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Docs/admin-guide/mm/damon/usage: update the ways for getting monitoring results

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The recommended ways for getting DAMON monitoring results are using
tried_regions sysfs directory for partial snapshot of the results, and
DAMON tracepoint for full record of the results.  However, the
tried_regions sysfs directory usage has not sufficiently updated on some
sections of the DAMON usage document.  Update those.

Link: https://lkml.kernel.org/r/20230616191742.87531-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
SeongJae Park 2023-06-16 19:17:42 +00:00 committed by Andrew Morton
parent 67c34f6c6a
commit ff71f26f97
1 changed files with 12 additions and 8 deletions
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20
Documentation/admin-guide/mm/damon/usage.rst
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@ -19,10 +19,7 @@ DAMON provides below interfaces for different users.
features by reading from and writing to special sysfs files. Therefore, features by reading from and writing to special sysfs files. Therefore,
you can write and use your personalized DAMON sysfs wrapper programs that you can write and use your personalized DAMON sysfs wrapper programs that
reads/writes the sysfs files instead of you. The `DAMON user space tool reads/writes the sysfs files instead of you. The `DAMON user space tool
<https://github.com/awslabs/damo>`_ is one example of such programs. Note <https://github.com/awslabs/damo>`_ is one example of such programs.
that this interface provides only simple :ref:`statistics <damos_stats>` for
the monitoring results. For detailed monitoring results, DAMON provides a
:ref:`tracepoint <tracepoint>`.
- *debugfs interface. (DEPRECATED!)* - *debugfs interface. (DEPRECATED!)*
:ref:`This <debugfs_interface>` is almost identical to :ref:`sysfs interface :ref:`This <debugfs_interface>` is almost identical to :ref:`sysfs interface
<sysfs_interface>`. This is deprecated, so users should move to the <sysfs_interface>`. This is deprecated, so users should move to the
@ -421,6 +418,11 @@ The directories will be removed when another special keyword,
``clear_schemes_tried_regions``, is written to the relevant ``clear_schemes_tried_regions``, is written to the relevant
``kdamonds/<N>/state`` file. ``kdamonds/<N>/state`` file.
The expected usage of this directory is investigations of schemes' behaviors,
and query-like efficient data access monitoring results retrievals. For the
latter use case, in particular, users can set the ``action`` as ``stat`` and
set the ``access pattern`` as their interested pattern that they want to query.
tried_regions/<N>/ tried_regions/<N>/
------------------ ------------------
@ -771,10 +773,12 @@ root directory only.
Tracepoint for Monitoring Results Tracepoint for Monitoring Results
================================= =================================
DAMON provides the monitoring results via a tracepoint, Users can get the monitoring results via the :ref:`tried_regions
``damon:damon_aggregated``. While the monitoring is turned on, you could <sysfs_schemes_tried_regions>` or a tracepoint, ``damon:damon_aggregated``.
record the tracepoint events and show results using tracepoint supporting tools While the tried regions directory is useful for getting a snapshot, the
like ``perf``. For example:: tracepoint is useful for getting a full record of the results. While the
monitoring is turned on, you could record the tracepoint events and show
results using tracepoint supporting tools like ``perf``. For example::
# echo on > monitor_on # echo on > monitor_on
# perf record -e damon:damon_aggregated & # perf record -e damon:damon_aggregated &