>>> xenomai patched in.  However the latency results are bad right now:
>>>
>>> root at arago:~# xeno latency -T 25
>>> == Sampling period: 1000 us
>>> == Test mode: periodic user-mode task
>>> == All results in microseconds
>>> warming up...
>>> RTT|  00:00:01  (periodic user-mode task, 1000 us period, priority 99)
>>> RTH|----lat min|----lat avg|----lat max|-overrun|---msw|---lat best|--lat worst
>>> RTD|      3.541|      8.833|     60.749|       0|     0|      3.541|     60.749
>>> RTD|      3.499|     13.583|     93.916|       0|     0|      3.499|     93.916
>>> RTD|      3.666|     88.999|    109.708|       0|     0|      3.499|    109.708
>>> RTD|      3.541|     14.958|     95.374|       0|     0|      3.499|    109.708
>>> RTD|      3.541|      9.333|     77.583|       0|     0|      3.499|    109.708
>>> RTD|      4.041|     88.416|    109.791|       0|     0|      3.499|    109.791
>>> RTD|      3.499|      8.958|     72.791|       0|     0|      3.499|    109.791
>>> RTD|      3.499|     26.041|    106.874|       0|     0|      3.499|    109.791
>>> RTD|      3.874|     82.708|    107.916|       0|     0|      3.499|    109.791
>>> RTD|      3.499|      9.083|     73.708|       0|     0|      3.499|    109.791
>>> RTD|      3.333|      8.874|     62.458|       0|     0|      3.333|    109.791
>>> RTD|      3.333|      8.749|     62.208|       0|     0|      3.333|    109.791 
>>> RTD|      3.416|     12.708|     99.416|       0|     0|      3.333|    109.791 
>>> RTD|      3.499|     14.249|    106.749|       0|     0|      3.333|    109.791 
>>> RTD|      3.541|      9.083|     76.499|       0|     0|      3.333|    109.791 
>>> RTD|      3.249|      8.791|     63.499|       0|     0|      3.249|    109.791 
>>> RTD|      3.416|      8.999|     62.499|       0|     0|      3.249|    109.791 
>>> RTD|      3.541|     26.166|    101.208|       0|     0|      3.249|    109.791 
>>> RTD|      3.583|     13.624|     92.458|       0|     0|      3.249|    109.791 
>>> RTD|      3.541|      8.916|     73.708|       0|     0|      3.249|    109.791 
>>> RTD|      3.541|      8.999|     64.291|       0|     0|      3.249|    109.791 
>>> RTT|  00:00:22  (periodic user-mode task, 1000 us period, priority 99)          
>>> RTH|----lat min|----lat avg|----lat max|-overrun|---msw|---lat best|--lat worst 
>>> RTD|      3.499|      8.874|     61.374|       0|     0|      3.249|    109.791 
>>> RTD|      3.499|     13.833|    100.749|       0|     0|      3.249|    109.791 
>>> RTD|      3.541|     13.083|     99.249|       0|     0|      3.249|    109.791 
>>> ---|-----------|-----------|-----------|--------|------|------------------------
>>> RTS|      3.249|     21.458|    109.791|       0|     0|    00:00:25/00:00:25   
>>> root at arago:~# 
>>
>> Note that if the OMAPL138 is an armv4 or armv5, you may want to enable
>> the FCSE in order to reduce context switch time (and latencies).
>>
>>
> 
> I enabled FCSE, and the max latency is more consistent (though the min
> and average  latency has climbed).  How do the below figures look?

Without any load? It is meaningless.

-- 
                                                                Gilles.




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