Compiling too slow

[WillieVisagie]

Description of defect

Compiling the project are simply too slow.  It's literally a show stopper.  What can be done about it?  This is such an awesome platform but the compile time is killing it.

Target(s) affected by this defect ?

All targets

Toolchain(s) (name and version) displaying this defect ?

ARM GCC

What version of Mbed-os are you using (tag or sha) ?

latest

What version(s) of tools are you using. List all that apply (E.g. mbed-cli)

mbed-cli, GCC arm toolchain 10 2021.10, etc.

How is this defect reproduced ?

Build your project from scratch

[0xc0170]

you are using mbed build command? What examples/tests are you testing with and what are the times you get ?

[0xc0170]

Can you try to set MBED_BUILD_TIMESTAMP via command line:

-DMBED_BUILD_TIMESTAMP=100 ? And enable ccache - this should make it much faster (see #8359)

[WillieVisagie]

Hi

Yes - I'm using mbed compile --profile=debug.

Do you mean to pass these two arguments (-DMBED_BUILD_TIMESTAMP=100 and ccache) on the command line when calling mbed compile?

[WillieVisagie]

Can anyone answer my question, please?

[llawrence12]

Personally I use the .mbedignore file to remove any unneeded/unwanted things from mbed-os and that significantly drops my compile time (once in the root of the project it must be named ".mbedignore"). Maybe there's a better way to do it but I don't know/care about it since this works for me. I also don't use anything newer than os 6.8.0 with CLI 1 so things may have changed in newer versions

Here is the one I use, you can change it to include/exclude what you like
mbedignore.txt

Also after it has been compiled once it should only recompile small changes, unless you edit something like the mbed_app.json, after which it will start from scratch again. This is also all just personal experience, your mileage may vary

[WillieVisagie]

Great idea. I will definitely do that.

Another idea is to use mbed-tools, or CLI version 2. But then again, I have such trouble with the CMakeLists.txt files, because every time you add the mbed-os library, it gets recompiled. So I guess I just need to learn cmake and its CMakeLists.txt files.

[ladislas]

This problem is well known and due to the use of interface in cmake instead of static or object libs.

see #13981 (comment) and subsequent comments

there was some work done to fix that, but the changes are huge and development has slowed down.

there is a work in progress from @multiplemonomials you can find here: https://github.com/multiplemonomials/mbed-os/tree/mbed-ce-build-system-refactor

and also ongoing discussions about making a community fork of mbed-os to fix this kind of issues early and then back port them if possible to the main mbed-os repo.

[rvasquez6089]

Thats pretty normal.
Windows is the worst offender. If i need to use windows, I install Ubuntu 20.04 in WSL and compile my project in the WSL filesystem on Ubuntu. Its about 5 times faster than windows.
If I need super fast build times, I go to native Linux. its about 7 times faster than windows good luck!