package magic-trace

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Intended for use like so:

let min_dur = Magic_trace.Min_duration.of_ns 3_000

let my_fun a b c =
  Magic_trace.mark_start ();
  (* ... *)
  if Magic_trace.Min_duration.over min_dur then Magic_trace.take_snapshot ()

which allows capturing only unusually long executions without adding the ~10us breakpoint overhead on every run while magic-trace is attached.

See also the -duration-thresh flag for use in combination with this or instead of it if you can tolerate a 10us pause on every call.

type t
val of_ns : int -> t

This involves using and forcing Time_stamp_counter.calibrator so should probably be done only once at the top level as opposed to every time.

val over : t -> bool

Returns true if the time since mark_start is over the threshold