2008-06-18 21:49:45 Realtime operations?

Steve M (UNITED STATES)

Message: 57544

Hello

I've got a userland program that samples data from an I/O register. The data changes very quickly (500k times per sec). I am only grabbing the data for two seconds, but during this time, it is imperative that my process not be interrupted. With the stock uclinux configuration, I am noticing gaps in the data stream from the process being interrupted by the scheduler.

Is there a way to prevent the process from being interrupted for a brief period?

How might I be able to achieve this in the shortest time possible? Is there some sort of system function I can call to disable further interrupts and scheduling until a certain point in the program?

Thank you

Steve

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2008-06-18 22:06:26 Re: Realtime operations?

Mike Frysinger (UNITED STATES)

Message: 57545

you may be able to mitigate it, but there is no way to absolutely prevent it

linux is not hard real time ... it is soft real time. if you need hard real time, then you need to use a hard real time OS. perhaps xenomai can help:

http://docs.blackfin.uclinux.org/doku.php?id=linux-kernel:adeos