We're currently using Serialization (1.3.2, but tr...

# serialization

[cb]

We're currently using Serialization (1.3.2, but trying 1.3.3 and 1.4 now) for serializing some very simple objects into JSON (they're basically Android navigation holders). We use these classes a lot. They're used for all navigation calls in our Android app, and get serialized at each navigate(), therefore performance is important. Most of these Args classes we have are @Serializable object MyScreenArgs: ArgsInterface, and some are data classes if they contain some inner values.

We've seen that creating a serializer() for the object classes is extremely slow:

7,137ns   benchmarkDataClassContentViewArgsToBundle
69,204ns  benchmarkObjectContentViewArgsToBundle
5,301ns   benchmarkDataClassBundleToContentViewArgs
67,981ns  benchmarkObjectBundleToContentViewArgs

(tests using AndroidX Microbenchmark on a Google Pixel 1)

It doesn't matter if we use the reflection or non-reflection versions of serializer(), they're both very similar in terms of time. In fact, the generated serializer is usually slightly slower to retrieve for some reason.

I've profiled our tests, and 90% of the time is spent retrieving the serializer(), the conversion to/from JSON is around 3ms for all benchmarks. Anyone know why the object serializer could be so slow?

[mbonnin]

Any chance you can share the benchmarks? I'd be curious to investigate this

[mbonnin]

My impression based on that issue was that reflection would dominate the parsing time and that non-reflection would be quite faster

[cb]

Benchmarks + more results: https://github.com/chrisbanes/kotlin-serialization-object-perf

[cb]

Raised an issue as there's definitely seems like there is something here: https://github.com/Kotlin/kotlinx.serialization/issues/2003