test-simplified-lxr

name	test-simplified-lxr
description	Test simplified LXR GC under lxr-x/simplified branch

Test simplified LXR GC

Ensure the correct branches are checked out

• mmtk-core: lxr-x/simplified branch (based on tag v0.32.0)
• mmtk-openjdk: lxr-x/jdk21-simplified branch (based on tag v0.32.0-jdk-21)
• openjdk: jdk-21.0.9+3-mmtk-lxr

The above branches contain the simplified version of the LXR GC, which has removed some performance optimizations and other non-essential features to make it easier for upstreaming.

You can generate git diff for both mmtk-core and mmtk-openjdk to understand the changes in the two branches.

Run tests

Please run the following command to test the correctness of the simplified LXR GC:

mmtk-jdk run --gc LXR -n 5 --heap 30M --bench xalan --build --no-weak-refs --no-class-unloading

Note that:

• Weak/soft/phantom/finalizable reference processing should be disabled with --no-weak-refs
• class unloading should be disable with --no-class-unloading
• The mmtk-jdk command sets RUST_LOG=warning by default if it is missing, to avoid verbose logging output.
• Testing one benchmark is not enough. You should try the following benchmark and heap size combinations:
  • lusearch: 40M
  • fop: 80M (without weak refs, 80M is the minimium heap size)
  • xalan: 30M
  • cassandra: 250M
  • pmd: 400M
• You only need to build once before running multiple benchmarks, if no code is edited between runs.
• Verify both debug builds and release builds (with --release)
• Always add -n 5 to run for 5 iterations.
• Tests maybe flaky. Run it another time if it fails.
• Use gdb: add --gdb --no-interactive to the command, and it will automatically run the program in gdb, and print the backtrace if it crashes. This is useful for debugging.