Module Unmark.Measurement.Probe

module Probe: sig .. end

Probe construction and manipulation.

Counters

type counter

Individual measured quantity.

val ctr : ?unit:string -> ?desc:string -> string -> counter

ctr ?unit ?desc name is a description of counter named name.

unit is the counter's measurement unit. When absent, a simple count is assumed.

desc is a human-readable description.

val name : counter -> string

val desc : counter -> string

val unit : counter -> string option

val pp_ctr : counter Unmark.fmt

pp_ctr ppf c pretty-prints c on ppf.

type probe

Probes perform the actual measurements, producing a set of counters.

val probe : counters:counter list ->
       (float array -> int -> unit) -> probe

probe ~counters f is a probe p that collects counters counters using the function f.

f is invoked as f arr i and must write the values of individual counters into arr.(i) .. arr.(i + length counters - 1).

counters declares both the number and the order of counters that p measures.

val nothing : probe

nothing is the probe that measures nothing.

val (++) : probe ->
       probe -> probe

p1 ++ p2 the probe that measures both the counters in p1 and p2.

val counters : probe -> counter list

counters p are the counters that p measures.

val pp : probe Unmark.fmt

pp ppf p pretty-prints p on ppf.

val gc_q_stat : probe

A probe for the GC subsystem, using Gc.quick_stat.

Counters:

min - words allocated on the minor heap (Gc.minor_words);
prom - words promoted to the major heap (Gc.promoted_words);
maj - words allocated directly on the major heap (Gc.major_words - Gc.promoted_words);
gc_min - number of minor collections (Gc.minor_collections); and
gc_maj - number of major collections (Gc.major_collections).

val gc_counters : probe

A probe for the GC subsystem, using Gc.counters.

val rdtsc : probe

Reads the timestamp counter, using x86 RDTSC instruction.

Produces the counter tsc.