On Mon, 2 Jun 2025 13:50:49 GMT, Johannes Bechberger <jbechber...@openjdk.org> wrote:
>> This is the code for the [JEP 509: CPU Time based profiling for >> JFR](https://openjdk.org/jeps/509). >> >> Currently tested using [this test >> suite](https://github.com/parttimenerd/basic-profiler-tests). This runs >> profiles the [Renaissance](https://renaissance.dev/) benchmark with >> - ... different heap sizes >> - ... different GCs >> - ... different samplers (the standard JFR and the new CPU Time Sampler and >> both) >> - ... different JFR recording durations >> - ... different chunk-sizes > > Johannes Bechberger has updated the pull request incrementally with one > additional commit since the last revision: > > Fix bug related to async stack walking Scanned this briefly, would do another pass tomorrow. src/hotspot/share/jfr/periodic/sampling/jfrCPUTimeThreadSampler.cpp line 117: > 115: > 116: bool JfrCPUTimeTraceQueue::is_empty() const { > 117: return Atomic::load(&_head) == 0; Not entirely clear what is the memory semantics for accessing `_head`. Does it need to be acq/rel? If so, this one should be `::load_acquire`? src/hotspot/share/memory/resourceArea.hpp line 46: > 44: // A ResourceArea is an Arena that supports safe usage of ResourceMark. > 45: class ResourceArea: public Arena { > 46: All the changes in this file are unnecessary, please revert. src/jdk.jfr/share/classes/jdk/jfr/internal/JVM.java line 281: > 279: * @param autoadapt true if the rate should be adapted automatically > 280: */ > 281: public static native void setCPUThrottle(double rate, boolean > autoadapt); Suggestion: public static native void setCPUThrottle(double rate, boolean autoAdapt); test/jdk/jdk/jfr/event/profiling/TestSamplingLongPeriod.java line 42: > 40: public class TestSamplingLongPeriod { > 41: > 42: static String sampleEvent = EventNames.ExecutionSample; Does not look necessary to change? ------------- PR Review: https://git.openjdk.org/jdk/pull/25302#pullrequestreview-2888004951 PR Review Comment: https://git.openjdk.org/jdk/pull/25302#discussion_r2121900364 PR Review Comment: https://git.openjdk.org/jdk/pull/25302#discussion_r2121610476 PR Review Comment: https://git.openjdk.org/jdk/pull/25302#discussion_r2121587105 PR Review Comment: https://git.openjdk.org/jdk/pull/25302#discussion_r2121584954
