latency.awk

A quick way to visualize latency from access logs. The assumption is that the access log has the duration in µs as its final field, that is %D in Apache HTTPd. (https://httpd.apache.org/docs/2.4/mod/mod_log_config.html).

Also, we rely on the date looking something similar to [11/Nov/2023:00:00:00 +0000].

Prerequisites

• GNU awk (gawk).
• Gnuplot (gnuplot).

Invocation

latency.awk access.log

Output is a heat map, by default written to stdout as Sixel escape codes. A commonly used terminal, iTerm2.app supports this out of the box.

Example

Improvement Points

• Use a proper logarithmic scale for bucketing latencies.
• Make it easier to use a different output format.
• etc.