For optimum I/O performance it's critical to make sure that Windows guests use the Hyper-V reference counter feature. QEMU command line should include -cpu ...,hv_time and -no-hpet
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Analyzing my command line I see the "-no-hpet" but I dont see the "hv_time"See below full comand.Any hints?Thanks,Gianluca
/usr/libexec/qemu-kvm -name guest=testmig,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-12-testmig/master-key.aes -machine pc-i440fx-rhel7.3.0,accel=kvm,usb=off,dump-guest-core=off -cpu Westmere,vmx=on -m size=4194304k,slots=16,maxmem=16777216k -realtime mlock=off -smp 2,maxcpus=16,sockets=16,cores=1,threads=1 -numa node,nodeid=0,cpus=0-1,mem=4096 -uuid x-y-z-x-y -smbios type=1,manufacturer=oVirt,product=oVirt Node,version=7-4.1708.el7.centos,serial=xx,uuid=yy -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-12-testmig/monitor.sock,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=2018-02-09T12:41:41,driftfix=slew -global kvm-pit.lost_tick_policy=delay -no-hpet -no-shutdown -boot strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x5 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x4 -drive if=none,id=drive-ide0-1-0,readonly=on -device ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -drive file=/rhev/data-center/ef17cad6-7724-4cd8-96e3-9af6e529db51/fa33df49-b09d-4f86-9719-ede649542c21/images/2de93ee3-7d6e-4a10-88c4-abc7a11fb687/a9f4e35b-4aa0-45e8-b775-1a046d1851aa,format=qcow2,if=none,id=drive-scsi0-0-0-1,serial=2de93ee3-7d6e-4a10-88c4-abc7a11fb687,cache=none,werror=stop,rerror=stop,aio=native -device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=1,drive=drive-scsi0-0-0-1,id=scsi0-0-0-1,bootindex=1 -drive file=/rhev/data-center/ef17cad6-7724-4cd8-96e3-9af6e529db51/fa33df49-b09d-4f86-9719-ede649542c21/images/f821da0a-cec7-457c-88a4-f83f33404e65/0d0c4244-f184-4eaa-b5bf-8dc65c7069bb,format=raw,if=none,id=drive-scsi0-0-0-0,serial=f821da0a-cec7-457c-88a4-f83f33404e65,cache=none,werror=stop,rerror=stop,aio=native -device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0 -netdev tap,fd=30,id=hostnet0 -device e1000,netdev=hostnet0,id=net0,mac=00:50:56:9d:c9:29,bus=pci.0,addr=0x3 -chardev socket,id=charchannel0,path=/var/lib/libvirt/qemu/channels/421d6f1b-58e3-54a4-802f-fb52f7831369.com.redhat.rhevm.vdsm,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.rhevm.vdsm -chardev socket,id=charchannel1,path=/var/lib/libvirt/qemu/channels/421d6f1b-58e3-54a4-802f-fb52f7831369.org.qemu.guest_agent.0,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel1,id=channel1,name=org.qemu.guest_agent.0 -chardev spicevmc,id=charchannel2,name=vdagent -device virtserialport,bus=virtio-serial0.0,nr=3,chardev=charchannel2,id=channel2,name=com.redhat.spice.0 -spice tls-port=5900,addr=10.4.192.32,x509-dir=/etc/pki/vdsm/libvirt-spice,tls-channel=default,tls-channel=main,tls-channel=display,tls-channel=inputs,tls-channel=cursor,tls-channel=playback,tls-channel=record,tls-channel=smartcard,tls-channel=usbredir,seamless-migration=on -device qxl-vga,id=video0,ram_size=67108864,vram_size=8388608,vram64_size_mb=0,vgamem_mb=16,max_outputs=1,bus=pci.0,addr=0x2 -msg timestamp=on