September 2023 - hotspot-jfr-dev

RFR: 8307057 JFR: Enable -XX:+DebugNonSafepoints when JFR starts
by Erik Gahlin 16 Sep '23

16 Sep '23

Could I have review of a change that enables DebugNonSafepoints when JFR starts. Testing: tier1, tier2, tier3, tier4 Thanks Erik ------------- Commit messages: - Initial Changes: https://git.openjdk.org/jdk/pull/14147/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14147&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8307057 Stats: 9 lines in 2 files changed: 9 ins; 0 del; 0 mod Patch: https://git.openjdk.org/jdk/pull/14147.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/14147/head:pull/14147 PR: https://git.openjdk.org/jdk/pull/14147

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RFR: 8315373: Change VirtualThread to unmount after freezing, re-mount before thawing
by Alan Bateman 10 Sep '23

10 Sep '23

In the virtual thread implementation, thread identity switches to the carrier before freezing and switches back to the virtual thread after thawing. This was a forced move due to issues getting JVMTI to work with virtual threads. JVMTI can now hide events during transitions so we can invert the sequence back to mounting before running the continuation, unmounting after freezing, and re-mounting after thawing. This sequence is important for future changes that will initiate the freezing from the VM. The change requires an update to the JFR thread sampler to skip sampling when it samples during a transition. Testing: tier1-5 ------------- Commit messages: - Initial commit Changes: https://git.openjdk.org/jdk/pull/15492/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15492&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8315373 Stats: 45 lines in 2 files changed: 10 ins; 16 del; 19 mod Patch: https://git.openjdk.org/jdk/pull/15492.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/15492/head:pull/15492 PR: https://git.openjdk.org/jdk/pull/15492

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Integrated: 8315930: Revert "8315220: Event NativeLibraryLoad breaks invariant by taking a stacktrace when thread is in state _thread_in_native"
by Markus Grönlund 08 Sep '23

08 Sep '23

On Fri, 8 Sep 2023 11:42:05 GMT, Markus Grönlund <mgronlun(a)openjdk.org> wrote: > Greetings, > > [JDK-8315220](https://bugs.openjdk.org/browse/JDK-8315220) hit an issue, [JDK-8315892](https://bugs.openjdk.org/browse/JDK-8315892), so we need to backout [JDK-8315220](https://bugs.openjdk.org/browse/JDK-8315220) > > This change set is the git revert. > > Testing: jdk_jfr > > Thanks > Markus This pull request has now been integrated. Changeset: b3dfc399 Author: Markus Grönlund <mgronlun(a)openjdk.org> URL: https://git.openjdk.org/jdk/commit/b3dfc399dae714958f22624daf76831c6ec2dfe0 Stats: 395 lines in 10 files changed: 114 ins; 243 del; 38 mod 8315930: Revert "8315220: Event NativeLibraryLoad breaks invariant by taking a stacktrace when thread is in state _thread_in_native" Reviewed-by: egahlin ------------- PR: https://git.openjdk.org/jdk/pull/15635

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Re: RFR: 8315930: Revert "8315220: Event NativeLibraryLoad breaks invariant by taking a stacktrace when thread is in state _thread_in_native"
by Erik Gahlin 08 Sep '23

08 Sep '23

On Fri, 8 Sep 2023 11:42:05 GMT, Markus Grönlund <mgronlun(a)openjdk.org> wrote: > Greetings, > > [JDK-8315220](https://bugs.openjdk.org/browse/JDK-8315220) hit an issue, [JDK-8315892](https://bugs.openjdk.org/browse/JDK-8315892), so we need to backout [JDK-8315220](https://bugs.openjdk.org/browse/JDK-8315220) > > This change set is the git revert. > > Testing: jdk_jfr > > Thanks > Markus Marked as reviewed by egahlin (Reviewer). ------------- PR Review: https://git.openjdk.org/jdk/pull/15635#pullrequestreview-1617364734

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Integrated: 8315220: Event NativeLibraryLoad breaks invariant by taking a stacktrace when thread is in state _thread_in_native
by Markus Grönlund 07 Sep '23

