Bug 1117702 - SHM refclock doesn't support nanosecond resolution
Summary: SHM refclock doesn't support nanosecond resolution
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: ntp
Version: 7.0
Hardware: Unspecified
OS: Unspecified
Target Milestone: rc
: ---
Assignee: Miroslav Lichvar
QA Contact: Jakub Prokes
Depends On:
Blocks: 1191019 1205796 1095800 1117704
TreeView+ depends on / blocked
Reported: 2014-07-09 08:41 UTC by Miroslav Lichvar
Modified: 2015-11-19 08:37 UTC (History)
7 users (show)

Fixed In Version: ntp-4.2.6p5-20.el7
Doc Type: Enhancement
Doc Text:
Support for nanosecond resolution has been added to the SHM reference clock. Prior to this update, when a Precision Time Protocol (PTP) hardware clock was used as a time source to synchronize the system clock (for example, with the timemaster service from the linuxptp package), the accuracy of the synchronization was limited due to the microsecond resolution of the SHM protocol. The nanosecond extension in the SHM protocol now allows sub-microsecond synchronization of the system clock.
Clone Of:
: 1117704 (view as bug list)
Last Closed: 2015-11-19 08:37:19 UTC
Target Upstream Version:

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Network Time Protocol 1232 0 None None None Never
Red Hat Product Errata RHSA-2015:2231 0 normal SHIPPED_LIVE Moderate: ntp security, bug fix, and enhancement update 2015-11-19 09:03:04 UTC

Description Miroslav Lichvar 2014-07-09 08:41:06 UTC
Description of problem:
The SHM refclock in ntpd is limited to microsecond resolution. In 4.2.7 development a nanosecond extension was added to the protocol. This can be useful to improve accuracy of the synchronization with PTP clocks and phc2sys from linuxptp.


Version-Release number of selected component (if applicable):

Comment 9 errata-xmlrpc 2015-11-19 08:37:19 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.


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