Re: [Xenomai-help] test result on at91rm9200

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

robert165 wrote:
> 
> 
> 
> 在2009-12-28，"Gilles Chanteperdrix" <gilles.chanteperdrix@domain.hid> 写道：
>>robert165 wrote:
>>> Hi,
>>> I have tested xenomai on my at91rm9200 board, I used
>>> xenomai 2.4.10 + linux-2.6.28 + adeos-ipipe-2.6.28-arm-1.12-05.patch
>>> Test result seems very poor, is that correct?
>>
>>Your test results are rather good for an at91rm9200 board, which is the
>>sure sign that you are not loading the system enough.
>>
>>As I already told, you, the expected results are:
>>- user-space latency of 260us without FCSE
>>- user-space latency of 200us with FCSE
>>- kernel-space latency of 50us if running with unlocked context switches
>>(an option which is only available in the upcoming 2.5 branch).
>>
>>> And is there any introduction of the tests, as their purper, their
>>> meanling...
>>
>>The latency test computes some latencies (either user-space scheduling
>>latency, kernel-space scheduling latency, or kernel-space interrupt
>>latency, depending on the options). The switchtest tests context
>>switches. The switchbench measures context switching time. cyclictest
>>does the same thing as the latency test (only, you need to run it with
>>the right options to avoid running in fact with Linux timer), and in
>>general return similar results. Here I do not know what is the meaning
>>of cyclictest results you got, but if you want to know, I am afraid you
>>wil have to investigate, or simply ignore them.
>>
> 
> Thanks for your introdution, and is there any document of it. 
> The man pages just explain  parametres  of test scripts.  I could
> not understand the output of some test.

No there is no document. But patches are welcome, as usual. As far as I
can tell, I explained you what the tests do, there is not much more to
tell. Which test's output did you not understand?

> 
>>> 
>>> Test is under loads as followed,
>>>     dd if=/dev/zero of=/dev/null > /dev/null &
>>>     ping 172.18.23.10 > /dev/null &
>>>     while ls; do ls; done > /dev/null &
>>
>>This load is laughable. Do you find that they really stress the system,
>>that they make it really unresponsive? Do you really expect a test which
>>sends one packet every second over network to stress the system in some
>>way? That is what I meant when I said hammering the system real hard.
> 
> The reason I procuce the load is: 
> https://mail.gna.org/public/xenomai-help/2008-01/msg00023.html
> How can I produce a real hard load. Are there any direction about it.

The mail you are refering to is using ping -f, not ping, and talks about
stressing cache by running the cache calibrator. The way we do our tests
evolved a bit since then. We use netcat instead of ping -f, and the
hackbench test to stress the linux scheduler. That is when FCSE is
enabled in guaranteed mode. Without FCSE, we use ltp (the linux testing
project) and netcat.

-- 
					    Gilles.