Re: [Xenomai-help] RT OS Selection advice for parallel processing

[Jan Kiszka <jan.kiszka@domain.hid>]

On 2011-02-03 12:04, Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>> [ And, personally, I don't trust the NVIDIA driver a lot. But that might
>> be influenced by the fact that latest versions lock up my notebook
>> regularly after resume and that I filed another obvious locking issue of
>> the compilable driver stub around mmap_sem without any response from the
>> vendor. ]
> 
> Some colleague of mine is using the NVIDIA driver (through the opengl
> mapping, not CUDA/VDPAU, whatever) on high-end NVIDIA boards in a non RT
> situation. he definitely observed some huge latencies not due to
> scheduling issues, when uploading textures to the GPU. We are talking
> tens of milliseconds here.

Ugh, tens of milliseconds is heavy, more than I would expect from
wbinvd. OTOH, uploading textures may involve mapping the RAM that
contains them for the GPU. To exclude that as source, he could try
instrumenting CACHE_FLUSH() (in nv-linux.h).

Jan

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