Ubuntu
linux-azure-4.15 package

  1. Eoan (19.10)
  2. Bug #1875467
  3. Comment #0

Comment 0 for bug 1875467

Revision history for this message
Joseph Salisbury (jsalisbury) wrote :

Microsoft would like to request two commits in all releases supported on Azure. These commits benefit SAP workloads.

These requested commits will enable support for Invariant TSC in Linux guest VMs. The invariant TSC means that the TSC continues at a fixed rate regardless of the C-state or frequency of the processor (as long as the processor remains in the ACPI S0 state).

These patches will allow guests to access the HvSyntheticInvariantTscControl MSR and set bit 0 of this synthetic MSR, which then enables the InvariantTSC feature. After setting the synthetic MSR, CPUID will enumerate support for InvariantTSC.

The following two commits enable support:
9e0333ae38ee ("clocksource/drivers/hyper-v: Set TSC clocksource as default w/ InvariantTSC")
dce7cd62754b ("x86/hyperv: Allow guests to enable InvariantTSC")