Optimizing for Footprint
Stack Sizes
Stack sizes of various system threads are specified generously to allow for usage in different scenarios on as many supported platforms as possible. You should start the optimization process by reviewing all stack sizes and adjusting them for your application:
CONFIG_ISR_STACK_SIZESet to 2048 by default
CONFIG_MAIN_STACK_SIZESet to 1024 by default
CONFIG_IDLE_STACK_SIZESet to 320 by default
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZESet to 1024 by default
CONFIG_PRIVILEGED_STACK_SIZESet to 1024 by default, depends on userspace feature.
Unused Peripherals
Some peripherals are enabled by default. You can disable unused peripherals in your project configuration, for example:
CONFIG_GPIO=n
CONFIG_SPI=n
Various Debug/Informational Options
The following options are enabled by default to provide more information about the running application and to provide means for debugging and error handling:
CONFIG_BOOT_BANNERThis option can be disabled to save a few bytes.
CONFIG_DEBUGThis option can be disabled for production builds
MPU/MMU Support
Depending on your application and platform needs, you can disable MPU/MMU support to gain some memory and improve performance. Consider the consequences of this configuration choice though, because you’ll lose advanced stack checking and support.