Michel Rinaldi wrote:
> ----- Messaggio originale -----
> Da: "Gilles Chanteperdrix" <[email protected]>
> A: "Michel Rinaldi" <[email protected]>
> Cc: [email protected]
> Inviato: Lunedì, 24 gennaio 2011 17:54:51 GMT +01:00
> Amsterdam/Berlino/Berna/Roma/Stoccolma/Vienna
> Oggetto: Re: [Xenomai-help] Problems with rt_task_create and rt_task_join
>
>
>> Ok. Sorry, the rt_sem_p is actually waiting for the semaphore. So, for
>> it to take a long time, the kernel module would have to post it all the
>> time. In the kernel module, you should check rtdm_task_wait_period
>> return value.
>>
>> Anyway, what I said still stands: if we suspect the application of being
>> the culprit, we should try and run a system without this application
>> first. That is, only latency and some non real-time load.
>
> I run a latency test for about 2 hours, in concomitance with two
> dd if=/dev/zero of=/dev/null
> commands and some sporadic ssh big file transfers. Last row in test output
> was:
>
> RTD| 6.546| 7.191| 10.346| 0| 0| 1.101| 29.508
>
> Maximum latencies was obtained during file transfers.
> With this result I think that I could assert that Xenomai works properly on
> my system, is right?
Well, no. dd if=/dev/zero of=/dev/null is far from being a proper load.
What you should do is at least to create some disk and network activity,
continuously. And the ideal, is to run the LTP test in parallel. If you
can not, then at least run hackbench in a loop. All this during several
hours.
>
> In facts, same test (only without file transfer) under another system with
> 1GHz Intel Atom on a SCH (Poulsbo) chipset (not supported by Xenomai to
> disable SMIs) reports these results:
>
> RTD| 11.353| 13.808| 31.264| 3| 0| 2.934| 231.539
>
> I think high latencies are due to SMIs.
> By the way, is there a reason why Xenomai does not disable SMIs on SCH
> chipsets?
We add ids to the smi.c table when people send patches, and report that
the workaround... works. Anyway, if you suspect that the ICH workaround
does not work with SCH chipsets, you should have a look at the SCH
chipsets datasheet, to check whether the method for disabling SMIs is
the same.
What I do not understand, in on which system you get the issue with your
test application. If you want to know if the system on which you run the
test has an isssue, then surely you should test this system, not another...
--
Gilles.
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