zephyr

History

Ulf Magnusson 984bfae831 global: Remove leading/trailing blank lines in files Remove leading/trailing blank lines in .c, .h, .py, .rst, .yml, and .yaml files. Will avoid failures with the new CI test in https://github.com/zephyrproject-rtos/ci-tools/pull/112, though it only checks changed files. Move the 'target-notes' target in boards/xtensa/odroid_go/doc/index.rst to get rid of the trailing blank line there. It was probably misplaced. Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>		2019-12-11 19:17:27 +01:00
..
src
arm.conf
CMakeLists.txt
common.conf
mt.conf
no-mt.conf
no-preempt.conf
no-timers.conf	kernel: Crank up default tick rate	2019-07-02 22:52:29 -04:00
README.rst	global: Remove leading/trailing blank lines in files	2019-12-11 19:17:27 +01:00
sample.yaml	yaml: Remove redundant document separators	2019-06-19 10:40:10 +02:00
x86.conf

README.rst

.. _minimal_sample:

Minimal sample
##############

Overview
********

This sample defines An empty ``main()`` and a set of minimal configurations
that provide tests for the smallest ROM sizes possible with the Zephyr kernel.

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
*******************************

In order to compare ROM sizes with different minimal configurations, the
following combinations are suggested:

* Reel board (Arm 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: