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.