Tell Mr How Many Processors To Use?

[douens]

When I use batch render with maya SW render I tell maya how many CPU's to use: Render > Batch Render > Options > Number of processors to use.

However, once i switch my Render Settings to MR, I lose the ability to dictate how many CPU's I can render with. I understand MR uses settings specified in the Render Settings, but there is no place to specify how many CPU's in the GUI

this is what i've found thus far:
SW: in order to control the number of cpu's, you use: -numProcs(-n)
MR: in order to control the number of threads you use: -renderThreads(-rt)

What flag can I use to tell MR how many processors to use?

thanks

[gmask]

-renderThreads(-rt)

[douens]

QUOTE(gmask @ 07/23/07, 04:33 PM) [snapback]270242[/snapback]
-renderThreads(-rt)

Are you sure?
In the MR documentation, -renderThreads(-rt) dictates how many threads, also, -threads: will start 1 thread for each processor in the system, the number of threads can be changed with this option (from Rendering with MR by Driemeyer).
This option does not tell MR how many cpu's to use.

any other suggestions?

[gmask]

what version of a maya are you using btw?

[douens]

QUOTE(gmask @ 07/23/07, 05:02 PM) [snapback]270246[/snapback]
what version of a maya are you using btw?

i'm using 8.51

[joojaa]

You cant, you can only say how many threads there are. All in all its the same thing.

The difference is that its like saying do use 4 production lines (num of processors) versus saying use 4 concurrent productions. The later is smarter as then you give mental ray the chance to say how many processors to use. So if theres a situation where mentlaray does not benefit form using all 4 procs it will not need to use this. BUT even better you can now overload the system a bit by saying to use 6 threads for a 4 proc computer, this then processes the extra threads on drop failure time.

Note for well designed computation hyper threading does not necessarily constitute as a full processor so mr might decide that its actually better to run the treads in different fashion for a more optimal result. You just have to trust the fact that guys at mr are better at designing parallelisms than you are. Noa a hyerthreading processor might show you a decreased percentage in your graph even tough its not true since using 100% of the power of therad one is slightly faster sometimes
as using 100% of 2 threads.

[douens]

QUOTE(Joojaa @ 07/24/07, 12:52 AM) [snapback]270280[/snapback]
You cant, you can only say how many threads there are. All in all its the same thing.
The difference is that its like saying do use 4 production lines (num of processors) versus saying use 4 concurrent productions. The later is smarter as then you give mental ray the chance to say how many processors to use. So if theres a situation where mentlaray does not benefit form using all 4 procs it will not need to use this. BUT even better you can now overload the system a bit by saying to use 6 threads for a 4 proc computer, this then processes the extra threads on drop failure time.

Note for well designed computation hyper threading does not necessarily constitute as a full processor so mr might decide that its actually better to run the treads in different fashion for a more optimal result. You just have to trust the fact that guys at mr are better at designing parallelisms than you are. Noa a hyerthreading processor might show you a decreased percentage in your graph even tough its not true since using 100% of the power of therad one is slightly faster sometimes
as using 100% of 2 threads.

many thanks joojaa, i appreciate your time and insights.