Hi all. I was wondering what are your usual build times for KMP projects? We have around 270 shared ...

# multiplatform

[RadimJanda]

Hi all.
I was wondering what are your usual build times for KMP projects?
We have around 270 shared modules for SwiftUi app and the release build time currently takes around 2 hours. (debug build is much faster, like 10-20min)
We use cocoapods, the modules vary from little ones (with 2 classes to bigger ones 100+-classes).
The step that takes almost all time is
./gradlew -p shared kmmsharedKmm:syncFramework -Pkotlin.native.cocoapods.platform=iphonesimulator -Pkotlin.native.cocoapods.archs=arm64 -Pkotlin.native.cocoapods.configuration=Release
I wonder if such build times are normal, or if there is something we can do to speed it up.

[tapchicoma]

Have you seen this: https://kotlinlang.org/docs/native-improving-compilation-time.html?

[tapchicoma]

also in 2.2.20 release we finally will add support for https://kotlinlang.org/docs/gradle-compilation-and-caches.html#build-reports for Native part. It would be nice if you could shared them to us once you will update you project to this release

[RadimJanda]

Build reports for native part sounds cool. Definitely will look into it once possible. I will look into the page for improving compilation times as well. Do you think this build times are far too high than expected?

[tapchicoma]

Hard to tell without build metrics. This is a release build where much more is optimized. Plus we don't know amount of code you have in the project

[RadimJanda]

@tapchicoma is it possible to try this kotlin native build reports in 2.2.20 beta?

[tapchicoma]

Beta1 has a problem on the Native compiler side which is fixed in Beta2, so please try in the next beta

[RadimJanda]

Hello I tried in Beta2 and I see following times

Task ':kmm:sharedKMM:linkPodReleaseFrameworkIosSimulatorArm64' finished in 17,699.94 s
Time metrics:
  Total Gradle task time: 17,699.94 s
  Spent time before task action: 0.11 s
  Run compilation in Gradle worker: 5,139.18 s
    Run native in process: 5,139.18 s
      Run entry point: 5,139.17 s
    Compiler initialization time: 0.17 s
    Compiler code analysis: 0.35 s
    Compiler translation to IR: 10.54 s
    Compiler IR lowering: 20.38 s
    Compiler backend: 5,107.70 s
Size metrics:
  Start time of task action: 2025-07-31T21:27:49

Is this the kotlin native build report or is there something more somewhere? At the moment I see almost all time is taken by Compiler backend

[RadimJanda]

@tapchicoma

[tapchicoma]

yes, this is the report. You could try to enable JSON format and share it with us

[RadimJanda]

Thank you @tapchicoma, here is JSON build report. I had to do some basic obfuscation of module names as this is public chat, let me know if it works.

obfuscated_output.json

[tapchicoma]

@sergey.bogolepov could someone from the team take a look into it? thank you color

[sergey.bogolepov]

Hey @RadimJanda! Release compilation times are known problem and we are working on them. Is there any chance that you can share your project with us (e.g. under NDA)? 🙏 This way we will be able to find hotspots that will help your project.

[RadimJanda]

Thank you for your willingness @sergey.bogolepov I think it should be possible under NDA. I will discuss it with project mangers and will let you know.

[RadimJanda]

Hello @sergey.bogolepov, so it was approved to share the project under NDA. Do you have some email where we could contact you and resolve all these formalities?

[RadimJanda]

@tapchicoma do you have some info about this possibility to share codebase under NDA in order for compilation build times improvements as was offered by sergey? Thank you

[sergey.bogolepov]

FTR: We will continue our discussion in DM