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Pixar's Render Farm

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Re: Pixar's Render Farm

#41

For those that can't stand Twitter's UI: https://threadreaderapp.com/thread/1345146328058269696.html

Thank you. All I saw was a post with zero context, followed by a reply, followed by another reply using a different reply delineator (a horizontal break instead of a vertical line??), followed by nothing. It just ends. It's hard to believe this is real and intended.

It is real, probably not quite intended. Or at least not specifically designed.

Re: Pixar's Render Farm

#42

I'm surprised they hit only 80-90% CPU utilization. Sure, I don't know their bottlenecks, but I understood this to be way more parallelizable than that. I ray trace quake demos for fun at a much much lower scale[0], and have professionally organized much bigger installs (I feel confident in saying even though I don't know Pixar's exact scale). But I don't know state of the art rendering. I'm sure Pixar knows their wo…

[deleted]

Re: Pixar's Render Farm

#43

I'm surprised they hit only 80-90% CPU utilization. Sure, I don't know their bottlenecks, but I understood this to be way more parallelizable than that. I ray trace quake demos for fun at a much much lower scale[0], and have professionally organized much bigger installs (I feel confident in saying even though I don't know Pixar's exact scale). But I don't know state of the art rendering. I'm sure Pixar knows their wo…

Rendering may be highly parallelizable, but the custom bird flock simulation they wrote may be memory constrained. This is why having a solid systems team who can do care and feeding of a job scheduler is worth more than expanding a cluster.

Re: Pixar's Render Farm

#44
post #18

Earlier quoted context omitted.

That’s very much an exaggeration. Pixar/Google etc can’t run on a single desktop CPU and spends a lot of money on hardware. The best estimate I have seen is it’s scale dependent. At small budgets your generally spending most of that on people, but as the budget increase the ratio tends to shift to ever more hardware.

It is absolutely about scale.... an employee costs $x of dollars regardless of how many servers they are managing, and might improve performance y%..... that only becomes worth it if y% of your hardware costs is greater than the $x for the employee.

The issue is extra employees run out of low hanging fruit to optimize, so that y% isn’t a constant. Extra hardware benefits from all the existing optimized code written by your team, where extra manpower needs to improve the already optimized code already written by your team.

Re: Pixar's Render Farm

#46
post #3

My understanding (I am not an authority) is that for a long time, it has taken Pixar roughly an equal amount of time to render one frame of film. Something on the order of 24 hours. I don’t know what the real units are though (core-hours? machine-hours? simple wall clock?) I am not surprised that they “make the film fit the box”, because managing compute expenditures is such a big deal! (Edit: When I say "simple wall…

Maybe it’s society or maybe it’s intrinsic human nature, but there seems to be an overriding “only use resources to make it faster to a point, otherwise just make it better [more impressive?]”.

Video games, desktop apps, web apps, etc. And now confirmed that it happens to movies at Pixar.

Re: Pixar's Render Farm

#47

For those that can't stand Twitter's UI: https://threadreaderapp.com/thread/1345146328058269696.html

It's very painful to follow a conversation on Twitter. I'm not sure why they think the way they've done things makes sense.

Re: Pixar's Render Farm

#48

Can anyone comment on why Pixar uses standard CPU for processing instead of custom hardware or GPU? I'm wondering why they haven't invested in FPGA or completely custom silicon that speeds up common operations by an order of magnitude. Is each show that different that no common operations are targets for hardware optimization?

I'm "anyone" since I know very little about the subject but I'd speculate that they've done a cost-benefit analysis and figured that would be overkill and tie them to proprietary hardware, so that they couldn't easily adapt and take advantage of advances in commodity hardware.

Re: Pixar's Render Farm

#49

Can anyone comment on why Pixar uses standard CPU for processing instead of custom hardware or GPU? I'm wondering why they haven't invested in FPGA or completely custom silicon that speeds up common operations by an order of magnitude. Is each show that different that no common operations are targets for hardware optimization?

Amusingly, Pixar did build the "Pixar Image Computer" [1] in the 80s and they keep one inside their renderfarm room in Emeryville (as a reminder).

Basically though, Pixar doesn't have the scale to make custom chips (the entire Pixar and even "Disney all up" scale is pretty small compared to say a single Google or Amazon cluster).

Until recently GPUs also didn't have enough memory to handle production film rendering, particularly the amount of textures used per frame (which even on CPUs are handled out-of-core with a texture cache, rather than "read it all in up front somehow"). I think the recent HBM-based GPUs will make this a more likely scenario, especially when/if OptiX/RTX gains a serious texture cache for this kind of usage. Even still, however, those GPUs are extremely expensive. For folks that can squeeze into the 16 GiB per card of the NVIDIA T4, it's just about right.

tl;dr: The economics don't work out. You'll probably start seeing more and more studios using GPUs (particularly with RTX) for shot work, especially in VFX or shorts or simpler films, but until the memory per card (here now!) and $/GPU (nope) is competitive it'll be a tradeoff.

[1] https://en.wikipedia.org/wiki/Pixar_Image_Computer

Re: Pixar's Render Farm

#50

For those that can't stand Twitter's UI: https://threadreaderapp.com/thread/1345146328058269696.html

Thank you. All I saw was a post with zero context, followed by a reply, followed by another reply using a different reply delineator (a horizontal break instead of a vertical line??), followed by nothing. It just ends. It's hard to believe this is real and intended.

It's amazing to me that people find twitter difficult to read... I mean it's not perfect but it's not an ovaltine decoder ring, either.

Just ... Scroll ... Down ... Click where it says "read more" or "show more replies"

You're human; THE most adaptable creature known. Adapt!

I'm not saying that twitter UX is perfect, or even good. I AM saying that it is usable.

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