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    Subject[PATCH v4 0/2] hv_util: adjust system time smoothly
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    With TimeSync version 4 protocol support we started updating system time
    continuously through the whole lifetime of Hyper-V guests. Every 5 seconds
    there is a time sample from the host which triggers do_settimeofday[64]().
    While the time from the host is very accurate such adjustments may cause
    issues:
    - Time is jumping forward and backward, some applications may misbehave.
    - In case an NTP server runs in parallel and uses something else for time
    sync (network, PTP,...) system time will never converge.
    - Systemd starts annoying you by printing "Time has been changed" every 5
    seconds to the system log.

    Instead of doing in-kernel time adjustments offload the work to an
    NTP client by exposing TimeSync messages as a PTP device. Users may now
    decide what they want to use as a source.

    Changes since v3:
    - Minor style changes [Stephen Hemminger]
    - Added a comment explaining why we don't fail the driver registration
    when ptp_clock_register() fails [Thomas Gleixner]
    - Add Thomas' A-b to PATCH1

    Vitaly Kuznetsov (2):
    hv_util: switch to using timespec64
    hv_utils: implement Hyper-V PTP source

    drivers/hv/hv_util.c | 146 ++++++++++++++++++++++++++++++++++++++++++---------
    1 file changed, 120 insertions(+), 26 deletions(-)

    --
    2.9.3

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