Flash size constraints

RE: Flash size constraints

ovrebekk — Thu, 04 Nov 2021 14:50:23 GMT

If that is the case the GNU GSL library alone needs more than 400kB of flash...

I asked for some input from the software developers, but they didn't have any good suggestions either. The linker should remove any unused functions automatically, so if it still doesn't fit in flash there isn't much you can do.

The 'simple' solution is to get an nRF52840DK or an nRF5340DK.

Theoretically it is possible to run code directly from the external flash chip on the DK, and I will do some checking internally to see if it is possible to configure a project in the nRF Connect SDK to do this.

Best regards
Torbjørn

RE: Flash size constraints

Ales — Wed, 03 Nov 2021 11:52:26 GMT

[quote userid="2116" url="~/f/nordic-q-a/81179/flash-size-constraints/337236#337236"]You could try to set CONFIG_SIZE_OPTIMIZATIONS in your project configuration, as described here.[/quote]

Thanks for that. Unfortunately this method did not show any effect on size of code in my example.

Here is the output with commented function calls for GNU GSL:

In case I include the library than this output is not present as errors are displayed. In this case I get error "region `FLASH' overflowed by 10800 bytes".

RE: Flash size constraints

ovrebekk — Wed, 03 Nov 2021 10:33:08 GMT

Hi Ales

[quote user="Ales"] As I know -O can have number of possible optimization. -Os is suppose to be optimize for size. Can I include this one? Or is it possible to remove debug information to reduce size?[/quote]

You could try to set CONFIG_SIZE_OPTIMIZATIONS in your project configuration, as described here.

This should ensure that the optimization is set for size.

[quote user="Ales"]Can you please tell me where can I check that?[/quote]

I think the easiest way is to check the build output before you enable the GLS library, and then check it again after.

When you have built a project you should see a report of the total RAM and flash consumption, similar to this:

[9/9] Linking C executable zephyr\zephyr.elf
Memory region         Used Size  Region Size  %age Used
           FLASH:      197400 B         1 MB     18.83%
            SRAM:       46605 B       256 KB     17.78%
        IDT_LIST:          0 GB         2 KB      0.00%

Best regards
Torbjørn

RE: Flash size constraints

Ales — Tue, 02 Nov 2021 09:41:27 GMT

Hi,

first of all thanks for suggestions.

[quote userid="2116" url="~/f/nordic-q-a/81179/flash-size-constraints/336811#336811"]-O is enabled by default, so you don't have to do anything in order to set this parameter. [/quote]

As I know -O can have number of possible optimization. -Os is suppose to be optimize for size. Can I include this one? Or is it possible to remove debug information to reduce size?

[quote userid="2116" url="~/f/nordic-q-a/81179/flash-size-constraints/336811#336811"]I assume you have checked that there are no alternative libraries that could do the job, such as this one, or this one?[/quote]

- (first link) as I know a uC with DSP is needed which nRF52833 does not support.

- (second link) I looked at zscilib but it does not support multiplications on matrices with complex values (only real)

[quote userid="2116" url="~/f/nordic-q-a/81179/flash-size-constraints/336811#336811"]Can you let me know what the flash usage of the GNU GSL library alone is, when you build the code?[/quote]

Can you please tell me where can I check that?

[quote userid="2116" url="~/f/nordic-q-a/81179/flash-size-constraints/336811#336811"]Maybe you can share the .map file with me?[/quote]

devzone.nordicsemi.com/.../1464.zephyr.map

RE: Flash size constraints

ovrebekk — Mon, 01 Nov 2021 09:55:59 GMT

Hi Ales

-O is enabled by default, so you don't have to do anything in order to set this parameter.

I assume you have checked that there are no alternative libraries that could do the job, such as this one, or this one?

Can you let me know what the flash usage of the GNU GSL library alone is, when you build the code?

Maybe you can share the .map file with me?

Best regards
Torbjørn

RE: Flash size constraints

Ales — Thu, 28 Oct 2021 09:08:48 GMT

I noticed that screenshot of GSL functions in zephyr.map was not provided so I add it below.