.. _ug_matter_device_optimizing_memory:

Optimizing memory usage in Matter applications
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.. contents::
   :local:
   :depth: 2

You can use different approaches to optimizing the memory usage of your Matter application, both on the |NCS| side and in the Matter SDK.

Reducing memory usage on the |NCS| side
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See the :ref:`app_memory` guide for information about how to reduce memory usage for the |NCS| generally and for specific subsystems in particular, including Bluetooth® LE, Matter, and Thread.

.. _ug_matter_device_optimizing_memory_logs:

Cutting off log regions for Matter SDK modules
**********************************************

The Matter SDK, included in the |NCS| as one of the submodule repositories using a `dedicated Matter fork`_, provides a custom mechanism for optimizing memory usage in a Matter application.
This solution defines a series of logging modules, each of which is a logical section of code that is a source of log messages and can include one or more files.
For the complete list of modules, see the Matter SDK's `LogModule enumeration`_.

You can reduce the memory usage of each of these modules in the following ways:

* Define a custom logging level for each module by setting one of the `Matter SDK logging levels <Matter SDK's Logging header_>`_ (Error, Progress, Detail, or Automation) in :file:`src/chip_project_config.h`,  located in your application's directory.
  For example, the following snippet shows the Bluetooth LE module set to logging at the `Detail` level:

  .. code-block:: c

     CHIP_CONFIG_LOG_MODULE_Ble_DETAIL 1

* Turn off logging for any of the modules by setting its respective enabler to ``0`` in the Matter SDK's `LogModule enumeration`_.
  For example, the following snippet shows the Bluetooth LE module cut off from logging its entries:

  .. code-block:: c

     CHIP_CONFIG_LOG_MODULE_Ble 0

Enabling Link Time Optimization (LTO)
*************************************

You can reduce the memory usage of your Matter application by enabling Link Time Optimization (LTO).

LTO is an advanced compilation technique that performs optimization across all compiled units of an application at the link stage, rather than within each unit separately.

To enable LTO, set the :kconfig:option:`CONFIG_LTO` and :kconfig:option:`CONFIG_ISR_TABLES_LOCAL_DECLARATION` Kconfig options to ``y``.

.. note::
   Support for Link Time Optimization is experimental.