Input formats

Formats are detected automatically; -f/--format overrides detection.

--format	Source	Offset used	Extra columns
loopstats	ntpd/NTPsec clock discipline	offset	frequency, jitter, wander, time constant
peerstats	ntpd/NTPsec per peer (sys.peer chosen by default)	offset	delay, dispersion, jitter
rawstats	ntpd/NTPsec on-wire timestamps	recomputed from T1–T4	delay
chrony-tracking	chrony tracking.log	offset (negated)	frequency, skew, offset sd, root delay/dispersion
chrony-measurements	chrony measurements.log per source	θ	delay, dispersion, root delay/dispersion
chrony-statistics	chrony statistics.log	estimated offset (negated)	std dev, skew
chrony-refclocks	chrony refclocks.log (GNSS/PPS)	cooked offset	raw error, dispersion, PPS flag
linuxptp	ptp4l, phc2sys, ts2phc (stdout, syslog, journald)	master/phc offset (negated, ns → s)	path delay, frequency, servo state
pcap	pcap/pcapng captures of NTP (v3/v4/v5) and PTP (v2/v2.1, UDP or Ethernet; see PTP)	NTP: from server T2/T3 and capture times; PTP: master vs capture clock	delay, stratum, version; PTP: path/link delay, one-way delays, correction
csv	generic unix_time,offset[,…], ntpstats monitor output	offset column	any other columns
stable32-phase	Stable32 data file (phase in s; optional MJD timetags; not auto-detected)	chosen column (default last)	—
stable32-freq	Stable32 data file (fractional frequency; zeros are gaps; not auto-detected)	integrated to phase	—
w32tm	Windows w32tm /stripchart /dataonly text or /rdtsc CSV	NtpOffset (server − local)	delay
prometheus	saved Prometheus query_range JSON (ntpstats prom), e.g. ntpd-rs, chrony_exporter	metric value (use --negate for local − reference metrics)	labels in meta
bounds	ClockBound output or earliest,latest[,unix_time,status] CSV	window centre − local	bound (half-width), synchronized
profile:NAME / profile:FILE.toml	instrument exports described by a TOML profile (Sources)	value column (TE negated)	chosen columns
cggtts	CGGTTS V2E GNSS time-transfer files (BIPM); line checksums verified	REFSYS (REF − GNSS time) averaged per epoch	satellites, spread; ntpstats cv for two sites
rinex-clock	RINEX clock (IGS .clk, gzip accepted)	clock bias per receiver/satellite	sigma
circular-t	BIPM Circular T section 1 (issues may be concatenated)	UTC − UTC(k) per laboratory	uncertainties in meta
ripe-atlas	RIPE Atlas NTP results (API JSON)	offset (negated: Atlas logs local − server)	rtt, stratum, root delay/dispersion
ntppool	NTP Pool monitor score log CSV	offset per monitor	rtt, score, step
gsoc2012	the 2012 prototype's estimators.log	offset	—

ntpstats convert writes any of these as a Stable32 file or plain CSV (see Stable32, TimeLab, allantools).

The research and laboratory formats are described with worked examples in Research data. Gzipped files (.gz) are read directly.

Sign convention

Every series uses reference − local (the ntpd convention: positive means the local clock is behind). Parsers normalise on import, following each implementation's documentation:

Source	Logged as	ntpstats
ntpd/NTPsec logs, ntpq rv	reference − local	kept
chrony measurements (θ), refclocks (cooked), chronyc tracking "System time"	reference − local	kept
chrony tracking, statistics, chronyc sourcestats	local − reference	negated
linuxptp master offset/offset	local − reference	negated
pcap	computed	reference − capture host
RIPE Atlas	local − server	negated
Circular T	UTC − UTC(k)	kept (UTC is the reference)

Enabling the logs

• chrony: log tracking measurements statistics refclocks and logdir /var/log/chrony.
• ntpd/NTPsec: statsdir /var/log/ntpstats/, statistics loopstats peerstats rawstats, filegen peerstats file peerstats type day enable (likewise for the others).
• linuxptp: run with -m, or collect journalctl -u ptp4l -o short-iso-precise, which maps the monotonic stamps to UTC.
• captures: tcpdump -i eth0 -j adapter_unsynced --time-stamp-precision=nano -w ntp.pcap udp port 123.

Large files

The numeric columns of loopstats, peerstats and chrony logs are parsed with numpy's C tokenizer (about 1–3 s per million lines). Irregular files fall back to a tolerant per-line parser that reports skipped lines in meta["skipped_lines"].