On Sun, 1 Jun 2025 07:26:19 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 two > additional commits since the last revision: > > - Refactoring > - Remove convoluted native trace logic src/hotspot/share/jfr/periodic/sampling/jfrThreadSampling.cpp line 362: > 360: drain_enqueued_requests(now, tl, jt, current); > 361: #ifdef LINUX > 362: if (tl->has_cpu_time_jfr_requests()) { You are having all threads traverse over this lock, even though the cpu time sampler is disabled by default. Can it be improved? src/hotspot/share/jfr/support/jfrThreadLocal.cpp line 604: > 602: > 603: bool JfrThreadLocal::has_cpu_time_jfr_requests() { > 604: return Atomic::load(&_has_cpu_time_jfr_requests); Atomic::load_acquire() src/hotspot/share/jfr/support/jfrThreadLocal.cpp line 620: > 618: > 619: bool JfrThreadLocal::wants_async_processing_of_cpu_time_jfr_requests() { > 620: return Atomic::load(&_do_async_processing_of_cpu_time_jfr_requests); Atomic::load_acquire() ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/25302#discussion_r2119242319 PR Review Comment: https://git.openjdk.org/jdk/pull/25302#discussion_r2119243305 PR Review Comment: https://git.openjdk.org/jdk/pull/25302#discussion_r2119243393
