V-REP on Ubuntu runs 2x slower than on Mac or Windows

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symlee18
Posts: 2
Joined: 30 Nov 2018, 18:09

V-REP on Ubuntu runs 2x slower than on Mac or Windows

Post by symlee18 » 07 Dec 2018, 15:02

Hi, I'm observing that identical code runs with a real-time factor of 0.90 on a Mac Sierra and 0.41 on Ubuntu 16.04. I expected similar simulation speeds as both are high performance computers (Mac Pro with i5 4 cores 3.1 Ghz, and Dell with i7 8 cores 2.8 GHz). Would you know why this may be happening and how to increase the simulation speed on Ubuntu?

I've included links to relevant V-REP screenshots below and can also provide a link to the code if it would be helpful.

V-REP on Mac: https://www.pastepic.xyz/image/0fWrr
V-REP on Ubuntu: https://www.pastepic.xyz/image/0ftlw

I observed a real-time factor of around 0.90 on a Microsoft Surface Pro 4, i7 2017 as well.

coppelia
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Posts: 6867
Joined: 14 Dec 2012, 00:25

Re: V-REP on Ubuntu runs 2x slower than on Mac or Windows

Post by coppelia » 10 Dec 2018, 14:56

Hello,

I suspect that rendering is the culprit. You can see the rendering time in the Window bar.

Cheers

symlee18
Posts: 2
Joined: 30 Nov 2018, 18:09

Re: V-REP on Ubuntu runs 2x slower than on Mac or Windows

Post by symlee18 » 11 Dec 2018, 03:38

I think you're right. When I use the embedded video recorder in V-REP, the simulation is recorded in real-time (which is much faster than the simulation time which is slowed down by rendering).

I've tried following the suggestions found here viewtopic.php?t=19 and turned off vsync (by editing /etc/X11/xorg.conf on Ubuntu) and experimented with the useGlFinish, vsync, and debugOpenGl parameters in V-REP's usrset.txt. I've also tried to tuning my Intel graphics card by editing /etc/X11/xorg.conf to match the configuration suggested here: https://www.techzim.co.zw/2017/06/tunin ... ntu-16-04/.

Unfortunately, the slow rendering persists. a) Is there anything else that I can do to try and speed up the rendering?

And I've also tried running the simulation in headless mode on Ubuntu but it only seems to provide around a 15% reduction in simulation time, which is lower than I expected. b) Is there anything that you suggest I do to increase the simulation speed in headless mode apart from the suggestions posted here: viewtopic.php?f=9&t=2247?

coppelia
Site Admin
Posts: 6867
Joined: 14 Dec 2012, 00:25

Re: V-REP on Ubuntu runs 2x slower than on Mac or Windows

Post by coppelia » 12 Dec 2018, 11:00

Did you try to install a better driver for your graphic card?
The headless mode you are talking about is still generating vision sensor images, thus the small speed gain you see (you have 4 vision sensors in your scene from your screenshots). You could also try to play with the OpenGl settings such as offscreen context type, FBO type and/or VBO operation.

Cheers

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