Keeping the Screen Turned off While Getting Inputs

[Vladimir Dergachev]

On Sat, 26 Aug 2023, Ahmad Nouralizadeh wrote:

> >> Those accesses might not stop with just the display off - some
> >> applications may keep redrawing.
> Will these accesses cause iGPU or dedicated GPU accesses to the DRAM? I think that those redrawings originate from the processor.
> 
> >I'm not sure a graphical benchmark will run without a graphical system
> >running?
> Yes, VLC is one of the benchmarks and will not run without GUI.

You can start system with plain X and twm for window manager - this would 
produce minimal load on the GPU.

However, I would have expected that VLC would produce a lot GPU/iGPU 
accesses even without drawing anything, because it would try to use GPU 
decoder.

Displaying video is also often done using GL or Xvideo - plain X is too 
slow for this.

> 
> >Maybe do the reverse of what I suggested. Run the benchmark but send
> >the output to a remote display.
> Will it avoid screen activation in the local machine?

There should be a rather drastic difference in speed between VLC 
displaying locally and in a remote X using network.

best

Vladimir Dergachev

> 
> >Since IMC counters appear to be a feature of the powerpc architecture,
> >you might get a better response from some list/forum specific to that
> >architecture.
> 
> IMC stands for the Integrated Memory Controller. The DRAM controller has some internal counters for counting different types of memory accesses. For example, for my laptop it is documented here:
> https://software.intel.com/content/www/us/en/develop/articles/monitoring-integrated-memory-controller-requests-in-the-2nd-3rd-and-4th-generation-intel.html
> 
> Do you have any suggestions about the cause of the xrandr error? It works perfectly in the virtual machine!
> 
> 
>