07 Sep '23

On Fri, 1 Sep 2023 12:03:39 GMT, Markus Grönlund <mgronlun(a)openjdk.org> wrote: > Greetings, > > This change set fixes the issue of taking a JFR stack trace in the wrong thread state for the NativeLibraryLoad and NativeLibraryUnload events. > > A follow-up change set, [JDK-8315364](https://bugs.openjdk.org/browse/JDK-8315364) will add assertions to the JFR stack trace code to help find similar issues earlier. > > There are a few additional improvements: > > The event declaration in metadata.xml now includes the generating thread since a stack trace without the generating thread is subpar. > > In os_linux.cpp, the NativeLibraryLoad event was located after the call to dlopen(), which means that the event, declared durational, fails to capture the duration of the call. > > Finally, the test is extended to validate the captured stack trace. > > Testing: jdk_jfr, stress testing > > Thanks > Markus This pull request has now been integrated. Changeset: 1cae0f53 Author: Markus Grönlund <mgronlun(a)openjdk.org> URL: https://git.openjdk.org/jdk/commit/1cae0f53a9d37fbae9471bd942f7157429a85cd1 Stats: 395 lines in 10 files changed: 243 ins; 114 del; 38 mod 8315220: Event NativeLibraryLoad breaks invariant by taking a stacktrace when thread is in state _thread_in_native Reviewed-by: mbaesken, egahlin ------------- PR: https://git.openjdk.org/jdk/pull/15535

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Re: RFR: 8315220: Event NativeLibraryLoad breaks invariant by taking a stacktrace when thread is in state _thread_in_native [v2]
by Markus Grönlund 07 Sep '23

07 Sep '23

> Greetings, > > This change set fixes the issue of taking a JFR stack trace in the wrong thread state for the NativeLibraryLoad and NativeLibraryUnload events. > > A follow-up change set, [JDK-8315364](https://bugs.openjdk.org/browse/JDK-8315364) will add assertions to the JFR stack trace code to help find similar issues earlier. > > There are a few additional improvements: > > The event declaration in metadata.xml now includes the generating thread since a stack trace without the generating thread is subpar. > > In os_linux.cpp, the NativeLibraryLoad event was located after the call to dlopen(), which means that the event, declared durational, fails to capture the duration of the call. > > Finally, the test is extended to validate the captured stack trace. > > Testing: jdk_jfr, stress testing > > Thanks > Markus Markus Grönlund has updated the pull request incrementally with one additional commit since the last revision: renaming and commentary ------------- Changes: - all: https://git.openjdk.org/jdk/pull/15535/files - new: https://git.openjdk.org/jdk/pull/15535/files/aa4bc48a..b0094b7f Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=15535&range=01 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15535&range=00-01 Stats: 32 lines in 2 files changed: 11 ins; 0 del; 21 mod Patch: https://git.openjdk.org/jdk/pull/15535.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/15535/head:pull/15535 PR: https://git.openjdk.org/jdk/pull/15535

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Re: RFR: 8315220: Event NativeLibraryLoad breaks invariant by taking a stacktrace when thread is in state _thread_in_native
by Matthias Baesken 07 Sep '23

07 Sep '23

On Fri, 1 Sep 2023 12:03:39 GMT, Markus Grönlund <mgronlun(a)openjdk.org> wrote: > Greetings, > > This change set fixes the issue of taking a JFR stack trace in the wrong thread state for the NativeLibraryLoad and NativeLibraryUnload events. > > A follow-up change set, [JDK-8315364](https://bugs.openjdk.org/browse/JDK-8315364) will add assertions to the JFR stack trace code to help find similar issues earlier. > > There are a few additional improvements: > > The event declaration in metadata.xml now includes the generating thread since a stack trace without the generating thread is subpar. > > In os_linux.cpp, the NativeLibraryLoad event was located after the call to dlopen(), which means that the event, declared durational, fails to capture the duration of the call. > > Finally, the test is extended to validate the captured stack trace. > > Testing: jdk_jfr, stress testing > > Thanks > Markus LGTM (we tested it also for some days in our internal infrastructure) ------------- Marked as reviewed by mbaesken (Reviewer). PR Review: https://git.openjdk.org/jdk/pull/15535#pullrequestreview-1615524142

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