Hi there. I’m at a loss and I need help. This has been an ongoing issue for months. Perhaps linked to R4.3 since I started using it since the alpha. I have two computers
1 Desktop with a Ryzen 9000 series
1 Laptop with Arrow Lake
On both computers I went with BTRFS and (I believe) 4KB sector size because I liked the idea of better performance, advanced features, and want to be able to do interesting things with combining and shifting SSDs and HDDs. I never got that far, I’m just trying to get things working on a single NVME drive on each system.
Things seem to work well until I add in GPU passthrough. On the desktop, I get extremely slow performance when the NVIDIA 3080 is attached. I also experienced this slowness when trying a Fedora and Ubuntu HVM. The hard drive response time varies wildly often bouncing between 25ms and over 1000ms and HDD disk usage in task manager spikes often even with lite usage. And it is only on the HVM that this lag and freeze happens. Dom0 is happy to let me do things while the HVM is frozen in time until it decides to move again. It most recently happened consistently when I tried to download large files (hence my inclination it may have to do with the file system). I’m also a bit unhappy the VM disks show as HDD (ATA) when ATA has long since been replaced by AHCI in the industry. Nor do I see memory or CPU or GPU spikes in the time around the freeze.
For the laptop, getting usb passthrough was a disaster requiring many hours and a custom patch developed by other forum members to bypass Intel’s stupid common usb root (despite different pcie usb devices). Dom0 and everything else freezes up when sys-usb is started until sys-usb is finished loading all the devices. I used M.2 oculink to PCIE adapter and a RX6600 and things seemed to be well passing that through to a Windows HVM. However, during video calls my audio would slingshot and trying to use a webcam would result in my video going multicolored (not for me or OBS but for the recipient). I also experienced brief lag spikes but not so much that it wasn’t usable.
So the point is, I have no idea what I am doing wrong. I’m happy to provide additional info, I’m just at a complete loss.
I was going to completely wipe my desktop and try to reinstall with ext4 instead of BTRFS and then restore backups (besides Dom0) but I figured I should ask for help first.
I previously used a windows HVM on R4.2 and it wasn’t bare-metal performance but it was usable, even for gaming, and didn’t have lag spikes and Windows freezing on me. I tried using fstrim and defrag on the desktop and that didn’t help. Should I go ahead and do a reinstall on my desktop without BTRFS? Or is there something I should try first?
I have modified libvirt xml. I have changed
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vendor_id on
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vpindex on
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runtime on
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synic on
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stimer on
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reset on
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frequencies on
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kvm hidden on
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ioapic driver kvm
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cpu mode host-passthrough
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hypervisor disable
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invtsc require
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svm disable
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vmx disable