|BT(5)||File Formats Manual||BT(5)|
BT — Bug Tracing
BT language, also known as BPFtrace
syntax, describes how to format and display information gathered from
specified probe events.
Events are generated by the dynamic tracer dt(4) when an enabled probe is triggered. They are periodically collected by btrace(8), which formats them using the corresponding action. If a recorded event doesn't match the optional filter it will be silently ignored.
BT source file contains at least
one probe clause associated with an
The list of available probes may vary from system to system and can be queried with btrace(8).
The special probes
END may be used to manipulate states before the
first event is recorded and after the last. They cannot be combined with any
Define under which condition an event should be recorded when its related probe is executed. An empty filter means record all events.
Variable names available in filters:
An action is a sequence of statements that are evaluated for each event recorded by the associated probe.
Variable names with special meaning:
lhist(value, min, max, step)
BPFtrace reference guide, https://github.com/iovisor/bpftrace/blob/master/docs/reference_guide.md.
|April 21, 2021||OpenBSD-current|