Not using all the CPU cores?

[saccade]

Recently I was updating a Fusion 360 drawing from the original design. The design has some large mesh objects in it, so the update takes a while. I was pleased to see Fusion using several of the CPU cores for the task, but it wasn't using all if them. The cores it was using were the low-performance "efficiency" cores (#17-32 on my i9-13900K), not the faster "performance" cores 1-16 (really 1-8, but hyperthreading). Not sure if this is a Fusion issue or a Windows 11 issue, but I've seen it happen multiple times.

Please, when you're making me wait for a Fusion command to complete, feel free to use all the CPU resources your app can get its hands on!

Oh, and your regular reminder that I have a really expensive RTX-4080 just sitting there, waiting for Fusion to take advantage of it! Would be nice to render in two tenths of a second instead of two minutes.

[HughesTooling]

Edit. Reading your post again and I see you are using Win 11 so not sure what to suggest. If you do a search on google about this problem you'll find a lot of problems with games as well. Don't know if setting the PC up for max performance would help.

This has come up before and apparently the OS is in charge of this. From what I could find Windows 10 has no control but Win 11 should use the performance cores.

[lance.carocci]

By design, the OS is supposed to handle core scheduling for apps. There are some third party tools out there to force processes to use specific cores, but generally speaking it's something the app can only influence, not override.

We regularly upgrade our use of various threading APIs, and I hope newer versions will better address the issue of using E cores, but at the moment it is something only Intel and Microsoft can truly control - otherwise, we'd probably be on P cores at all times, and that's exactly what they don't want apps doing.

[sascha_loth]

hello

im performing a similar operation currently (editing a sketch dimension early in the pipeline) and updateing the entire model only seems to utilize a single cpu core. I wouldt have commented but i also play a game (counterstrike 2) and that game recently got an update which lets you control wether the game shall use performance or ecores (or both). So it should be possible to do somehow.

windows 11 on a Intel Core ultra 7 265K

[lance.carocci]

Those particular operations are largely single-threaded floating point recalculations, so unfortunately they benefit more from a raw increase in clockspeed more than they do additional cores and threads. This is not the case for all of Fusion, it just depends on the command; toolpath simulation, for example, is multi-threaded.

[TrippyLighting]

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@sascha_loth wrote:

... So it should be possible to do somehow.

...

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That is a common misunderstanding!

Certain mathematical operations and algorithms don't lend themselves to parallel processing.

[TimelesslyTiredYouth]

Fusion is primarily optimized for single threaded tasks (1 core at a time), I'm pretty sure the only exception to this is rendering and simulation, and there's a setting in rendering you can change for this purpose, however don't quote me on the redering setting, I don't use rendering often. And I think during simulation it can occur with multiple cores, the only way I'm thinking is if you go to Task manager go to Fusion, and (I think it's called) set affinity to Fusion, you can assign cores to the app, I did this once before with another application

Regards

Ricky