On Tue, 19 Aug 2025 08:42:15 GMT, Jonas Norlinder <d...@openjdk.org> wrote:
>> Hi all, >> >> This PR refactors the newly added GC CPU time code from >> [JDK-8359110](https://bugs.openjdk.org/browse/JDK-8359110). >> >> As a stepping-stone to enable consolidation of CPU time tracking in e.g. >> hsperf counters and GCTraceCPUTime and to have a unified interface for >> tracking CPU time of various components in Hotspot this code can be >> refactored. This PR introduces a new interface to retrieve CPU time for >> various Hotspot components and it currently supports: >> >> CPUTimeUsage::GC::total() // the sum of gc_threads(), vm_thread(), >> stringdedup() >> >> CPUTimeUsage::GC::gc_threads() >> CPUTimeUsage::GC::vm_thread() >> CPUTimeUsage::GC::stringdedup() >> >> CPUTimeUsage::Runtime::vm_thread() >> >> >> I moved `CPUTimeUsage` to `src/hotspot/share/services` since it seemed >> fitting as it housed similar performance tracking code like >> `RuntimeService`, as this is no longer a class that is only specific to GC. >> >> I also made a minor improvement in the CPU time logging during exit. Since >> `CPUTimeUsage` supports more components than just GC I changed the logging >> flag to from `gc,cpu` to `cpu` and created a detailed table: >> >> >> [71.425s][info][cpu ] === CPU time Statistics >> ============================================================= >> [71.425s][info][cpu ] >> CPUs >> [71.425s][info][cpu ] >> s % utilized >> [71.425s][info][cpu ] Process >> [71.425s][info][cpu ] Total >> 1616.3627 100.00 22.6 >> [71.425s][info][cpu ] VM Thread >> 5.2992 0.33 0.1 >> [71.425s][info][cpu ] Garbage Collection >> 83.7322 5.18 1.2 >> [71.425s][info][cpu ] GC Threads >> 82.7671 5.12 1.2 >> [71.425s][info][cpu ] VM Thread >> 0.9651 0.06 0.0 >> [71.425s][info][cpu ] >> ===================================================================================== >> >> >> Additionally, if CPU time retrieval fails it should not be the caller's >> responsibility to log warnings as this would bloat the code unnecessarily. >> I've noticed that `os` does log a warning for some methods if they fail so I >> continued on this path. > > Jonas Norlinder has updated the pull request incrementally with one > additional commit since the last revision: > > Remove unused I'll leave it to the GC folk to approve, but the shared code changes look good to me. Thanks src/hotspot/share/services/cpuTimeUsage.cpp line 2: > 1: /* > 2: * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved. When refactoring code into a new file, the first copyright year for the new file should be the earliest copyright year of the substantial code/content in that file—not the year the new file is created. ------------- PR Review: https://git.openjdk.org/jdk/pull/26621#pullrequestreview-3134573286 PR Review Comment: https://git.openjdk.org/jdk/pull/26621#discussion_r2286823424
