Performance with KSP2 degraded by nearly 50%

[mcarleio]

Hi!

I am migrating Konvert to KSP2 and am using kotlin-compile-testing 0.7.0 for running the tests.

The performance of executing gradle test with KSP1 was around 12-13 minutes (avg) in GitHub Actions. After migration, it now takes 23min! Nearly twice as long!

I verified that locally and can confirm: executing the tests with KSP2 takes much longer on my machine as well: 6 min (KSP1) vs 9-10 min (KSP2)!
I then checked, if the duration of the processor itself degraded by logging the processor execution time and then calculating the average. With KSP1 the average processor run was around 28ms vs 32ms with KSP2. As there are executed around 1000 runs during testing Konvert, that would only explain 5 seconds difference. Which is far less than multiple minutes.

So I wonder where those minutes are lost. Maybe you have an idea?

Feel free to see for yourself:

• KSP2: Code / Build
• KSP1: Code / Build

Nevertheless, thanks for your work, I really appreciate it 👍

[jisungbin]

It's probably related to KSP#2282.