The issues about architecture of the COLO checkpoint

[Daniel Cho]

Hi everyone, 

     We have some issues about setting COLO feature. Hope somebody could give us some advice.

Issue 1:

     We dynamic to set COLO feature for PVM(2 core, 16G memory),  but the Primary VM will pause a long time(based on memory size) for waiting SVM start. Does it have any idea to reduce the pause time?

Issue 2:

     In https://github.com/qemu/qemu/blob/master/migration/colo.c#L503, could we move start_vm() before Line 488? Because at first checkpoint PVM will wait for SVM's reply, it cause PVM stop for a while. 

     We set the COLO feature on running VM, so we hope the running VM could continuous service for users. 

Do you have any suggestions for those issues? 

Best regards,

Daniel Cho