Messages in this thread | | | From | Vitaly Kuznetsov <> | Subject | [PATCH v3 0/2] hv_util: adjust system time smoothly | Date | Tue, 17 Jan 2017 16:27:17 +0100 |
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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 v2: - Implement Hyper-V PTP device instead of doint in-kernel time sync.
Changes since "[PATCH RFC] hv_utils: implement Hyper-V PTP source": - Richard Cochran: implement .adjfreq, .adjtime, .settime64 returning -EOPNOTSUPP. - Olaf Hering: change IS_ERR->IS_ERR_OR_NULL as CONFIG_PTP_1588_CLOCK can be disabled. - Thomas Gleixner: formatting fixes, comments added.
Vitaly Kuznetsov (2): hv_util: switch to using timespec64 hv_utils: implement Hyper-V PTP source
drivers/hv/hv_util.c | 142 +++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 116 insertions(+), 26 deletions(-)
-- 2.9.3
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