Fusion freezes, saturates efficiency cores only on M2, then resumes

[rprovideo]

Hi

I was finally able to do a meaningful recording about this. I had this really annoying on a big model I work on, where sometimes more complex actions like save, undo, or selecting a bigger chunk of the model can freeze Fusion for 5-10 minutes.

I had this on my Macbook M1 and it was so annyoing I bought an M2, which is lighting fast. Mind you, sometimes this does not happen at all, the other day I had a big assemlby model, which is over 200MB and is usually painfully slow, work for an hour without any problems. When I opened it the next day (after some component changes) it was again back to one action every 10 minutes.

Today I was working on a relatively simple model, (which I can share privately) and was able to capture signs of the problem. I was doing actions in the drawing space that I see tripping the model up, like changing wireframe and paper size.

You can see that some actions take a long time, and give me the old wristwatch icon. None of them increase CPU or GPU pressure, though.  However, when I change the sheet size, the machine gives me a beachball. Then suddenly all the powerful Performance cores shut down, and the Efficiency cores saturate fully. The Activity monitor indicates the software is not responding. After a while, though, it exits whatever loop it was, and does the job.

Sometimes I saw the wristwatch icon to come up for a minute, then suddenly all the efficiency cores go up, but only for a second, and bam, the job is finished.

for some reason it wont let me insert a screencast, but here is the link: https://autode.sk/3BZqDPo

also I saw when the screencast was compressed, a similar thing, except only the performance cores went up, the activity monitor would say screencast uses a lot of CPU, but it was not red, and it was done in 3 seconds. 

it seems to me somehow Fusion wants to use the low-end cores, and kills them, not using the machine in its fully potential, while the other autodesk product does.

[rprovideo]

here is a screenshot of it making a second projection. This time it uses all the cores briefly, and finished the operation. Mind you, then I did it again, and then it only used 1 of the performance cores, and did it so bad I had to force quit. It did these spikes and then stopped the CPU but never gave back the cursor for about 10 minutes. 

[rprovideo]

anybody?

[ClintBrown3D]

Hi @rprovideo 

Are you running Fusion using Rosetta? Or is it just natively installed on your mac?

[rprovideo]

unfortnately, Autodesk has not ported Fusion to native apple architecture yet, so the only option is to run thru rosetta. Which I have to say, 80% of the times is really fast. This must be some sort of cpu allocation bug, but I am not knowledgeable enough to say.