Performance Issue on Ubuntu Linux


We have deployed SU for Schools on Ubuntu Linux 14.04 using the Linux Terminal Server (LTSP) Edubuntu package. SU is accessed using Google Chrome.

We experience performance issues in the form of intermittent “freezing” where the interface becomes unresponsive for short periods (then processes all the accumulated mouse clicks) and jerky rendering, particularly when orbiting models.

Initially Google was configured to run the on the server (HP high-end server 16-core CPU, lots of RAM, Disk etc). Monitoring of both the server and Internet showed little impact with up to 15 students working concurrently (server cpu topped out at max 30%, no swapping, Internet usage minimal).

Next we tried re-configuring to have Google Chrome run on the client computers so WebGL could take advantage of the local GPU. Standard desktop is a Dell Optiplex with dual-core CPU, 2Gb RAM and Radeon HD2400 Pro GPU. Monitoring again showed little CPU impact (intermittently topped out at 70% for very brief moments, no swapping and again no impact on Internet).

Freezing and jerkiness continued with a general observation that performance on the desktops was slightly less then the server (possibly because of combined server CPU grunt).

The models being worked by the students are fairly simple design for a small wooden serving tray with handles, so not a lot of elements.

System monitoring seems to show that the hardware is not bounding anything, but we are not sure what other resources SU and/or WebGL needs to run well.

We are looking on advice/experiences/guidance from the community on what we can do to improve the performance.

Best regards,

Andrew Foote for Newcastle Waldorf School

SketchUp uses WebGL (and OpenGL in desktop version), so on a terminal server without GPU this probably causes the browser to fallback to (unaccelerated) software rendering. The web version of SketchUp (a variant of the desktop version ) is first downloaded into the browser and executed locally with afterwards little to no network requests.

If it is also jerky on the client computers I suspect either a graphics driver problem or that Chrome does still use software rendering like on the server.

  • Does the window manager interfere and cause lags (are you using Unity7 or another desktop, low graphics mode or normal)?
  • Did you check that it actually uses WebGL? Chrome sometimes disables WebGL even if it is working (check out the chrome:flags for force-enabling it). The latest version (SketchUp Free) requires WebGL2 and does not always fallback to WebGL, I don’t know if this applies also to SketchUp for Schools.

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