Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx> writes: > On Tue, 17 Jan 2017 16:27:17 +0100 > Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> wrote: > >> 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(-) >> > > It would be good to update Documentation files to describe any configuration needed. This is just a PTP device, not any different for other PTP devices so users will be reading their NTP server docs to figure out how to add a PTP reference clock. Or do you have any particular idea where to put an example? -- Vitaly _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
