GH Action for FLASH size diff

[alexcekay]

Solved Problem

Increase awareness of the impact of a code change on FLASH size. Allow developers to see exactly how much and where their change will increase FLASH usage.

Solution

• In case of a PR:
  • Compile the base revision
  • Compile the current revision of the branch
  • Diff the flash usage using bloaty
• In case of a commit on main:
  • Compile the previous main revision
  • Compile the current main revision
  • Diff the flash usage using bloaty

Alternatives / Future

This is an initial working version that includes the following two boards:

• px4_fmu-v5x
• px4_fmu-v6x

If we want, we can easily add more boards in the future.

This version compiles 2 times for each board (1 compile before / 1 compile after) to create the diff. With two boards this results in 4 compiles, which is fast and only creates a small overhead. If we add many more boards, we should reuse the artifacts created by other jobs. However, this will increase the complexity of the code as an external script will need collect the artifacts from the base and current revisions and unpack them.

[github-actions]

FLASH Analysis

px4_fmu-v5x

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +0.0%      +8  +0.0%      +8    .text
  -0.0%      -8  [ = ]       0    [Unmapped]
  [ = ]       0  +0.0%      +8    TOTAL

px4_fmu-v6x

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +0.0%      +8  +0.0%      +8    .text
  -0.0%      -8  [ = ]       0    [Unmapped]
  [ = ]       0  +0.0%      +8    TOTAL

[PetervdPerk-NXP]

The bloaty build in px4io/px4-dev-nuttx-focal tends to segfault time to time.
Could we, use a more updated container?

Also maybe include ram as well and only trigger on a big delta.

[alexcekay]

Hi @PetervdPerk-NXP,
I closed this PR and moved it to this one #23868.
Regarding your comment:

• Do you have an example of the bloaty build causing a segfault. It did not happen yet on any of the tests of the action on my fork. With an example of the segfault I can diff which version is used there and in my action.
• Regarding RAM: The static RAM part is included in bloaty via .bss and .data. This is however only a rather small part in PX4 due to most of the RAM usage being caused by mallocs. We plan to add a dynamic execution for measuring RAM (heap) usage