On Wed, 8 Apr 2026 05:04:03 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 incrementally with one > additional commit since the last revision: > > review: (1) remove unneeded assert, (2) simplify one statement in > JvmtiEnvBase::set_frame_pop Changes requested by lmesnik (Reviewer). src/hotspot/share/prims/jvmtiEnvBase.cpp line 1366: > 1364: return JVMTI_ERROR_DUPLICATE; > 1365: } > 1366: ets->set_frame_pop(frame_number); Shouldn't be moved into line 1375 to don't set_frame_pop() if JVMTI_ERROR_OPAQUE_FRAME is returned? ------------- PR Review: https://git.openjdk.org/jdk/pull/28407#pullrequestreview-4173234159 PR Review Comment: https://git.openjdk.org/jdk/pull/28407#discussion_r3140144530
