Octane idles at 100% CPU on Linux

Sun Mar 13, 2011 5:57 am

Hi,

I didn't notice so far as Octane is always taking lot of CPU on Linux while rendering, but it appears it anyway takes steady 100% CPU shortly after loading, with no scene loaded.

Any clue?
Lionel

Sun Mar 13, 2011 7:57 am

That observation was the first thing I posted, when joining the club

Try to keep your mouse on a menu (just open the file menu, for example) - that will turn down the CPU usage to "0%", but when you close the menu, it will go back up to 100% = interesting and something worth to inspect.

Sun Mar 13, 2011 8:10 am

I've just tried this on windows7 and no such problem. Idle is..... idle.

Sun Mar 13, 2011 8:23 am

Yep Matej, sorry I didn't dig so far into the old posts

BTW, it's quite annoying to see this problem has been reported so long time ago and not solved yet. Looks like a polling issue so it should be easy to fix IMHO...

Sun Mar 13, 2011 8:39 am

This is not a big deal, but yeah, it should be looked into. Basically:

* if you start Octane and don't touch anything, there is no CPU usage
* the moment you enter and exit a menu (any menu), Octane starts to use one core at 100% and it will continue to use it until you close the program
* every time you are inside a menu, the usage will drop back to zero, when you exit the menu, will raise back to 100%

All this happens without loading a scene.

Steve, sorry, this is a Linux exclusive

Sun Mar 13, 2011 8:43 am

matej wrote:* if you start Octane and don't touch anything, there is no CPU usage

I'm getting the 100% CPU usage as soon as Octane starts, without touching anything.

Sun Mar 13, 2011 8:46 am

yoyoz wrote:
matej wrote:* if you start Octane and don't touch anything, there is no CPU usage
I'm getting the 100% CPU usage as soon as Octane starts, without touching anything.

Interesting, I have to touch something first (like open a menu or toggle preview tabs in Node inspector)

Sun Mar 13, 2011 12:03 pm

One plus point for windows. It had to get one eventually.

Mon Mar 14, 2011 12:45 am

Just booted over to my Ubuntu and tried on both 2.43 and 2.44. My experience mimics MateJ's. No resource useage until a menu is poked, then one core pegs.

radiance · Tue Mar 15, 2011 2:28 am

when we did our linux port early last year, we ran into several threading / locking issues with X11,
which required a copious amount of Xlocks to be added to the GUI library.

I am pretty sure this is the messaging manager that simply spins in a loop, and at various times calling X locks,
which cause quite a bit of additional system call load.

Can someone post some detailed 'top' screenshots so we can see the type of load it generates ?

Unfortunately it's not easily fixed, as the developer of the GUI lib has already commented on it by saying he does'nt use linux,
and i have no clue where to start looking in his haystack of code. (this was early last year)

We need to upgrade it though, and newer versions might fix this.
However due to a few customizations, we can't simply build with a new version,
so it's not something i like doing when there is no clear problem,
but this could change that.

Any way, we are currently swamped with more severe stuff to fix/implement. (rewrite of multi-gpu render core, new kernel and much else),
so I think you will have to tolerate this for another few months...

Radiance