How to improve interactive performance of MATLAB#
When using ssh X11-Forwarding (options -X or -Y), matlab can
be slow to start and also exhibit slow response to interactive use. This
is because X11 sends many small packets over the network, often
awaiting a response before continuing. This interacts unfavorably with
medium or even higher latency connections, i.e. WiFi.
A way to eliminate this issue is to use dedicated resources and to
start a remote desktop session that does not suffer from network
latencies in the same manner. This approach requires a VNC client
vncviewer installed on your local machine. A widely used VNC
client is TurboVNC.
If your local machine has Linux or mac operating system you can use a
launcher
provided by DKRZ to easily establish a VNC connection to a Levante
node. The launcher automatically connects to Levante, reserves a node,
starts a vnc server and connects to this server using your local
vncviewer. You need to complete the downloaded script start-vnc by
adding your personal user and project accounts or to use the
corresponding command line options, for example:
your-machine:~> chmod u+x start-vnc
your-machine:~> ./start-vnc
your-machine:~> ./start-vnc -u <userid> -v /path/to/vncviewer -b '-A <project-id> -p interactive --mem=10G'
To list all available command line options execute:
your-machine:~> ./start-vnc -h
If you have not set a VNC server password yet, the vncpasswd
command will be called in the script and you will be prompted to
create a password:
No VNC password found. Please set now.
...
Password:
Verify:
Would you like to enter a view-only password (y/n)? n
The created password will be stored in the $HOME/.vnc/passwd
file. Since it only protects the VNC session, it should be different
from your regular access password to DKRZ services. Also, since the
password will only be used in automated logins afterwards and you
don’t need to enter it on the console, it can be long and random at no
cost. Furthermore, public key based login to Levante is recommended to
avoid multiple entering of your regular password.
In the VNC desktop that should appear on your local workstation, open a terminal window by clicking the Activities menu and typing terminal in the search field subsequently shown.
Thereafter, you can load the matlab module in the terminal window
and start the application:
$ source /etc/profile
$ module load matlab
$ matlab &
On GPU nodes, the program execution can additionally benefit from
hardware acceleration for 3D-plots or other graphics-intensive matlab
sessions. In this case you need to start matlab with vglrun and
without software OpenGL:
$ vglrun matlab
To terminate your VNC session choose the Disconnect icon [x] in the top menu of the VNC desktop.