CLUSTER: FRAMEBUFFER AND VIDEO OUTPUT USING LXSESSION

[claudio4parallella]

Hi,
I'm going to some slow progress on my needs.

MY SCENARIO
- Cluster of 4 parallellas, 64 core, via eLink; 3 SLAVE parallellas, 1 MASTER parallella
- Mandatory usage of old img ubuntu-14.04-headless-z7010-20150130.1.img , the only capable of make working eLink Custer
- The Cluster application produce a PNG file
- Installing lxde, ok graphic desktop with VNC, may be useful for GTK graphic applications

MY MISSING
- No existing Framebuffer /dev/fb0 using ubuntu-14.04-headless-z7010-20150130.1.img
- No existing Video Output, no HDMI using ubuntu-14.04-headless-z7010-20150130.1.img
- No possibility to use the last IMG with HDMI / Framebuffer with the Cluster

MY NEEDS
- I need to output the bitmap produces by the fast 64 cores cluster immediately to a video, using for example the Framebuffer and "lxsession" or "framebuffer-vncserver": using a Raspberry Pi I use to display bitmap on my MAC directly written into the Framebuffer /dev/fb0

MY WAYS
**BOOT** : I've put the HDMI BOOT files: devicetree.dtb and uImage I got at in place of the ubuntu-14.04-headless-z7010-20150130.1.img original headless boot files.
**RESULTS**: 1) The Framebuffer /dev/fb0 is generated; framebuffer is working succesfully write into; 2) no way to run "lxsession" or "framebuffer-vncserver" and show my bitmap generated by the 64 cores cluster 3) Epiphany sdk is not working at all.
May be the uImage or bitsteream is not compatible with epiphany and esdk

MY CONCLUSIONS:
- even if I've succesfully setup the Framebuffer, I've not the results of video output of bitmap within the Headless system.

Any Further Suggestion?
Thanks in advance

[njpacoma]

I have not worked with this myself but it is possible to display graphic images using the X Window system.

Check out the code in https://github.com/esainty/parallel-mandelbrot -- this program uses native X11 to display the calculated graphic. It is relatively clear from the code how the X11 window is created and written to. It works even when I am connected to my system using VNC. It might even work with X11 forwarding via ssh.

If you want to run the program, you first have to install libx11-dev (and any dependencies). Then, since this is an MPI program, you have to compile it with: mpicc -o pm pm.c -lm -lX11 (I renamed the code file and I use MPICH--the Parallella has OpenMPI installed and although they seem to be nearly the same, I have not tried this using OpemMPI) and once you have it compiled you can run it like this: mpirun --np 4 ./pm -- be patient because the default calculation is complex and takes a while to complete (on my 16 core mpi stack it seems to take between 2 and 3 minutes).

If I recall correctly, there also is/was an xtemp application that would use ssh X11 forwarding to show a running temperature graph in a window--I can't find this right now but the X11 work has to be similar to the mandelbrot program.

Hope this provides a usable alternative.