Public bug reported:
macOS version: 10.15.2
QEMU versions: 5.2.0 (from MacPorts)
5.2.92 (v6.0.0-rc2-23-g9692c7b037)
If the QEMU window is not visible (hidden, minimized or another
application is in full screen mode), the QEMU process gradually freezes:
it still runs, but the VM does not respond to external requests such as
Telnet or SSH until the QEMU window is visible on the desktop.
This behavior is due to the work of the macOS App Nap function:
https://developer.apple.com/library/archive/documentation/Performance/Conceptual/power_efficiency_guidelines_osx/AppNap.html#//apple_ref/doc/uid/TP40013929-CH2-SW1
It doesn't matter how the process is started -- as a background job or
as a foreground shell process in case QEMU has a desktop window.
My VM does not have a display output, only a serial line, most likely if
the VM was using OpenGL, or playing sound (or any other App Nap
triggers), then the problem would never have been detected.
In my case only one starting way without this problem:
sudo qemu-system-x86_64 -nodefaults \
-cpu host -accel hvf -smp 1 -m 384 \
-device virtio-blk-pci,drive=flash0 \
-drive
file=/vios-adventerprisek9-m.vmdk.SPA.156-1.T.vmdk,if=none,format=vmdk,id=flash0
\
-device e1000,netdev=local -netdev
tap,id=local,ifname=tap0,script=no,downscript=no \
-serial stdio -display none
The typical way from the internet to disable App Nap doesn't work:
defaults write NSGlobalDomain NSAppSleepDisabled -bool YES
** Affects: qemu
Importance: Undecided
Status: New
** Tags: app-nap freezes macos
** Tags removed: appnap
** Tags added: app-nap
--
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https://bugs.launchpad.net/bugs/1923648
Title:
macOS App Nap feature gradually freezes QEMU process
Status in QEMU:
New
Bug description:
macOS version: 10.15.2
QEMU versions: 5.2.0 (from MacPorts)
5.2.92 (v6.0.0-rc2-23-g9692c7b037)
If the QEMU window is not visible (hidden, minimized or another
application is in full screen mode), the QEMU process gradually
freezes: it still runs, but the VM does not respond to external
requests such as Telnet or SSH until the QEMU window is visible on the
desktop.
This behavior is due to the work of the macOS App Nap function:
https://developer.apple.com/library/archive/documentation/Performance/Conceptual/power_efficiency_guidelines_osx/AppNap.html#//apple_ref/doc/uid/TP40013929-CH2-SW1
It doesn't matter how the process is started -- as a background job or
as a foreground shell process in case QEMU has a desktop window.
My VM does not have a display output, only a serial line, most likely
if the VM was using OpenGL, or playing sound (or any other App Nap
triggers), then the problem would never have been detected.
In my case only one starting way without this problem:
sudo qemu-system-x86_64 -nodefaults \
-cpu host -accel hvf -smp 1 -m 384 \
-device virtio-blk-pci,drive=flash0 \
-drive
file=/vios-adventerprisek9-m.vmdk.SPA.156-1.T.vmdk,if=none,format=vmdk,id=flash0
\
-device e1000,netdev=local -netdev
tap,id=local,ifname=tap0,script=no,downscript=no \
-serial stdio -display none
The typical way from the internet to disable App Nap doesn't work:
defaults write NSGlobalDomain NSAppSleepDisabled -bool YES
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