Libvirt vs QEMU benefits

Hello, For one of our case validation, we were using direct QEMU commands before for VM creation as it was easier to configure the VMs. Inside VM we do run the real-time latency test. Recently we switched to libvirt for the VM creation and deletion. Surprisingly, we do see a significant increase in the real-time latency performance for the VMs launched through the libvirt. W.r.t configuration wise both VMs are the same, we just converted the existing QEMU commands into libvirt XMLs. I am wondering what and all the features which libvirt has, improving this performance. Thanks, Shivakumar M