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Feature #12527

closed

export hrtime params for pvclock impls

Added by Patrick Mooney about 2 years ago. Updated about 2 years ago.

Status:
Closed
Priority:
Normal
Category:
kernel
Start date:
Due date:
% Done:

100%

Estimated time:
Difficulty:
Medium
Tags:
bhyve
Gerrit CR:

Description

Upstreaming OS-7014:

The pvclock implementations described in OS-6949 and OS-7102 require knowledge of the TSC scale/shift parameters in order to present their expected interface to the guest. For the near-term, it probably makes sense to do so via a more expressive tsc_gethrtime_* variant, leaving us room in the future to refine that os-internal interface.

I tested this with the pending changes for OS-7102 (its only consumer for the time being) on node with synced TSCs (westmere) and one with skewed TSCs (IvyB, where we reset TSCs during boot due to errata). On both nodes, a Linux guest running in KVM is able to establish a stable NTP fix using the kvm-clock data as its clocksource.

Actions #1

Updated by Electric Monk about 2 years ago

  • Status changed from In Progress to Closed
  • % Done changed from 0 to 100

git commit fc3fd29d04595458a24c7d90eb46ce039660a44f

commit  fc3fd29d04595458a24c7d90eb46ce039660a44f
Author: Patrick Mooney <pmooney@pfmooney.com>
Date:   2020-04-19T19:54:52.000Z

    12527 export hrtime params for pvclock impls
    Reviewed by: John Levon <john.levon@joyent.com>
    Reviewed by: Robert Mustacchi <rm@joyent.com>
    Reviewed by: Mike Gerdts <mike.gerdts@joyent.com>
    Reviewed by: Andy Fiddaman <andy@omniosce.org>
    Reviewed by: Toomas Soome <tsoome@me.com>
    Approved by: Dan McDonald <danmcd@joyent.com>

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