problems with multi-threaded rendering

[jamie]

Hi all,

I'm having problems when I want to use more than one CPU to render with mental ray. I'm having this issue with standalone 3.9 and 3.10, as well as with mental ray for Maya 2012. mrforMaya2011 seems to be okay.

If I kick off a non-iray job in mental ray standalone 3.9 or 3.10, it'll run for a while, then segfault. The segfault doesn't occur at the same place every time - sometimes I'll get several frames rendered and sometimes it happens during the first frame. Nor does it always segfault at the same place in the render process - sometimes it's during final gather, sometimes during the rendering, sometimes other. (iray is working well in 3.9. I'm having a separate issue with it in 3.10, which I may detail in a different post, after I look into it a bit further.)

When I render within Maya 2012 with mental ray, and specify more than one CPU, the whole program freezes up at some point during the render and I have to kill Maya from the command line. The progress reports "RCMP Info: flushing 32484 bytes" over and over again until I kill the process.

I'm on a Linux 64-bit platform, 96 total CPUs. So you can see why I don't want to use them one by one. =)

Any ideas as to what may be happening?

Thanks!

Jamie

[Remydrh]

I don't know the segmentation fault, lots of different things can cause that. If you can reduce it to a specific object causing the segmentation error and export a .mi that reproduces it, attach it here.

The other error is you're out of memory and it panics.

You have 96 CPUs but not enough memory to hold the scenefile? Seems oddly lopsided. How much memory do you have? Is the file large? Lots of textures?

[gunter]

Jamie, what exactly means "more than one cpu" in your case ? Does it crash with 2 cpus ? Could you please
try a run with -threads <some low number.. for example 12> ?

Gunter

[jamie]

Hi,

Yes, I do get segfaults with two CPUs. Let me check on the memory requirements - I've tried this with a couple of scenes of varying complexities, but let me make something really trivial and try it with that, too.

Thanks!
J

[juri]

Jamie, please try to set stirng option "finalgather legacy" on and check if it helps. The RCMAP message is coming from the new map container used for finalgather maps, which had some issues.
This was fixed in 3.10, but may be you are using an old version, could you send the full version number?

Best regards,
Juri