[Xenomai] OMAP L138

Gilles Chanteperdrix gilles.chanteperdrix at xenomai.org
Wed Apr 9 13:54:37 CEST 2014


On 04/09/2014 06:27 AM, Peter Howard wrote:
> On Wed, 2014-04-09 at 10:34 +1000, Peter Howard wrote:
>> On Wed, 2014-04-09 at 02:20 +0200, Gilles Chanteperdrix wrote:
>>> 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?
>>>
>>> Otherwise, it is hard to say whether there is an issue or not. It is not
>>> uncommon for armv4 or armv5 to have high latencies like this.
>>> On what core is this processor based, running at what frequency?
>>>
>>>
>> It's an AMR926EJ-S r5.  Datasheet claims 375MHz, U-boot claims 300MHz.
>>
>> Load test to follow.
>>
> 
> OK, this run was done with LTP running on the board (runltplite.sh),
> with cpu utilization between 90% and 100%

You have to run the latency test while ltp is running, and run this for 
a few hours (ltp runs a few hours anyway).

We provide the xeno-test script to do this (and dohell to generate 
load).

See:
http://www.xenomai.org/documentation/xenomai-2.6/html/xeno-test/index.html
http://www.xenomai.org/documentation/xenomai-2.6/html/dohell/index.html

-- 
                                                                Gilles.




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