[Xenomai] NVIDIA Drivers w/ Xenomai

Jeff Webb jeff.webb at nta-inc.net
Tue Dec 22 18:33:57 CET 2015

On 12/22/2015 09:54 AM, Lennart Sorensen wrote:
> On Tue, Dec 22, 2015 at 08:30:37AM +0100, Gilles Chanteperdrix wrote:
>> Last time I looked, NVIDIA drivers used some glue code to adapt to
>> the particular kernel for which they were compiled. This glue made
>> use of the standard macro local_irq_save/spin_lock_irqsave, etc...
>> So, compiling the NVIDIA driver with an I-pipe kernel worked, and so
>> did running Xenomai programs along side graphic applications. But
>> that was a long time ago. In any case, running the latency test
>> while your image processing program is running on the GPU should
>> allow you to find whether the driver is generating large latencies.
> OK, maybe it isn't as bad as I was led to believe in the past then.
> I suppose one could hope there are no interrupt disable calls in the
> nvidia binary blob directly.

I have experienced some high worst-case latencies when using the NVIDIA drivers along side Xenomai real-time code in the past.  The open source drivers seemed to be more well-behaved from a real-time point of view.  You may be able to get the closed-source drivers to work for your application, depending on your timing constraints and GPU feature usage.  As Gilles mentioned, you really should try running the latency test while putting the system (and GPU) under load.  As I remember, switching to another virtual console sometimes triggered some nasty behavior.


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