Reducing mbed rtos footprint to smallest size possible

Questions » Reducing mbed rtos footprint to smallest size possible

5 years, 9 months ago.

Using the Mbed-cli, how can I tell the linker to only include code that is actually used. ie. I wan't to see how small of a footprint I can produce using mbed and the rtos.

thanks

1 Answer

5 years, 9 months ago.

Hello Kevin,

You can take a look at these blog posts:

https://os.mbed.com/blog/entry/Optimizing-memory-usage-in-mbed-OS-52/

https://os.mbed.com/blog/entry/Reducing-memory-usage-by-tuning-RTOS-con/

They offer several steps you can take to optimize your memory usage. Hope this helps!

-Karen, team Mbed

_{If this solved your question, please make sure to click the "Thanks" link below!}

Ok, I think I have followed these threads. It appears that some of the optimizations come from just using a later version of mbed. I'm currently on the latest mbed 5.9. And I created an mbed_app.json file with the following configuration: ``` { "macros": [ "NDEBUG=1" ], "target_overrides": { "*": { "platform.stdio-flush-at-exit": false } } } ```

Here is the before and after results on a simple blink program. ``` +----+-+-++

Module

.text

.data

.bss

+----+-+-++

[fill]	108	0	17
[lib]/c.a	24793	2472	89
[lib]/gcc.a	3112	0	0
[lib]/misc	208	12	28
mbed-os/drivers	192	4	100
mbed-os/features	108	4	88
mbed-os/hal	1707	4	68
mbed-os/platform	2834	264	221
mbed-os/rtos	10394	168	6073
mbed-os/targets	8622	4	744
src/main.o	60	4	28
Subtotals	52138	2936	7456

+----+-+-+~~+ Total Static RAM memory (data + bss): 10392 bytes Total Flash memory (text + data): 55074 bytes~~

+----+-+-++

Module

.text

.data

.bss

+----+-+-++

[fill]	104	0	14
[lib]/c.a	15851	2472	56
[lib]/gcc.a	3112	0	0
[lib]/misc	208	12	28
mbed-os/drivers	136	4	100
mbed-os/features	108	4	88
mbed-os/hal	1406	4	68
mbed-os/platform	1499	8	213
mbed-os/rtos	10017	168	6073
mbed-os/targets	8115	4	744
src/main.o	60	4	28
Subtotals	40616	2680	7412

+----+-+-+~~+ Total Static RAM memory (data + bss): 10092 bytes Total Flash memory (text + data): 43296 bytes ```~~

Should I be able to do better than this?

posted by Kevin McQuown 03 Jul 2018

Have you tried this configuration for the mbed_app.json?

{
    "macros": [
        "NDEBUG=1",
        "OS_TASKCNT=1",
        "OS_IDLESTKSIZE=32",
        "OS_STKSIZE=1",
        "OS_TIMERS=0",
        "OS_FIFOSZ=4",
        "OS_MUTEXCNT=1"
    ],
    "target_overrides": {
        "*": {
            "platform.stdio-flush-at-exit": false
        }
    }
}

posted by Karen Yen 05 Jul 2018

Kevin McQuown

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5 years, 9 months ago.