[Qemu-discuss] hv-time option doesn't improve floating-point calculation in win7 32bits os with qemu2.0.0

[研六 福州]

Hello,

 

It is refered to in qemu 2.0.0 changelog that hv-time suboption of ‘-cpu’ will improve performance of Windows guests

substantially for applications that do many floating-point or SIMD operations. (Requires KVM and Linux 3.14).

 

I want to try it so i upgrade my kernel to 3.14.1 version and add hv-time suboption of ‘-cpu’. My Guest OS is

win7 32bits and I use superpi to test floating-point performance.But I find there is no big difference between

with and without this suboption.

 

This is my qemu commad line:

/usr/local/bin/qemu-system-x86_64 -name hch_test -machine pc,accel=kvm,usb=off -cpu SandyBridge,hv-time,+erms,+smep,+fsgsbase,+pdpe1gb,+rdrand,+f16c,+osxsave,+dca,+pcid,+pdcm,+xtpr,+tm2,+est,+smx,+vmx,+ds_cpl,+monitor,+dtes64,+pbe,+tm,+ht,+ss,+acpi,+ds,+vme -m 2048 -realtime mlock=off -smp 2,sockets=2,cores=12,threads=2 -uuid 5ad433c9-e490-42f3-b365-c30d756fbd70 -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/hch_test.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime -no-shutdown -global PIIX4_PM.disable_s3=1 -global PIIX4_PM.disable_s4=0 -device ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x5.0x7 -device ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x5 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x6 -drive file=/opt/cvm/hch_test/hch_test.inst,if=none,id=drive-virtio-disk0,format=qcow2,cache=writeback -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x7,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -drive file=/opt/data/hugedisk/hch_test/hch_test_share.add,if=none,id=drive-virtio-disk1,format=qcow2,cache=writeback -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x8,drive=drive-virtio-disk1,id=virtio-disk1 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev spicevmc,id=charchannel0,name=vdagent -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.spice.0 -chardev socket,id=charchannel1,path=/var/lib/libvirt/qemu/hch_test.agent,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel1,id=channel1,name=org.qemu.guest_agent.0 -device usb-tablet,id=input0 -spice port=5930,addr=0.0.0.0,disable-ticketing,seamless-migration=on -device qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,bus=pci.0,addr=0x2 -device intel-hda,id=sound0,bus=pci.0,addr=0x4 -device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -readconfig /etc/qemu/ich9-ehci-uhci.cfg -chardev spicevmc,name=usbredir,id=usbredirchardev1 -device usb-redir,chardev=usbredirchardev1,id=usbredirdev1,bus=ehci.0 -chardev spicevmc,name=usbredir,id=usbredirchardev2 -device usb-redir,chardev=usbredirchardev2,id=usbredirdev2,bus=ehci.0 -chardev spicevmc,name=usbredir,id=usbredirchardev3 -device usb-redir,chardev=usbredirchardev3,id=usbredirdev3,bus=ehci.0 -monitor stdio

 

If someone has tried this suboption, please let me know your conclusion.