IssueTracker

Thank you for the report.

When the compile time fluctuate this much, it could be caused by the JVM getting close to max memory and the GC portion of the compile time goes up.

As you have a dump, then you can easily reproduce the same build with different settings using tools/compiledump.py. tools/compiledump.py use the gsutil to download the compiler from our build repository. If you don't have that tool, you can get the compiler with curl -O https://storage.googleapis.com/r8-releases/raw/8.3.35/r8lib.jar (for version 8.3.35), and then add --r8-jar r8lib.jar to the commands below. The commands all pass -da which disables assertions. tools/compiledump.py enabled assertions by default, but that makes compilation even slower, and AGP does not do that.

1. Are you seeing the same loooooong compile time locally when running tools/compiledump.py -da -d <dump>?
2. If so you can try to pass the -verbose:gc to the JVM when running, should be doable like this: tools/compiledump.py -da -J=-verbose:gc -d <dump>. Seems like the output is not streamed so you will have to wait for the command to finish.
3. If that shows massive GC, you can try different heap sizes, to see if changing that affects compilation time, e.g. like this: tools/compiledump.py -da --xmx 8G -J=-verbose:gc -d <dump>

If possible you can share the dump privately with sgjesse@google.com and ricow@google.com, then we can also try to see if we can reproduce the issue.

The CI calculates the values for xmx etc... depending on the current machine. The one use here should have enough resources to build the app without issues.

This is what it calculated for this particular machine, which has 32 GB of RAM (properties written inside of ~/.gradle/gradle.proprties).

org.gradle.jvmargs = -Dfile.encoding=UTF-8 -XX:+HeapDumpOnOutOfMemoryError -XX:MaxMetaspaceSize=1g -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -Xmx16854m -Xms16854m
kotlin.daemon.jvmargs = -Dfile.encoding=UTF-8 -XX:+HeapDumpOnOutOfMemoryError -XX:MaxMetaspaceSize=1g -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -Xmx7223m -Xms7223m

I let gradle and kotlin use 75% of the total memory, 70% of that is for gradle, the remaining 30% for kotlin.

I once ran the build with -Dcom.android.tools.r8.printmemory, but the CI stopped after it reached its limit of 3.5 hours. This is what I saw:

R8 is running with total memory:17683185664
R8 is running with free memory:14891000672
R8 is running with max memory:17683185664

I have multiple zips inside the directory of dumpinputtodirectory and compiledump.py takes roughly 10 minutes to process the largest one. Even when I pass --Xmx 8G.

I'll try to play a bit with the memory settings and see if that's the problem, as you suspect. I could also try to run R8 in a separate process as mentioned here.

I'll try to can figure this out and I'll see if I can share the dump in case I can't find anything.

Thank you for the prompt response.

I think you were right about this being a memory issue. I added the following and even after multiple tries, the minification step took 10 minutes consistently.

android {
    execution {
        profiles {
            standard {
                r8 {
                    jvmOptions += ["-Xms2048m", "-Xmx8192m", "-XX:+HeapDumpOnOutOfMemoryError"]
                    runInSeparateProcess = true
                }
            }
        }

        defaultProfile = "standard"
    }
}

I don't know if something has changed, I thought 16GB were enough for gradle and R8 combined, considering that a build without R8 requires less than 8GB.

Anyway, thank you for the pointer, I think you can close this now.

Thank you for the feedback, good to hear that you found a solution.

I had already written what is below, so sharing this anyway.

Each dump has the file build.properties in the root. The one which has tool=R8 is the R8 invocation.

One other tip is to unzip the dump unzip dump.zip -d /tmp/dump, and add --temp /tmp/dump to running tools/compiledump.py. Then the command printed by tools/compiledump.py (shuld be like the one below) can be easily re-run with JVM different options without foing through the tools/compiledump.py wrapper.

/usr/local/google/home/sgjesse/prj/r8/ws1/third_party/openjdk/jdk-11/linux/bin/javac /usr/local/google/home/sgjesse/prj/r8/ws1/src/main/java/com/android/tools/r8/utils/CompileDumpCompatR8.java /usr/local/google/home/sgjesse/prj/r8/ws1/src/main/java/com/android/tools/r8/utils/CompileDumpBase.java -d /tmp/dump -cp r8lib.jar
Running: /usr/local/google/home/sgjesse/prj/r8/ws1/third_party/openjdk/jdk-11/linux/bin/java -verbose:gc -cp /tmp/dump:r8lib.jar com.android.tools.r8.utils.CompileDumpCompatR8 --release /tmp/dump/program.jar --output /tmp/dump/out.jar --lib /tmp/dump/library.jar --classpath /tmp/dump/classpath.jar --desugared-lib /tmp/dump/desugared-library.json --desugared-lib-pg-conf-output /tmp/dump/desugared-library-keep-rules.config --pg-conf /tmp/dump/proguard.config --pg-map-output /tmp/dump/out.jar.map --min-api 23 --enable-missing-library-api-modeling

Just ran into this in the Now in Android app: https://github.com/android/nowinandroid/issues/1595

I got the same problem. But it happens only in object, it doesn't happen if RouteThatIsNeverNavigatedTo (in my case: RouteThatIsNavigatedOnlyByDeepLink) is data class. The workaround for now is to annotate it with @Keep. I hope it will be fixed soon.

predumably because of a combination of type erasure of generics and R8 minification

Not sure if the problem is in Jetpack Navigation or Kotlin Serialization. If you call crash(MyObject::class), it will also crash. But it does not crash if you invoke crash(MyClass::class).

The crash function:

@OptIn(InternalSerializationApi::class)
fun crash(cls: KClass<*>) {
    println(cls.serializer())
}

@Serializable object MyObject

@Serializable class MyClass

I saw that NavDestinationBuilder also uses this internal serialization API.

Hello, any updates for this?

Navigation library does not expose kotlinx serialization as an api dependency.

But thanks for pointing out that this issue is fixed in 1.8.0 - I tested the repro in the original post and Feature1Graph is indeed now kept in minified release builds without requiring @Keep annotation.

Since this was an issue in the kotlinx library itself, type safety users will have to bump their kotlinx serialization to 1.8.0 to get this fix.