On Thu, 20 Nov 2025 02:24:52 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). This pull request has now been integrated. Changeset: 7da24777 Author: Serguei Spitsyn <[email protected]> URL: https://git.openjdk.org/jdk/commit/7da2477700a976e628d0cd18daa3e1e6d959a463 Stats: 500 lines in 28 files changed: 390 ins; 34 del; 76 mod 6960970: Debugger very slow during stepping Co-authored-by: Patricio Chilano Mateo <[email protected]> Reviewed-by: lmesnik, pchilanomate ------------- PR: https://git.openjdk.org/jdk/pull/28407
