The Traps of Using Hyper-V Features in KVM Environment
summary
KVM exposes many Hyper‑V features to improve Windows performance but enabling them can hurt real workloads: cloud gaming shows 35,000 IPIs/sec spikes and one‑to‑many APIC sends ~200/sec, and enabling Hyper‑V timers drops high‑end frame rates (proportion with fps >55 drops 10%). Root cause is timer selection: S‑timer (HV STIMER) forces software interrupt injection and raises VM exits. Tested fixes include disable hypervisor CPUID, change Windows timer selection, or patch HV timer handling (disable AUTOEOI, use APIC MSR, optimize interrupt‑induced VMX); prototype patches make S‑timer cost similar to local APIC and restore performance.
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chapters (11)
- 0:00Intro
- 0:36Content
- 1:05Background
- 2:15Workload characteristics of cloud gaming
- 4:33Performance comparison with different config
- 6:08How Windows guest choose system timer
- 7:34Virtualization officiency of different system timers
- 9:30Cause Analysis
- 11:51Solutions
- 14:53Effect of optimization
- 16:20Conclusion
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