Re: can4linux compilation for i.mx25 under 2.6.39

[Marc Kleine-Budde <mkl@pengutronix.de>]

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On 05/30/2012 02:50 PM, Martin Kozusky wrote:
>>> The best for me would be some kernel module which would just put the CAN
>>> frame into some big "from userspace available" buffer in the interrupt
>>> and nothing more. My app would check if there is anything new and read
>>> it out.
>>> There are around 1500/sec (at 250kbit) can frames on the bus when the
>>> problem arise, I think it's not that much.
>>
>> Are you writing the can frames to storage in the same thread as
>> receiving them?
> 
> 
> No, CAN has it's own thread, which is just making struct from can
> messages (reading via select() )  and writes them into another buffer.
> Then the main thread reads this buffer and writes to SD card. Now I
> changed it so that this buffer is 30MB big, so I first store all the
> messages into RAM, and when I don't need to record CAN frames anymore, I
> write all of them to card from this big buffer.
> But this is just limited workaround because I'm limited with the RAM
> size (so I had to make the buffer cyclic and just latest xxxx messages
> are stored, older are overwritten when the buffer is full).

Have you setup realtime priorities for you CAN thread?

Marc


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