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.

[Carles]

Hi there!

Any chance you could give the latest package a try?

https://community.chocolatey.org/packages/dtc-msys2/1.6.1

Not sure how you replace the one that is bundled with NCS, but perhaps you could try 1.6.1 separately to see if it helps?

You can use `choco install dtc-msys2` to install this version.

[Peter Haas]

Hi Carles,

thank you for your reply.

I just had the chance to try the toolchain by manually installing the version of dtc as you suggested.
Copying all the binaries from chocolatey into their respective location in the ncs toolchain works.

However it seems that doesn't fix our problem. 
The build is still taking a very long time and I have to swap networks to shorten that. It does seem to be a bit faster than our initial version (~8 minutes instead of 15m)

Best
Peter