performance: 0.929
peripherals: 0.895
graphic: 0.885
device: 0.676
semantic: 0.637
virtual: 0.596
ppc: 0.372
mistranslation: 0.322
register: 0.320
risc-v: 0.302
boot: 0.296
VMM: 0.287
permissions: 0.269
debug: 0.229
vnc: 0.217
PID: 0.205
arm: 0.195
architecture: 0.182
user-level: 0.138
KVM: 0.131
kernel: 0.115
hypervisor: 0.109
TCG: 0.101
assembly: 0.101
socket: 0.100
network: 0.060
files: 0.053
x86: 0.008
i386: 0.003

High mouse polling rate stutters some applications
Description of problem:
There are couple of instances where moving the mouse would slow down some applications, especially for games

https://www.reddit.com/r/VFIO/comments/ect3sd/having_an_issue_with_my_vm_where_games_stutter/

https://www.reddit.com/r/VFIO/comments/n9hwtg/game_fps_drop_on_mouse_input/

https://www.reddit.com/r/VFIO/comments/ln1uwb/evdev_mouse_passthrough_with_1000hz_mouse_causes/

https://www.reddit.com/r/VFIO/comments/se92rq/looking_for_advice_on_poor_gpu_passthrough/

I myself included, is impacted by this mysterious issue, I'm not pretty sure whether this is related to VFIO or QEMU or both, but I'm definitely sure this is a kind of regression in between since I had no such issue before.
Steps to reproduce:
1. Do a GPU passthrough
2. Get a mouse capable of outputting high polling rate like 1000Hz, usually they are categorized as gaming mouses
3. Start any 3D applications, including stuff like Unreal Engine 4 Editor or any games
4. See mysterious stuttering
Additional information:
I'm using an AMD Ryzen 7 3700X CPU as the host, but I have made scripts that pins CPU to the VM to get better performance speculatively by putting the threads on the same CCX to minimize memory latency as much as possible. This alleviated some terrible lag, but not by much. (like 11 FPS to 20 FPS if you move your mouse which is still crappy compared to 90+ FPS when static)

I suspect there is something wrong with the USB subsystem.