Ticket #7796 (new defect) — at Initial Version

Opened 10 years ago

Last modified 4 years ago

Iffy serial port cause >95% CPU usage in a VM

Reported by: jimoe Owned by:
Component: uart Version: VirtualBox 3.2.12
Keywords: Cc:
Guest type: other Host type: Linux


opensuse v11.3

linux x86_64

USRobotics FAX/modem 5637

The serial port is enabled and set for COM1. The "Port Mode" is set to "Host Device" and the "Port/File Path" is USBACM0.

When the VM starts up, it complains that the COM port is "iffy" (paraphrase) and may not work. It does in fact work and quite well. However, the VM is spinning in a loop somewhere because the CPU usage for one core (of a quad processor) averages about 95%. Good thing it's a quad core CPU. The actual core in use switches around but at any one time a core is running close to maximum. The CPU usage within the VM guest itself is normal, less than 5%.

If I disable the serial port, the VM's CPU usage drops back to normal (5 - 10%).

Change History

Changed 10 years ago by jimoe

Log file of the VM that uses lots of CPU time doing nothing

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