Optimizing my Windows VM for Photoshop
Posted on - February 23, 2025 by Andy Cinquin
VMFedoraWindows
I optimized my Windows VM to get a more responsive Photoshop. Here are the key changes I made to the configuration.
CPU Configuration
Before
<vcpu placement="static">8</vcpu>
<cpu mode="host-passthrough" check="none" migratable="on"/>
The CPU was in shared mode - all cores were competing between Linux and Windows.
After
<vcpu placement="static">6</vcpu>
<cputune>
<vcpupin vcpu='0' cpuset='1'/>
<vcpupin vcpu='1' cpuset='2'/>
<vcpupin vcpu='2' cpuset='3'/>
<vcpupin vcpu='3' cpuset='4'/>
<vcpupin vcpu='4' cpuset='5'/>
<vcpupin vcpu='5' cpuset='6'/>
<emulatorpin cpuset='0,7'/>
</cputune>
<cpu mode="host-passthrough" check="none" migratable="off">
<topology sockets="1" cores="6" threads="1"/>
<cache mode="passthrough"/>
</cpu>
Now, each virtual core is assigned to a specific physical core. Cores 0 and 7 are reserved for Linux.
Memory Management
Before
<memoryBacking>
<source type="memfd"/>
<access mode="shared"/>
</memoryBacking>
Basic memory configuration without specific optimizations.
After
<memoryBacking>
<hugepages/>
<nosharepages/>
<source type="memfd"/>
<access mode="shared"/>
</memoryBacking>
Added hugepages for better memory management and reduced latency.
Disk Configuration
Before
<disk type="file" device="disk">
<driver name="qemu" type="qcow2" discard="unmap"/>
<source file="/var/lib/libvirt/images/win11-tiny.qcow2"/>
<target dev="sda" bus="sata"/>
</disk>
Default disk configuration without I/O optimizations.
After
<disk type="file" device="disk">
<driver name="qemu" type="qcow2" discard="unmap" cache="none" io="native"/>
<source file="/var/lib/libvirt/images/win11-tiny.qcow2"/>
<target dev="sda" bus="sata"/>
<iotune>
<total_bytes_sec>4294967296</total_bytes_sec>
<read_iops_sec>6000</read_iops_sec>
<write_iops_sec>6000</write_iops_sec>
</iotune>
</disk>
Disk access optimization with native cache and balanced I/O limits.
Network Interface
Before
<interface type="network">
<model type="e1000e"/>
</interface>
Intel e1000e network card emulation (more compatible but less performant).
After
<interface type="network">
<model type="virtio"/>
</interface>
Using virtio driver for optimal network performance.
Additional Configuration
You also need to enable hugepages on the Linux host system:
sudo bash -c "echo 'vm.nr_hugepages = 6144' >> /etc/sysctl.d/40-hugepages.conf"
sudo sysctl -p /etc/sysctl.d/40-hugepages.conf
These modifications result in:
- A more responsive Windows interface
- Better performance in Photoshop
- Better coexistence between Linux and Windows
- Faster disk access
To apply these changes, you need to:
- Edit the XML file with
sudo virsh edit vm_name - Stop the VM
- Apply system changes (hugepages)
- Restart the VM
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