On 05/18/2012 09:06 AM, Jean-Pascal JULIEN wrote:
>>> Hi,
>>>
>>> I installed xenomai on an overo water board (cortex A8) and performed
>>> latency tests.
>
>> What version of Xenomai?
>
>>> I tested two modules.
>>> The first module is based on an internal timer. It toggles a GPIO each
>>> 1ms.
>>> The second module waits for an external interrupt from an input GPIO
>>> (square signal at 1KHz). When that happens, the module toggles a GPIO pin.
>>>
>>> When i load the system and do a transfer from Ethernet to the sd card the
>>> first module works fine with a maximum latency less than 50us.
>>> But the second module, in the same context, have a maximum latency of
>>> several milliseconds.
>>>
>>> As the first module works fine i think i have a problem with the hardware
>>> configuration like the hardware irq priority.
>>> In the irq.c file, the irq priority level is not set for the linux domain.
>>>
>>> Should i configure the irq level at the initialization of the board ? What
>>> else could cause this issue ?
>
>> The error is more likely in the code of your driver. Show us the code.
>
> Hi Gilles,
>
>
> Sorry, i forgot the essential.
> My linux kernel version is the 2.6.38 from sakoman.
> My xenomai version is xenomai-2.6.0
> The adeos patch is : adeos-ipipe-2.6.38.8-arm-1.18-04.patch (
> ./prepare-kernel.sh --linux=${WORKDIR}/git --arch=arm
> --adeos=${WORKDIR}/xenomai-2.6.0/ksrc/arch/arm/patches/adeos-ipipe-2.6.38.8-arm-1.18-04.patch).
> The xenomai user space is make with the next configuration :
> ./configure --build=arm-ti-linux --host=arm-none-linux-gnueabi --prefix=/usr
> --includedir=/usr/include/xenomai --enable-arm-tsc=omap3 --disable-dox-doc
> --disable-dbx LDFLAGS="-Wl,-O1 -Wl,--hash-style=gnu"
You do not need --enable-arm-tsc.
I see nothing wrong with your code. However this version of the I-pipe
patch has a bug with gpio irqs. You can try backporting this patch:
http://git.xenomai.org/?p=ipipe-gch.git;a=commit;h=81bfc05c4716b76e79f5e486baf4c52015a3b92c
To fix it. If that is the cause of your problem, then you should only
see the bug if you are running some other real-time program which
triggers a user-space task wakeup based in an interrupt, such as for
instance the timer interrupt. Running the "latency" test for instance
would do that.
--
Gilles.
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