High CPU usage after logging into screen saver in multiple monitor setup

[jernst]

MacBook Pro, OSX 10.11.6, 16G RAM
built-in Retina display, plus external (HDMI) 4k monitor
3 virtual desktops
VirtualBox 5.1.26
One VM, running Arch Linux with KDE in full screen mode in one of the virtual desktops on the external display

1. Working fine
2. I step away from the machine
3. Mac screen saver comes on
4. I return, log into the screen saver
5. The VirtualBox full screen is now "in the wrong place" along the Y axis. The top part of the virtual screen is off-screen, and there is a blank ribbon at the bottom (maybe 10-15% of screen)
6. The Mac has become sluggish, and "top" reports ~330% of CPU for the VM on the OSX side, but nothing remarkable in the Linux VM.

I can fix the "wrong place" by turning off VirtualBox full screen, and then back on. However, try what I may, I cannot reduce CPU usage:
* Suspend / resume does not change CPU usage
* Save state and restore does not either
* Only shutdown and reboot of the VM will get it back

The trouble is that the entire Mac has become unusable when this happens. And even shutting down the VM cleanly is sometimes a challenge as it takes forever for GUI apps to be responsive to mouse movements.

Is this a known issue? Workaround? Advice?

[socratis]

MacBook Pro, OSX 10.11.6, 16G RAM

Same here. If I may add, "MacBookPro11,5" in my case.

built-in Retina display, plus external (HDMI) 4k monitor

Close. Two external displays, one Thunderbolt->DVI->AppleStudio 17" (1280x1024) and one HDMI to an EIZO Flexscan (1280x1024). So, no 4K display.

3 virtual desktops

Nine and counting

One VM, running Arch Linux with KDE in full screen mode in one of the virtual desktops on the external display

Do you have the ISO name and/or link? Or a description of where to get it? Have you tried another guest?

The VirtualBox full screen is now "in the wrong place" along the Y axis. The top part of the virtual screen is off-screen, and there is a blank ribbon at the bottom (maybe 10-15% of screen)

Do you have / can you get a screenshot of this so that we're on the same page?

"top" reports ~330% of CPU for the VM on the OSX side, but nothing remarkable in the Linux VM.

I'm not sure where the CPU consuption is coming from, so could you be specific? Is "top" running on the host or in the guest? What's the process that is using the CPU? In the host or in the guest?

And finally, follow a "start the VM from cold-boot" / "observe error" / "shutdown the VM" cycle. With the VM shut down completely (not paused or saved), right-click on the VM in the VirtualBox Manager and select "Show Log". Save only the first "VBox.log", ZIP it and attach it to your response (see the "Upload attachment" tab below the reply form).

[jernst]

Here's a screen shot, downsampled as maximum upload size on this forum is 128KiB.

shot2.PNG (104.91 KiB) Viewed 1215 times

The high CPU consumption is by the "VirtualBoxVM" process on the Mac host. The Linux guest does not show anything like in its own ps.

Sorry for the delay, it decided to happen far less frquently as soon as I posted. Before that, it had annoyed me about 3 times a day for some weeks.

[socratis]

Thanks for the screenshot, but there are a couple of things missing:

• The VBox.log (zipped) for when this happens.
• The distro ISO link.
• BTW, can you make this happen at will? I.e. if you go to the Desktop and Screensaver and "Preview" the screensaver, does it happen?
• Finally, what are the settings for screensaver and power management in your host and in your guest?