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Mildly interesting multiprocessing quirk
Hello
I just performed a render from AE CS5 using multiprocessing (AE used 10 cores), and the resulting movie had 8 good frames, 2 frames with the ‘footage missing’ color bars on one of the elements (a PSD file), then 8 good frames, the 2 bad ones, 8 good, 2 bad…etc. etc. It was as if 8 cores loaded the PSD file successfully but 2 cores didn’t.
Not really a problem – I just re-rendered it with multiprocessing off and it was fine. Just kinda interesting…although would have been a pain if it was a huge, hours-long render! ‘Twas only a 3 minute render.
So there you go. That’s the highlight of my morning so far. Other than a chocolate chip bagel.
Oh yes, forgot to mention – OpenGL is off.
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2 Replies
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I’ve got 12GB (it’s going to be a much more AE-friendly 32GB very soon), with 0.75 GB per processor.
Thanks for the link to that recommended memory page – I’d seen it before and thought “when I get around to it I’ll check that out and run some tests”. Well, now’s the time!
I’m not going to be using my previous settings – my test render came in at 6m 44sec + 15sec prepping background tasks before the render started. Multiprocessing OFF = 5m 52, but with the recommended settings (and multiprocessing ON) it took just 4min 45secs – a third off!
Most of my projects are kinda similar, so these settings should work for me from now on. Thanks, Dave for prompting me to do this!
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I’ve been experimenting with settings on my 12 core with 32 GB. Most Comps render and preview faster when I use multiples of 3 for the number of cores (12, 15, 18 etc) and give After Effects RAM in multiples of 3 GB. Each proc gets 1 gb at the higher settings (wish I had 64 😐 )
This may be due to the memory pipeline inherent in the Nehalem processors, 3 channels of memory.
Not sure whether these settings are just voodoo or whether this is fact, however tests on the same comp with a variety of MP settings bear this out for me.
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