[libvirt-users] libvirt API hangs

Hi, I have someVMs in my KVM hosts(RHEL 5.5), I found when run "virsh save <domain> <file>" to save a VM, the command "virsh dominfo <domain>" will hang until the save command finishes. Is this libvirt's behavior? Or KVM/QEMU's? This may impact the performance. Thanks, Qian