does ksp have performance logging like kapt? https://kotlinlang.org/docs/kapt.html#measuring-the-number-of-files-generated-with-annotation-processors

No, feel free to open an issue as feature request on Github.

https://blog.jetbrains.com/kotlin/2022/06/introducing-kotlin-build-reports/ seems like it does what I want

Task ':library:kspKotlin' finished in 0.66 s
Compilation log for task ':library:kspKotlin':
  Compiler perf stats:
          ANALYZE     454 ms
Time metrics:
  GRADLE_TASK_ACTION: 0.02 s
  GRADLE_TASK: 0.66 s
    CLEAR_OUTPUT: 0.00 s
    CONNECT_TO_DAEMON: 0.01 s
    CLEAR_JAR_CACHE: 0.00 s
    NON_INCREMENTAL_COMPILATION_DAEMON: 0.50 s

Build attributes:
  REBUILD_REASON: IC_IS_NOT_ENABLED

I opened a related issue a while back https://github.com/google/ksp/issues/374 That could be updated in light of the new kotlin build report feature

Thanks for the pointer.