Bug 1643983 - RFE: support for extended PTP_SYS_OFFSET ioctl in chrony [NEEDINFO]
Summary: RFE: support for extended PTP_SYS_OFFSET ioctl in chrony
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: chrony
Version: 7.6
Hardware: Unspecified
OS: Unspecified
Target Milestone: rc
: ---
Assignee: Miroslav Lichvar
QA Contact: qe-baseos-daemons
Depends On:
Blocks: 1643962
TreeView+ depends on / blocked
Reported: 2018-10-29 16:43 UTC by Miroslav Lichvar
Modified: 2019-02-07 13:38 UTC (History)
4 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
: 1677218 (view as bug list)
Last Closed: 2018-12-19 14:00:33 UTC
Target Upstream Version:
atragler: needinfo? (mkolaja)

Attachments (Terms of Use)

Description Miroslav Lichvar 2018-10-29 16:43:31 UTC
Description of problem:
A new ioctl is needed to enable a more accurate synchronization of the system clock with HW timestamping (bug #1643974). When available, the ioctl needs to be supported by chrony.

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

How reproducible:

Steps to Reproduce:
1. run chronyd as an NTP client with HW timestamping and look for hwclock messages in the debug output:
    chronyd -d -d "server $LOCAL_NTPSERVER minpoll 2 maxpoll 2" \
       'hwtimestamp *' |& grep 'hwclock.*err='

Actual results:
2018-10-20T19:19:44Z hwclock.c:191:(HCL_AccumulateSample) HW clock samples=16 offset=-1.859570e-08 freq=2.936241e-05 raw_freq=3.643518e-05 err=1.193500e-06 ref_diff=7.251244e+03

It depends on the NIC, PCIe slot, and other things, but usually the reported error is about 0.7-2.5 microseconds.

Expected results:
Reported error smaller than 0.5 microsecond at least for some supported NICs.

Comment 3 Miroslav Lichvar 2018-11-27 14:23:08 UTC
The upstream code now supports the new ioctl.

Comment 6 Red Hat Bugzilla Rules Engine 2018-12-19 14:00:33 UTC
Product Management has reviewed and declined this request.
You may appeal this decision by reopening this request.

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