我正在将一些安装移至在 Linux 主机上的 KVM VM 中运行的 Windows Server Datacenter Core 2019。
我的第一台 Windows VM 在空闲时每秒有超过 32000 次 VM 退出，其中一半是 MSR 写入，另一半是 HLT 指令。相比之下，空闲的 Linux VM 每秒大约有 20 次退出。
由于虚拟机有 16 个线程，我在这里得到了一些不错的整数：每个 CPU 设置一个计时器，每秒精确进入睡眠状态 1000 次，所以我怀疑（可能是错的）有一个 1kHz 计时器每一个CPU。这会导致所有 CPU 的负载增加约 1-5%，我希望减少这一数字。
Windows 上是否始终存在该计时器？如果存在，是否有设置可以调整它？如果不是，是否有工具可以找出 Windows 认为需要此类计时器的原因？
虚拟硬件是 virtio-net 和 viostor，一个 EHCI USB 控制器，带有一个用于鼠标接口的 HID 平板电脑、PS/2 键盘和鼠标以及一个 QXL 显卡。我只公开了 HPET 和 Hyper-V 计时器，但如果我还提供 RTC 和 PIT，似乎没有什么区别：
<domain type='kvm'>
<name>test-win2019</name>
<uuid>56f23fbd-9173-4f8e-b63a-59b7eb667fc0</uuid>
<memory unit='KiB'>16777216</memory>
<currentMemory unit='KiB'>16777216</currentMemory>
<memoryBacking>
<hugepages/>
</memoryBacking>
<vcpu placement='static' cpuset='8-15,24-31'>16</vcpu>
<numatune>
<memory mode='strict' nodeset='1'/>
</numatune>
<os>
<type arch='x86_64' machine='pc-q35-2.8'>hvm</type>
<loader readonly='yes' secure='no' type='pflash'>/usr/share/OVMF/OVMF_CODE.fd</loader>
<nvram template='/usr/share/OVMF/OVMF_VARS.fd'>/var/lib/libvirt/nvram/test-win2019_VARS.fd</nvram>
</os>
<features>
<acpi/>
<apic/>
<hyperv>
<relaxed state='on'/>
<vapic state='on'/>
<spinlocks state='on' retries='8191'/>
</hyperv>
</features>
<cpu mode='custom' match='exact' check='full'>
<model fallback='forbid'>Skylake-Client-IBRS</model>
<vendor>Intel</vendor>
<topology sockets='1' cores='8' threads='2'/>
<feature policy='require' name='ss'/>
<feature policy='require' name='hypervisor'/>
<feature policy='require' name='tsc_adjust'/>
<feature policy='require' name='umip'/>
<feature policy='require' name='md-clear'/>
<feature policy='require' name='ssbd'/>
<feature policy='require' name='pdpe1gb'/>
<feature policy='disable' name='mpx'/>
<feature policy='disable' name='xsavec'/>
<feature policy='disable' name='xgetbv1'/>
<numa>
<cell id='0' cpus='0-15' memory='16777216' unit='KiB'/>
</numa>
</cpu>
<clock offset='localtime'>
<timer name='hpet' present='yes'/>
<timer name='hypervclock' present='yes'/>
</clock>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>restart</on_crash>
<pm>
<suspend-to-mem enabled='no'/>
<suspend-to-disk enabled='no'/>
</pm>
<devices>
<emulator>/usr/bin/kvm</emulator>
<disk type='block' device='disk'>
<driver name='qemu' type='raw' cache='none' io='native'/>
<source dev='/dev/darine/test-win2019'/>
<backingStore/>
<target dev='vda' bus='virtio'/>
<boot order='1'/>
<alias name='virtio-disk0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
</disk>
<disk type='file' device='cdrom'>
<driver name='qemu' type='raw'/>
<source file='/srv/WindowsServer2019.iso'/>
<backingStore/>
<target dev='sda' bus='sata'/>
<readonly/>
<boot order='2'/>
<alias name='sata0-0-0'/>
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</disk>
<disk type='file' device='cdrom'>
<driver name='qemu' type='raw'/>
<source file='/srv/virtio-win_amd64.iso'/>
<backingStore/>
<target dev='sdb' bus='sata'/>
<readonly/>
<alias name='sata0-0-1'/>
<address type='drive' controller='0' bus='0' target='0' unit='1'/>
</disk>
<controller type='usb' index='0' model='ich9-ehci1'>
<alias name='usb'/>
<address type='pci' domain='0x0000' bus='0x02' slot='0x00' function='0x0'/>
</controller>
<controller type='pci' index='0' model='pcie-root'>
<alias name='pcie.0'/>
</controller>
<controller type='pci' index='1' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='1' port='0x8'/>
<alias name='pci.1'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0' multifunction='on'/>
</controller>
<controller type='pci' index='2' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='2' port='0x9'/>
<alias name='pci.2'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
</controller>
<controller type='pci' index='3' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='3' port='0xa'/>
<alias name='pci.3'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
</controller>
<controller type='sata' index='0'>
<alias name='ide'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x1f' function='0x2'/>
</controller>
<interface type='network'>
<mac address='52:54:00:1e:46:45'/>
<source network='default' bridge='virbr0'/>
<target dev='vnet3'/>
<model type='virtio'/>
<alias name='net0'/>
<address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
</interface>
<input type='tablet' bus='usb'>
<alias name='input0'/>
<address type='usb' bus='0' port='1'/>
</input>
<input type='mouse' bus='ps2'>
<alias name='input1'/>
</input>
<input type='keyboard' bus='ps2'>
<alias name='input2'/>
</input>
<graphics type='vnc' port='5909' autoport='no' listen='127.0.0.1'>
<listen type='address' address='127.0.0.1'/>
</graphics>
<video>
<model type='qxl' ram='65536' vram='16384' vgamem='16384' heads='1' primary='yes'/>
<alias name='video0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
</video>
<memballoon model='none'/>
</devices>
<seclabel type='dynamic' model='apparmor' relabel='yes'>
<label>libvirt-56f23fbd-9173-4f8e-b63a-59b7eb667fc0</label>
<imagelabel>libvirt-56f23fbd-9173-4f8e-b63a-59b7eb667fc0</imagelabel>
</seclabel>
<seclabel type='dynamic' model='dac' relabel='yes'>
<label>+64055:+64055</label>
<imagelabel>+64055:+64055</imagelabel>
</seclabel>
</domain>
答案1
您需要在标签下启用synic和。换句话说：stimerhyperv
<hyperv>
<synic state='on'/>
<stimer state='on'/>
</hyperv>
以上内容应是标签下已有的其他参数的补充hyperv。