.. _nanos6-verbose-instrumentation:

Verbose instrumentation
-----------------------

.. index::
    triple: Nanos6; verbose; instrumentation

To enable verbose logging, run the application with the ``version.instrument`` configuration variable set to ``verbose``.

By default it generates a lot of information.
This is controlled by the ``instrument.verbose.areas`` configuration variable, which can contain a list of areas.
The areas are the following:

**AddTask**
  Task creation.

**Blocking**
  Blocking and unblocking within a task through calls to the blocking API.

**ComputePlaceManagement**
  Starting and stopping compute places (CPUs, GPUs, etc).

**DependenciesByAccess**
  Dependencies by their accesses.

**DependenciesByAccessLinks**
  Dependencies by the links between the accesses to the same data.

**DependenciesByGroup**
  Dependencies by groups of tasks that determine common predecessors and common successors.

**LeaderThread**
  Execution of the leader thread.

**LoggingMessages**
  Additional logging messages.

**TaskExecution**
  Task execution.

**TaskStatus**
  Task status transitions.

**TaskWait**
   Entering and exiting taskwaits.

**ThreadManagement**
  Thread creation, activation and suspension.

**UserMutex**
  User-side mutexes (critical).

The case is ignored, and the ``all`` keyword enables all of them.
Additionally, an area can have the ``!`` prepended to it to disable it.
For instance, ``areas = [ "AddTask", "TaskExecution" , "TaskWait" ]`` is a good starting point.

The default value is::

     [instrument]
         [instrument.verbose]
             areas = ["all", "!ComputePlaceManagement", "!DependenciesByAccess", "!DependenciesByAccessLinks",
                 "!DependenciesByGroup", "!LeaderThread", "!TaskStatus", "!ThreadManagement"]

By default, events are recorded with their timestamp and ordered accordingly.
This can be disabled by setting the ``instrument.verbose.timestamps`` configuration variable to ``false``.

The output is emitted by default to standard error, but it can be sent to a file by specifying it through the ``instrument.verbose.output_file`` option.
Also the ``instrument.verbose.dump_only_on_exit`` can be set to ``true`` to delay the output to the end of the program to avoid getting it mixed with the output of the program.