Description of problem: flag 'hv_vapic' can't improve Windows 7 guest's performance evidently Version-Release number of selected component (if applicable): How reproducible: 2/2 Steps to Reproduce: 1. boot guest with command [1] without flag 'hv_vapic' 2. Using the IOmeter tool observer the storage performance a.download the tool inside the guest http://sourceforge.net/projects/iometer/files/iometer-stable/1.1.0/iometer-1.1.0-win64.x86_64-bin.zip/download b.Open the IOmeter and do configuration "Disk Target" ==> "D: "" "Access Specifications" ==> "4KiB 100% Read;" "Test Setup" ==> "30 Minutes" c. Start Test 3.Shutdown the guest. Then boot the same guest again with command "-cpu Skylake-Client-IBRS,+kvm_pv_unhalt,hv_vapic". Repeat the step 2 Actual results: storage performance without any flag PROCESSOR,CPU 1 ==> 90.14% IOPS ==> 137927.50 storage performance with the flag "hv_vapic" PROCESSOR,CPU ==> 82.42% IOPS ==> 130868.31 Expected results: flag 'hv_vapic' can improve Windows 7 guest's performance evidently Additional info: /usr/libexec/qemu-kvm -name win7 -M q35 -enable-kvm \ -cpu Skylake-Client-IBRS \ -monitor stdio \ -nodefaults -rtc base=utc \ -m 4G \ -smp 2,sockets=1,cores=2,threads=2,maxcpus=4 \ -qmp tcp:0:4444,server,nowait \ -object secret,id=sec0,data=redhat \ -blockdev node-name=back_image,driver=file,cache.direct=on,cache.no-flush=off,filename=/home/1-win7/win7.luks,aio=threads \ -blockdev node-name=drive-virtio-disk0,driver=luks,cache.direct=on,cache.no-flush=off,file=back_image,key-secret=sec0 \ -device pcie-root-port,id=root0,slot=0 \ -device virtio-blk-pci,drive=drive-virtio-disk0,id=disk0,bus=root0 \ -blockdev node-name=back_image1,driver=file,cache.direct=on,cache.no-flush=off,filename=/home/1-win7/win7-disk.qcow2,aio=threads \ -blockdev node-name=drive-virtio-disk1,driver=qcow2,cache.direct=on,cache.no-flush=off,file=back_image1 \ -device pcie-root-port,id=root2,slot=2 \ -device virtio-blk-pci,drive=drive-virtio-disk1,id=disk1,bus=root2 \ -device pcie-root-port,id=root1,slot=1 \ -device virtio-net-pci,mac=70:5a:0f:38:cd:a4,id=idhRa7sf,vectors=4,netdev=idNIlYmb,bus=root1 -netdev tap,id=idNIlYmb,vhost=on \ -drive id=drive_cd1,if=none,snapshot=off,aio=threads,cache=none,media=cdrom,file=/home/iso/windows/virtio-win-prewhql-0.1-172.iso \ -device ide-cd,id=cd1,drive=drive_cd1,bus=ide.0,unit=0 \ -device ich9-usb-uhci6 \ -device usb-tablet,id=mouse \ -device qxl-vga,id=video1 \ -spice port=5903,disable-ticketing \ -device virtio-serial-pci,id=virtio-serial1 \ -chardev spicevmc,id=charchannel0,name=vdagent \ -device virtserialport,bus=virtio-serial1.0,nr=3,chardev=charchannel0,id=channel0,name=com.redhat.spice.0 \
Test Environments Host: kernel-4.18.0-119.el8.x86_64 qemu-4.1.0-rc1 seabios-bin-1.11.1-4.module+el8.1.0+3531+2918145b.noarch Guest: en_windows_7_ultimate_with_sp1_x64_dvd_u_677332.iso