Detailed rendertime script?

[Redsandro]

It's funny (not really) how precomping a lot of my layers to add some functionality changes the rendertime of my 30 second composition from 1 hour to 10 hours.
So I was wondering.. is there a way to get detailed per-layer rendertimes?

For example, could we have a script attach an expression to every layer in every precomp, and can that expression append a little something to a textfile? Or do you have a better idea?

[Redsandro]

I will raise this question again because I have to rerender some of my earlier composits for a videoclip. I am on a deadline. And right now, it takes 40 minutes per frame to render. It's just 3d layers. Not even close to fancy, just 3d. Similar shots not 3d take about 10 seconds per frame.

Is it at all possible to do some logging through a script while rendering?

[lloydalvarez]

I suspect you might be running out of RAM. Such a huge jump in render time seems to me like some virtual memory swapping is kicking in.

Lloyd

[Redsandro]

I don't think so. There's hardly any hard drive activity. I've got 8 GB of ram. Only 6GB is used when multithreading.
But there's something bottlenecking because my cores are half busy at best.

Some functions are just badly optimized and I wish there was a way to find out which ones are lagging during my renders.
For example, motion trackers are also only using one core for a mere 20%. In CS5 multithreading will probably be awesome, but even on a single core it looks like it could do better.

(This is an awesome gadget for checking on your apps: http://www.addgadget.com/all_cpu_meter/)

[lloydalvarez]

When you multithreading do you mean that you have multi-processing turned on? If so 8GB is not enough RAM to successfully use MP.

-Lloyd

[Redsandro]

Yes that is what I mean. But with it turned off, it takes even longer!

I think AE can use a maximum of 2,4 GB per core. So with 3 cores it uses 7,2 GB of memory. Am I wrong?

Remember that I am not making Avatar 2. I am just doing some multiplane rendering to simulate depth.

[lloydalvarez]

It's not that straight forward. The AE docs explain it in detail but it still sounds like to me like you are running out of RAM. Depending on how big your pre-comps are and how many instances you have you might be hitting 32bit limits regardless of how much ram you have installed. This would explain why it is slow regardless of the MP setting. Of course I am just speculating on all this, but in my experience that is usually the problem. The good news is all this will be old news once we get 64-bit in CS5

-Lloyd

[Redsandro]

So if you're right, rendering will boost massively if I render singlecore (3 GB limit) and create a 4GB RAMdrive and put my swapfile on there?

[lloydalvarez]

Again, I have not looked at your project so who knows what might be causing your slow down. But what I do know is that if you get into a memory swap situation rendering crawls to a halt so if you want to try using a ram disk then I think that would be an interesting test.

-Lloyd