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kshetline
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Frequent VERY slow boot-up times for VM (macOS host, Windows 11 guest)

My host system is an Intel iMac Retina 5K, 10 core i9, running at 3.8GHz, with 64GB of RAM, 2TB SSD. I'm running VMWare Fusion Pro 13.0.0.

At least half of the time I boot up a Windows 11 VM (and I've created at least 3 from scratch now), the spinner on the Windows start-up display freezes for a very long time, even as long as about half an hour. The first time this happened I was sure the VM had crashed, but after walking away to wait it out the next time, I discovered that I just had to be very patient with the boot process.

Once, when a reboot actually did crash, the extreme slowness was very evident: A Blue Screen of Death appeared, but only after the display was filled with blue one small block at a time, and after the screen was filled with blue, I could actually see characters in the error message individually rendered, stroke by stroke, one at a time.

While this is happening host CPU usage for VMWare runs around 450%, with 8 cores assigned to the VM .

Once boot-up eventually succeeds, however, everything runs smoothly. Sometimes shutdown can be slow too, but that problem doesn't happen as frequently.

I'm wondering now if there can be something wrong with my macOS host system itself that causes virtualization problems in general, no matter what virtualization software I'm using. I switched to using VMWare from Parallels to solve a different performance problem, but only with nested virtualization -- trying to run Docker Desktop would max out host CPU usage for Parallels at nearly 1000% (10 cores assigned), and the Windows guest would become almost entirely unresponsive, taking half a minute or more simply to accept individual keystrokes.

Parallels VMs never suffered from the slow boot times I'm seeing with VMWare, just the horrible nested virtualization with Docker.

Is there some sort of general macOS virtualization tune-up or performance fix I can perform? I'd rather not reinstall my OS, but it might come to that if I can't figure out anything else to try.

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Technogeezer
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Which Windows 11 edition are you running?

What macOS version on the host?

If you finally get the VM to open, how many CPUs does it say you have?

Two other thoughts.

Depending on the Mac model you have, it might not have a CPU that has supports the VMCS Shadowing feature. If that feature doesn't exist on the CPU chip, Fusion will implement equivalent features in software, which degrades performances. Turn off "allow hypervisor applications in the virtual machine" and "enable IOMMU" and see if there's any change in speed. 

Also, make sure that Windows hasn't turned on Memory Integrity in the VM. If it has, try turning it off and see if symptoms change.

You might want to attach a copy of the vmware.log file to a reply - it has info about both the OS version and the exact Intel CPU model you're running.

 

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kshetline
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@Technogeezer wrote:

Which Windows 11 edition are you running?

22H2.

What macOS version on the host?

Ventura 13.0.1.

If you finally get the VM to open, how many CPUs does it say you have?

4.

Two other thoughts.

Depending on the Mac model you have, it might not have a CPU that has supports the VMCS Shadowing feature...

This is a 2020 10-core i9 iMac, so I doubt that's an issue. Besides, boot up isn't always slow. And when it is slow, it can be pathologically slow, not just "oh, things aren't optimal" slow. I doubt the software fallback slows things down so much you would see characters rendering on the screen one at a time in an error message that normally flashes onto the screen within a single video frame.

Also, make sure that Windows hasn't turned on Memory Integrity in the VM. If it has, try turning it off and see if symptoms change.

It's turned off.

You might want to attach a copy of the vmware.log file to a reply - it has info about both the OS version and the exact Intel CPU model you're running.

I'll check into that.

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dempson
Hot Shot
Hot Shot

[Edited some details to correct processor speed and list another possibility.]

Assuming my sources have the details right, the 2020 27-inch iMac with a 3.6 GHz 10-core i9 has a Core i9-10910.

The iMac with a 3.8 GHz 8-core i7 has a Core i7-10700K.

There is no 3.8 GHz Core i9 so I'm not sure which detail you have wrong.

VMCS shadowing is part of the vPro feature set. According to https://ark.intel.com, the Core i9-10910 is the only processor option for the 2020 27-inch iMac which does NOT have vPro, therefore cannot do VMCS Shadowing, so cannot do efficient nested virtualisation in VMware Fusion on macOS Big Sur or later. The Core i7-10700K does have vPro.

There was a similar situation with the 2019 15-inch and 16-inch MacBook Pro, where of the three available processor options, only the middle one had vPro (and VMCS shadowing). Those who bought the most expensive CPU missed out. 

To confirm which processor is in your iMac, use the following command in Terminal:

sysctl -a|grep brand

The output should resemble this (from my 16-inch MacBook Pro):

machdep.cpu.brand_string: Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
machdep.cpu.brand: 0

In your case I'd expect to see an "Intel(R) Core(TM) i9-10910 CPU @ 3.60 GHz" or "Intel(R) Core(TM) i7-10700K CPU @3.80 GHz".

You can then use https://ark.intel.com to find the specifications for your processor and see whether the page mentions "vPro". If that text appears it should be a line in the table which says "Intel vPro® Eligibility" with a value of "Intel vPro® Platform". If you see that text, then your processor supports vPro and by extension VMCS shadowing.

If you cannot find a line mentioning vPro then your processor does NOT support vPro or VMCS shadowing.

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kshetline
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@dempson wrote:

[Edited some details to correct processor speed and list another possibility.]

Assuming my sources have the details right, the 2020 27-inch iMac with a 3.6 GHz 10-core i9 has a Core i9-10910.

The iMac with a 3.8 GHz 8-core i7 has a Core i7-10700K.

There is no 3.8 GHz Core i9 so I'm not sure which detail you have wrong.

I should have said 3.6 GHz. (I was checking remotely, and on a scaled-down VNC view a blurry 3.6 looked an awful lot like 3.8.)

To confirm which processor is in your iMac, use the following command in Terminal:

sysctl -a|grep brand

The output should resemble this (from my 16-inch MacBook Pro):

machdep.cpu.brand_string: Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
machdep.cpu.brand: 0

In your case I'd expect to see an "Intel(R) Core(TM) i9-10910 CPU @ 3.60 GHz" or "Intel(R) Core(TM) i7-10700K CPU @3.80 GHz".

It's the i9-10910 that I have, and you're right that VMCS shadowing is not supported.

Still, I'd expect this would be a "gosh, this seems a little sluggish" performance hit at most, not something that makes boot times randomly up to a 100 times slower than they should be.

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