Performance on farm rendering

[steven talbott]

I have an odd question for those that may be in the know on the inner workings of the render farm. I have two computers, a desktop and a laptop.

 

Laptop specs :

Processor : Intel Core I7 Cpu Q740 @ 1.73Ghz

Ram : 6Gb

 

Desktop Specs:

Processor : Amd Phenom II x4 945 Processor 3.00 Ghz

Ram : 8GB

 

Both are running render farm and are working on one project right now. My question is does the nxt render farm work multithreaded and multicore? If not is there a way to enable it under Windows 7? The reason I ask is that I have been watching the cpu usage for the last 20-30 min of it rendering. The desktop has been averaging at about 25% with a once in a blue moon spike to 100%. The laptop has been averaging about 13% cpu usage with occasional spikes to 86. Is this natural for it? If so is there a way to force it to take advantage of the rest of the cpu usage that is just waiting dormant? If not is it something in development?

 

 Thanks,

Steven Talbott

[Roy Hirshkowitz]

Depends a little on the project.  You're most likely to see this type of CPU usage pattern if you're rendering at low-res (an animation, perhaps.)  Try a higher res. image as a test case and see if you get more CPU usage.  The farm has the same engine as the interactive (normal AccuRender)version-- so in general you should see similar patterns. It's quite greedy, so it's supposed to take everything available.

[steven talbott]

The 2 images in question actually are high resolution 5760x3240. They average out to about 8 megs jpg when stitched together. I figured that would be high enough. Its a render of a playground with a couple trees in background. I can attach it later tonight if you want but I figured that high a res would eat the cpus alive.....

[Roy Hirshkowitz]

Ah-- try a smaller one-- say 1024 x 768 and see what happens to the cpu usage.  It's possible, with so much data flying around, that you're seeing either some paging on some machines or some network bandwidth problem.

[steven talbott]

Testing as we speak on the desktop machine with 1024x768 and its pinging all over the place, starts out a lot in the 30% range, some 60ish and once or twice have seen it hit 90%. I know its not an issue of bandwidth on this one because the network share is on this same drive. Paging I can believe  but would have thought this smaller file was less so........

 

Ok now its 3 parts in and was hitting high 90s but it seems to be very random as to how much it uses. Only lasted maybe a minute then dropped to about 40%.

 

I will attach the picture once it's done here in a few minutes so you can tell me if it's just not a complicated enough scene.

[steven talbott]

Here's the test jpg

[Roy Hirshkowitz]

Ah-- so your scene has an area which will take much longer than others-- basically the scanlines which include the trees.  It's likely accounting for some of what you're seeing-- where some threads are just taking a lot longer to complete.  Just for grins you can run the path tracer and see if you get slightly different load balancing.

This sounds like pretty normal behavior-- I probably wouldn't worry about it.  Most scenes peg all of your processors-- I have 12 and they're routinely pegged (most of the time.)

 

Nice image, BTW.