Re: rtlinux dma get_buffer_contents number of bytes transferred

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On Tuesday 23 March 2004 05:42 am, Vitor Angelo wrote:
>
> An additional information is that I've tested with PCIDMA disabled and
> enabled in comedi/drivers/ni_pcimio.c. It's not possible to use with DMA
> because latencies are too big and the "long sleep" problem happens just
> a few minutes after the program starts.

Would you clarify what you mean by the latencies being too big with dma 
enabled?

>
> I've also performed a lot of "torture" tests (with disk and network IO)
> and the callback latency always remained below 30us (20us in a idle
> system). The 1ms glitches always happened after one hour running the
> program with the system idle.
>
That sounds pretty suspicious.  Does your computer have a bios setting to 
put the machine into low-power mode after an hour idle?

- -- 
Frank

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Received on 2004-03-24Z00:50:29