zephyr

History

Torsten Rasmussen 1cccc8a8fe cmake: increase minimal required version to 3.20.0 Move to CMake 3.20.0. At the Toolchain WG it was decided to move to CMake 3.20.0. The main reason for increasing CMake version is better toolchain support. Better toolchain support is added in the following CMake versions: - armclang, CMake 3.15 - Intel oneAPI, CMake 3.20 - IAR, CMake 3.15 and 3.20 Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>		2021-08-20 09:47:34 +02:00
..
src
arm.conf
CMakeLists.txt	cmake: increase minimal required version to 3.20.0	2021-08-20 09:47:34 +02:00
common.conf	power: standarize PM Kconfigs and cleanup	2020-12-09 15:18:29 -05:00
mt.conf
no-mt.conf	samples: basic/minimal: disable memory pool when MT=n	2020-09-19 05:49:13 -04:00
no-preempt.conf
no-timers.conf
README.rst
sample.yaml
x86.conf

README.rst

.. _minimal_sample:

Minimal footprint
#################

Overview
********

This sample provides an empty ``main()`` and various configuration files that
can be used to measure Zephyr's minimal ROM footprint in different
configurations.

The following configuration files are available:

* :file:`mt.conf`: Enable multithreading
* :file:`no-mt.conf`: Disable multithreading
* :file:`no-preempt.conf`: Disable preemption
* :file:`no-timers.conf`: Disable timers
* :file:`arm.conf`: Arm-specific disabling of features

Building and measuring ROM size
*******************************

The following combinations are suggested for comparing ROM sizes in different
configurations. They all target the :ref:`reel_board` (Arm Aarch32 architecture).

* Multithreading enabled

  * Reference ROM size: 7-8KB

  .. zephyr-app-commands::
     :zephyr-app: samples/basic/minimal
     :host-os: unix
     :board: reel_board
     :build-dir: reel_board/mt/
     :conf: "common.conf mt.conf arm.conf"
     :goals: rom_report
     :compact:

* Multithreading enabled, no preemption

  * Reference ROM size: 7-8KB

  .. zephyr-app-commands::
     :zephyr-app: samples/basic/minimal
     :host-os: unix
     :board: reel_board
     :build-dir: reel_board/mt-no-preempt/
     :conf: "common.conf mt.conf no-preempt.conf arm.conf"
     :goals: rom_report
     :compact:

* Multithreading enabled, no preemption, timers disabled

  * Reference ROM size: 3-4KB

  .. zephyr-app-commands::
     :zephyr-app: samples/basic/minimal
     :host-os: unix
     :board: reel_board
     :build-dir: reel_board/mt-no-preempt-no-timers/
     :conf: "common.conf mt.conf no-preempt.conf no-timers.conf arm.conf"
     :goals: rom_report
     :compact:

* Multithreading disabled, timers enabled

  * Reference ROM size: 4-5KB

  .. zephyr-app-commands::
     :zephyr-app: samples/basic/minimal
     :host-os: unix
     :board: reel_board
     :build-dir: reel_board/no-mt/
     :conf: "common.conf no-mt.conf arm.conf"
     :goals: rom_report
     :compact:

* Multithreading disabled, timers disabled

  * Reference ROM size: 2-3KB

  .. zephyr-app-commands::
     :zephyr-app: samples/basic/minimal
     :host-os: unix
     :board: reel_board
     :build-dir: reel_board/no-mt-no-timers/
     :conf: "common.conf no-mt.conf no-timers.conf arm.conf"
     :goals: rom_report
     :compact: