On 6/12/12, Stefan Hajnoczi <stefanha@xxxxxxxxx> wrote: >> After some testing, the only steps needed are >> 1. VMM add physical host usb device -> select storage to guest >> 2. VMM remove hardware >> 3. Physically remove the USB storage from the host, thread/core >> assigned to guest goes 100% > > Two clarifications: > > 1. Can you confirm that the 100% CPU utilization only happens in Step > #3? For example, if it happened in Step #2 that would suggest the > guest is entering a loop. Step #3 suggests the host is entering a > loop. Yes, it's confirmed that #3 has to be done. I've top running in both guest and host when replicating this. If left physically attached to the host machine, nothing unusual happens. The change in load level is almost immediate upon physical removal. Within the guest, the loads are basically 0, single core very lightly loaded guest. In the host, top shows 100% cpu utilization on the relevant qemu-kvm process. Unfortunately, I did not think to use the (1) key to display the individual physical core so can't say if it was really just loading on that core. The only thing possibly relevant data is that on the SLES set, I had the VM pinned to a specific core, the VMM gui shows a load graph of only 25%. On the Centos 6.2 set, it was not pinned specifically and the load graph goes to 100%. But in both cases, top output shows 100% for the process. > 2. Please run top(1) on the host during high CPU utilization to > confirm which process is causing high CPU utilization. Not physically at the machines now so I can only verify this tomorrow. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
