memtrace#

A streaming client for OCaml's Memprof, which generates compact traces of a program's memory use.

Installation#

Install with opam:

opam install nox-memtrace

If opam cannot find the package, it may not yet be released in the public opam-repository. Add the overlay repository, then install it:

opam repo add samoht https://tangled.org/gazagnaire.org/opam-overlay.git
opam update
opam install nox-memtrace

Usage#

To profile the memory use of a program, start by putting this line somewhere at the program startup:

Memtrace.trace_if_requested ()

If the --memtrace FILE command-line flag is passed or the MEMTRACE environment variable is set, tracing begins to the specified file. (If neither is present, nothing happens.)

The ~context parameter is optional and can be set to any string that helps identify the trace file.

Memtrace.trace_if_requested ~context:"v1.2.3" ()

For Cmdliner-based CLIs, use Memtrace.term to integrate the flag into your command line parser.

If the program daemonises, the call to trace_if_requested should occur after the program forks, to ensure the right process is traced.

The resulting trace files can be analysed with some simple command-line tools in bin/, but the recommended interface is the memtrace viewer, which lives in:

$ MEMTRACE=trace.ctf ./my-service
$ jane/app/memtrace_viewer trace.ctf