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ping-monitor — record ping over time and flag spikes

A small bash tool that pings a target on an interval, colour-flags latency spikes, and prints a summary (min/avg/max, p50/p95/p99, spike count, loss) on Ctrl-C. A full log is written to ~/ping-monitor-YYYYmmdd-HHMMSS.log.

It exists because the most useful first step in diagnosing "my Wi-Fi gaming lags in bursts" is to ping your own gateway for a while: a clean baseline with periodic huge spikes points at the local wireless medium, not the ISP or the game server. See WiFi latency spikes.

Install

Deployed automatically by chezmoi as ~/.dotfiles/bin/ping-monitor. Pure bash, no dependencies; works on macOS and Linux (it picks the right ping timeout flag per platform).

Usage

ping-monitor [TARGET] [SPIKE_MS] [INTERVAL_S]
ping-monitor -g | --gateway [SPIKE_MS] [INTERVAL_S]

# Examples
ping-monitor                 # default gateway, flag >100ms
ping-monitor -g 10           # gateway, flag anything >10ms (local-link test)
ping-monitor 8.8.8.8 150 0.5 # upstream host, >150ms, every 0.5s
pinggw                       # alias for `ping-monitor --gateway`
  • TARGET — host/IP. Omit (or use -g/--gateway) to auto-detect the default gateway.
  • SPIKE_MS — latency at/above which a sample is flagged (default 100). For a gateway/local-link test, drop this to ~10.
  • INTERVAL_S — seconds between pings (default 1).

Output is colour-coded: dim = normal, yellow = approaching the threshold, red = spike or loss.

Reading the result

min/avg/max     : 1.3 / 44.0 / 408.2 ms
p50/p95/p99     : 2.0 / 282.2 / 345.4 ms
spikes          : 66  (>10ms)

A low p50 with a high p95/p99 is the signature of bursty spikes (the case this tool is built to catch) — the link is fine most of the time but stalls periodically. A uniformly high baseline instead points at distance / routing / an overloaded upstream.

See also