Zephyr and the Memory Footprint: Difference between revisions

From chriesibaum wiki
Jump to navigation Jump to search
No edit summary
No edit summary
Line 5: Line 5:
{| style="width: 100%;"
{| style="width: 100%;"
| style="width: 50%; vertical-align:top;" |
| style="width: 50%; vertical-align:top;" |
main.c:
''main.c:''
<syntaxhighlight lang="c">
<syntaxhighlight lang="c">
void main (void) {
void main (void) {
Line 17: Line 17:
</syntaxhighlight>
</syntaxhighlight>
| style="width: 50%; vertical-align:top;"|
| style="width: 50%; vertical-align:top;"|
prj.conf:
''prj.conf:''
<syntaxhighlight lang="c">
<syntaxhighlight lang="c">
# disable all peripherals
# disable all peripherals
Line 28: Line 28:
CONFIG_BOOT_BANNER=n
CONFIG_BOOT_BANNER=n


#disable all debug and log messages
# disable all debug and log messages
CONFIG_DEBUG=n
CONFIG_DEBUG=n
# enable compiler size opt. (this is the default anyway)
CONFIG_SIZE_OPTIMIZATIONS=y
</syntaxhighlight>
</syntaxhighlight>
|}
|}

Revision as of 13:05, 26 January 2021

Do you want to use Zephyr RTOS on a Microcontroller with only a few bytes of Flash? Let's try it!

On the Optimizing for Footprint doc site you will find some hints how to reduce the memory footprint. Ok let's do it. I compiled the following application by using this configs:

main.c: 

void main (void) {
    uint32_t i = 0;
    
    // run the loop for ever
    while (true) {
        i++;
    }
}

prj.conf: 

# disable all peripherals
CONFIG_GPIO=n
CONFIG_SERIAL=n
CONFIG_SPI=n
CONFIG_I2C=n

# disable the boot banner
CONFIG_BOOT_BANNER=n

# disable all debug and log messages
CONFIG_DEBUG=n

# enable compiler size opt. (this is the default anyway)
CONFIG_SIZE_OPTIMIZATIONS=y


With this application and settings I could reduce the total application to 6872 bytes: 

west build -p auto -b <board name>

Memory region         Used Size  Region Size  %age Used
           FLASH:        6872 B        16 KB     41.94%
            SRAM:        1232 B         2 KB     60.16%
        IDT_LIST:          56 B         2 KB      2.73%

Ok, this is just the compiled kernel to have an idea how much flash it needs. You can analyze the memory usage from the rom/ram-report. By using west build -t rom_report you will get a really nice report of the flash coverage. The same procedure for a ram usage report: west build -t ram_report For more details have a look at the Zephyr Docs: Optimization Tools).


But how much does a small hello world application need, for example?

Retrieved from "https://wiki.chriesibaum.dev/index.php?title=Zephyr_and_the_Memory_Footprint&oldid=32"