Can PTP be configured in Slew mode in Red Hat Enterprise Linux ?

Solution In Progress - Updated -

Environment

  • Red Hat Enterprise Linux 6 and 7

Issue

  • Can PTP be configured in Slew mode in Red Hat Enterprise Linux ?

Resolution

add -x option to /etc/sysconfig/phc2sys or kernel_leap 0 to /etc/ptp4l.conf when Sofware timestamping is used

Root Cause

From the man pages of phc2sys:

-x When a leap second is announced, don't apply it in the kernel by stepping the clock, but let the servo correct the one-second offset slowly by changing the clock frequency (unless the -S
option is used).

From the man pages of ptp4l

kernel_leap
When a leap second is announced, let the kernel apply it by stepping the clock instead of correcting the one-second offset with servo, which would correct the one-second offset slowly by changing the clock frequency (unless the step_threshold option is set to correct such offset by stepping). Relevant only with software time stamping. The default is 1 (enabled).

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