New subject: Matlab graphics performance when running in x2go

2 Jun 2020


      I finally figured it out! Now I can run Matlab R2019b on Ubuntu 18.04 LTS with decent graphics performance over x2go, even with transparency using the Mesa llvmpipe software OpenGL driver.
Benchmark for a simple scene:
No transparency: ~40 ms per frame
With transparency: ~58 ms per frmae
So still some performance penalty for transparency, but much better.
HOWTO:
First install LLVM: sudo apt install llvm-dev
I downloaded mesa-20.1.0 (latest version right now) and configured it like this (in the unzipped source directory):
mkdir build
cd build
meson -D glx=gallium-xlib -D gallium-drivers=swrast -D platforms=x11 -D dri3=false -D dri-drivers="" -D vulkan-drivers="" -D buildtype=release -D optimization=3 -Dprefix=/usr/local/mesa-20.1.0/
Then I built and installed it as follows:
ninja
sudo ninja install
Then to make Matlab load the new driver, I needed to modify Matlab's lib search path:
cp $MATLAB_DIRECTORY/bin/.matlab7rc.sh ~
Edit the file ~/.matlab7rc.sh, find the glnxa* section and add /usr/local/mesa-20.1.0/lib/x86_64-linux-gnu to LDPATH_PREFIX
Add to your .profile: export MESA_GL_VERSION_OVERRIDE=3.0
Seems like anything will work for the version override except for 3.1, but I didn't debug this further.
— 
Johannes Töger
Associate Senior Lecturer
Cardiac MR Group
Department of Clinical Sciences Lund, Clinical Physiology
Lund University, Sweden
-----Original Message-----
From: Ulrich Sibiller <uli42@gmx.de>
Sent: Wednesday, May 27, 2020 14:29
To: Johannes Töger <johannes.toger@med.lu.se>
Subject: Re: [X2Go-User] Matlab graphics performance when running in x2go
Thanks!
On Wed, May 27, 2020 at 1:59 PM Johannes Töger <johannes.toger@med.lu.se> wrote:
...
OK I see - we only have CUDA cards in those machines to do computations, so VirtualGL won't work then.
Maybe I'll try to compile an optimized software Mesa/Gallium -- I'll let you know what happens if I find something interesting, so it's documented on the mailing list at least.
—
Johannes Töger
Associate Senior Lecturer
Cardiac MR Group
Department of Clinical Sciences Lund, Clinical Physiology Lund
University, Sweden
-----Original Message-----
From: Ulrich Sibiller <uli42@gmx.de>
Sent: Wednesday, May 27, 2020 13:20
To: Johannes Töger <johannes.toger@med.lu.se>
Cc: x2go users <x2go-user@lists.x2go.org>
Subject: Re: [X2Go-User] Matlab graphics performance when running in
x2go
On Wed, May 27, 2020 at 1:07 PM Johannes Töger <johannes.toger@med.lu.se> wrote:
...
Thanks for your quick reply.
It turns out that Matlab by default uses an older Mesa software rendering module (17.3) when there is no hardware OpenGL. I tried to compile my own version with additional optimizations and LLVMPipe etc, but Matlab wouldn't accept it. No more time to debug it today, but maybe later.
Is there any documentation on using VirtualGL with x2go? I tried to google it, but no luck.
Not that I am aware. I have never checked it out practically.
Generally you will have to dedicate the graphics hardware to that
(only) session which might make it a no-go, depending on your setup.
Uli