On Thu, 30 Apr 2026 02:38:13 GMT, Serguei Spitsyn <[email protected]> wrote:
>> This change fixes a long standing performance issue related to the debugger >> single stepping that is using JVMTI `FramePop` events as a part of step over >> handling. The performance issue is that the target thread continues its >> execution in very slow `interp-only` mode in a context of frame marked for >> `FramePop` notification with the JVMTI `NotifyFramePop`. It includes other >> method calls recursively upon a return from the frame. >> >> This fix is to avoid enforcing the `interp-only` execution mode for threads >> when `FramePop` events are enabled with the JVMTI >> `SetEventNotificationMode()`. Instead, the target frame has been deoptimized >> and kept interpreted by disabling `OSR` optimization by the function >> `InterpreterRuntime::frequency_counter_overflow_inner()`. (Big thanks to >> @fisk for this suggestion!) Additionally, some tweaks are applied in several >> places where the `java_thread->is_interp_only_mode()` is checked. >> The other details will be provided in the first PR request comment. >> >> Testing: >> - test `serviceability/jvmti/vthread/ThreadStateTest` was updated to >> provide some extra test coverage >> - submitted mach5 tiers 1-6 >> >> - [x] I confirm that I make this contribution in accordance with the >> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). > > Serguei Spitsyn has updated the pull request with a new target base due to a > merge or a rebase. The pull request now contains 28 commits: > > - Merge > - review: 1. move set_frame_pop call; 2. decrease test execution time and > its timeout > - review: (1) remove unneeded assert, (2) simplify one statement in > JvmtiEnvBase::set_frame_pop > - update copyright year > - review: (1) rename one method (2) remove unneeded changes > - review: renamed test to StepOverStressTest.java > - fix some merge error > - add com/sun/jdi performance test: SingleStepPerformanceTest.java > - add test coverage for two FramePop event requests > - fix one previous merge conlict error > - ... and 18 more: https://git.openjdk.org/jdk/compare/69455d59...0272af1b I've simplified the deopt approach which is to get rid of the pending deopts. The mach5 testing with tiers 1-6 looks good so far. So, I've pushed this update. ------------- PR Comment: https://git.openjdk.org/jdk/pull/28407#issuecomment-4356694794
