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 v4: - Rebase to the current char-misc-next tree [K. Y.] - Drop const qualifier from ptp_hyperv_info [kbuild test robot] - Implement .getcrosststamp() callback [Radim Krcmar] Vitaly Kuznetsov (3): hv_util: switch to using timespec64 hv: export current Hyper-V clocksource hv_utils: implement Hyper-V PTP source arch/x86/hyperv/hv_init.c | 13 ++- arch/x86/include/asm/mshyperv.h | 3 + drivers/hv/hv_util.c | 183 +++++++++++++++++++++++++++++++++------- 3 files changed, 166 insertions(+), 33 deletions(-) -- 2.9.3 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
