Toolchain very slow on Windows machines

[Peter Haas]

Dear Nordic Team,

we are using the adafruit_feather_nrf52840 and nrf52840dk for our prototypes and recently the toolchain around nrf and zephyr has become a problem.

Build times (especially compilation of the device tree according to logs) became very long such that one reload of our cmake project takes up to 15 minutes.

It had worked in reasonable time previously, at some point the toolchain slowed down on 2 individual machines.
This has happened on 2 different machines with 3 different versions of zephyr and the nrf toolchain (v2.6.0, v2.6.1, v2.7.0).

I tested using standalone zephyr for the build which doesn't seem to work trivially, however it does build an image in less than 10 seconds.
Also on a Linux machine I have available, the build times are much shorter.

Is anybody aware of any windows specific problems or problems with dtc.exe that may cause this?

Is there some cache we directory or temporal files we may have missed to clean?

We have been investigating for some time now as it really slows down our development iterations severely.

[Simonr]

Hi

What kind of project are you building here that takes so long? On a slow computer that has to build a large project (like the Matter stack for example) it might take this long, but still 15 minutes sounds like the upper limit of what should be possible. Something may be off with your NCS installation, so the first thing to try would be to uninstall and reinstall the nRF Connect SDK and toolchain on your end. I assume this only happens when doing a pristine build, and that it goes faster once the application is built once, please correct me if I'm wrong.

Best regards,

Simon

[Alex-Sony]

Hi Simon,

Thank you for your reply. Our project is fairly simple, no external dependencies, only Nordic + Zephyr  + Our code.

We also know that it is not our code the problem since we were able to compile it fairly fast before and tried using a very old commit that was stable and we still get slow compilation times. We also tried using samples from Nordic and the samples also take the same 15 minutes to compile.

What would you recommend to do in order to isolate the possible cause of the issue?

Thank you.

Alex