Only one processor Rendering

[Matt Callac]

[Kevin Camp] “it’s hard to tell what’s breaking the multi-frame rendering or the multi-threaded processes… you’d need to go through a comp layer by layer and doing a test render to find out which layer(s) are causing the issue. then you may even need to go through effect by effect to find out if it is an effect.”

Effects was easy to do, as there weren’t that many effects. Went layer by layer deleting and test rendering and never found the problem. I guess i’ll try that again, and look into what breaks multithread processes.

thanks

-mattyc

[Andrew Somers]

Matt said: ” It’s still using all of your processors, but it’s using them to render each frame individually (not multiple at the same time). “

No Matt, this is not a correct assumption. Even multi-threaded code will not neessarrly take advantage of all processors – a fact that becomes clear as you add processors. Even with a multi threaded app, when you go from 2 ores to 4, and 4 cores to 8, you will see an overall reduction in core utilization.

One way around this is to launch multiple instantiations in the background, so that each instantiation can take advantage of the unused processor time that other instantiations are not using, and also make more efficient use when dealing with single-threaded operations.

This is the reason that “render multiple frames simultaneously” was added as a feature.

EVEN SO – there are effects that will not multi thread, and I believe even some that will not work with muilt-processing at all.

In the jpeg you posted, it appears that you have something that is operating as a single thread. Not seeing your project, it’s hard to know what/why – but don’t assume that everything – plugin/effect what have you – is multi threaded.

ALSO, when posting images of activity monitor, the “System Memory” tab usually has some of the best clues.

Try This:

STEP ONE: Quit all other apps and log out (or reboot), then log back in and *only* start After Effects.

STEP ONE: Turn Multiprocessing ON. Since you only have 16 GB of RAM, limit the processors to 4, and set each to 2GB of RAM. Set “reserved for other apps” to 4 or 5 GB.

This should launch 4 background instances and you should then be rendering with 4 cores. You *may* be able to increase the number of cores, but generally (in practice) 16 GB is really only enough for efficient use of 4 to 5 cores when using MP. If not, then you may be using one of the effects that drags AE down to a single threaded situation. Without knowing your project or effects chain, it’s hard to say.

[Matt Callac]

[Andrew Somers] ” Even multi-threaded code will not neessarrly take advantage of all processors – a fact that becomes clear as you add processors. Even with a multi threaded app, when you go from 2 ores to 4, and 4 cores to 8, you will see an overall reduction in core utilization.”

thanks for that clarification.

[Andrew Somers] “Turn Multiprocessing ON. Since you only have 16 GB of RAM, limit the processors to 4, and set each to 2GB of RAM. Set “reserved for other apps” to 4 or 5 GB.”

Just ran this test and when I look at the activity monitor the 4 BG instances are are shooing .5% CPU usage, while the main AE ap is using 120%. This nearly quadruples the expected render time.

[Andrew Somers] “Not seeing your project, it’s hard to know what/why – but don’t assume that everything – plugin/effect what have you – is multi threaded.”

Even when i turn off all the effects (which are minimal), it still has the same result.

I got everything rendered out overnight last night, there were 6 comps that needed to render. Each comp is built the same way but utilizing different assets. The first one took 2 hours the second took 1.5 hours, then the other 4 took about 30-40 minutes each. I set up a second machine to render comps from as well, and started in reverse order just in case things were still rendering when i got in. The first comp on that machine (which was the same as the last comp on the other machine) took 1.5 hours to render the second took 1 hour, and the remaining comps took 30-40 minutes each.

I’m clueless as to what is causing this weirdness. It does seem that something going on in the project is killing multithread processing, but i have not been able to figure out what.

Thanks again for your posts.
-mattyc

[Darby Edelen]

[Matt Callac] “I’m clueless as to what is causing this weirdness. It does seem that something going on in the project is killing multithread processing, but i have not been able to figure out what.”

AE might be starved for memory, this can lead to all kinds of strange goings-on.

There are lots of things I’d recommend looking at, including memory usage in Activity Monitor, available disk space on your OS drive (used for virtual memory), location of your disk cache (if you’re using one).

What resolution and bit depth are you working at? If you’re using any footage items, what kind? What effects are you using?

Darby Edelen

[Matt Callac]

[Darby Edelen] “There are lots of things I’d recommend looking at, including memory usage in Activity Monitor, available disk space on your OS drive (used for virtual memory), location of your disk cache (if you’re using one).”

Not using a disk cache, and there’s 500 free gigs on the system drive. without having multiframe rendering on AE was using just over 11GB of memory.

[Darby Edelen] “What resolution and bit depth are you working at? If you’re using any footage items, what kind? What effects are you using?”

Rendering out full res 1080 and i’m working in 8bit colorspace. effects are pretty minimal
add grain
ramp
levels
calculations
Curves
tint
CCRepetile
and stroke

-mattyc

[Cassius Marques]

I’ve had the same thing on a project of mine yesterday… I’ll try to narrow it down also… will post if I find something… Ae 5.5 too.

[Matt Callac]

Today I finished up some of the prep work for final renders. And somehow the problem has sort of gone away.

THe only 2 real major things i did was adding trapcode’s horizon to each scene to add a 3D sky to the scene. I had 35MB tiff file just dropped into the comp’s in the BG without adding Horizon. The second thing I did was add an elliptical mask to the ground layer so at certain camera angle’s i wouldn’t get sharp conners at the horizon. The ground layer is a precomp full of vector artwork with the collapse transformations switch on.

While i wouldn’t think either one of those changes would have affected multithread processing apparently they did. And 7 of the comps have rendered out on all processors.

The problem is mostly gone i say b/c the 8th comp is 2.5 hours in with 4.5 hours left, and it’s limping away on one processor. So something is still wonky in that comp. The other comps rendered in roughly a half hour each.

-mattyc

[Andrew Somers]

Matt: Just ran this test and when I look at the activity monitor the 4 BG instances are are shooing .5% CPU usage, while the main AE ap is using 120%. This nearly quadruples the expected render time.

This sounds like you are choked for RAM.

Is your disk cache turned on? It should be set to 20 GB or so.

[Matt Callac]

[Andrew Somers] “Is your disk cache turned on? It should be set to 20 GB or so.”

I’ll make that change and see how it goes. Thanks for the tip.

-mattyc

[Matt Callac]

[Andrew Somers] “This sounds like you are choked for RAM.

Is your disk cache turned on? It should be set to 20 GB or so.”

Just went to check disk cache and it was already on and set to 20GB

-mattyc