1PPS Statistical Data

Enhanced PTP User Guide (UG1602)

Document ID
UG1602
Release Date
2022-10-18
Revision
1.0 English

1PPS statistical counters and error data is available from the following files:

/sys/class/net/eth<N>/device/pps_stats/<filename>

where <filename> is one of the files listed in the following table.

Two sets of data are provided in the form of 1PPS offsets (min, max, mean and last) and 1PPS periods (min, max, mean and last). All measurements are in nanoseconds.

Table 1. PPS Statistics
File Description
pps_off_min Minimum offset value.
pps_off_max Maximum offset value.
pps_off_mean Average offset value observed over the last 8 values.
pps_off_last Most recent offset value.
pps_per_min Minimum 1PPS period.
pps_per_max Maximum 1PPS period.
pps_per_mean Average 1PPS period observed over the last 8 periods.
pps_per_last Most recent 1PPS period.
pps_oflow

Too many 1PPS values received. Operation is suspended until the next sfptpd enable.

This can occur when a cable is connected or as the result of a bad signal or noise on the 1PPS input.

Re-start the sfptpd processes.

pps_bad

Very bad 1PPS period seen. The 1PPS period measured is too long to be a pulse per second i.e. period > 1 second.

Check the 1PPS input is connected to a genuine 1PPS output.