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Richard Hagen avatar image
Richard Hagen asked ·

CPU Affinity

I was wondering how Arnold handles CPU affinity settings? Does it override them based on the settings in the render globals?

I'm trying to set CPU affinity through my render manager program.. Whenever I render using Maya or kick itself, the render process resets its affinity back to full power.

I'm asking the rendermanager vendor directly, but I'm asking here because I was wondering if Arnold 5 / MTOA 2 does things differently. You might wonder why I would want this at all, and its because I run this stuff in a school and have no choice but to run background renders on every station just to get the volume of work done.

forgot to state I'm using MTOA 2.0.2.4 and maya 2017u4 and 2018u1 (same results with both)

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Stephen Blair avatar image
Stephen Blair answered ·

On Linux, pin_threads works. It doesn't do anything anymore on Windows, because we have to set affinity to support large numbers of threads.

If the render manager knows how many CPUs to allocate, can it just use that number on the batch render command line?

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Darren James avatar image
Darren James answered ·

Having the same problem too really anoying had it working once using cpu lassoo... but it's just pins all cores on my i9....

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Richard Hagen avatar image
Richard Hagen answered ·

Just as a confirmation for reference, I manually sent out a frame with the rendermanager, specifying threads and it works as you said it would.

"C:\solidangle\mtoadeploy\2018\bin\kick.exe" -nstdin -dw -dp -nocrashpopup -i "\\prod\class\rhagen\data\Mia_museumwalk04.0011.ass" -o "\\prod\class\rhagen\images\mia\museum0013.exr" -v 4 -set options.abort_on_license_fail true -set options.threads -24 -l C:\solidangle\mtoadeploy\2018\shaders

As an observation on having a kick render ramp up and down CPU while it is rendering ... I can absolutely do it manually with Task Manager, but I'm having problems doing it with the rendermanager, so I think it is something that the vendor has to look at doing. Thank you for the help!

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Richard Hagen answered ·

the problem lies with it needing to be dynamic on Windows. If someone is on a station I want to be able to set the render to, say, 4 cores.. Then, when the user logs out, use all 48 cores. Is there some switch that can be used (perhaps unsupported) that turns this feature back on in Windows, just to see what happens? I can't go back to using Arnold 4, that's for sure. At any rate, at least I know you've changed things.. but you should mention this on your support wiki sites.

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If you can do all that, why can't you set the number of threads on the command line?

Are you saying that with Arnold 4, an in-progress render would change from using 4 cores to 48 during the render? I did not think that was possible.

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Richard Hagen avatar image
Richard Hagen answered ·

the rendermanager software is using -set options.pin_threads off when it sends the kick command.. but I see that kick isnt respecting the affinity either.

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Stephen Blair avatar image
Stephen Blair answered ·

If you really must set affinity yourself, then set options.pin_threads to off.

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Richard Hagen answered ·

I'll try running it with some switches like you mentioned... as well as different versions of Maya. Right now, I'm running kick through the rendermanager software. I want the rendermanager to set the amount of CPU Arnold uses, and not hard code it by limiting arnold... reason being that I want the same job to run at 1/4 power, UNTIL until the person logs off... at which point it will ramp up to full power.

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Stephen Blair answered ·

You can limit the number of threads used by Arnold for the render. If you limit Arnold to half the threads, for example, does it matter about the affinity?

Maya 2018 seems to reset the affinity. It happens with other renderers too.

How are you testing kick and affinity? If I run kick with -ipr m -t 6 and then set the affinity, the affinity doesn't change when the ipr updates.

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