On Tue, 2 Aug 2022 15:38:05 GMT, David Schlosnagle <d...@openjdk.org> wrote:
>> I would like to contribute an optimized version of >> `StackTraceElement#toString()` that uses a single StringBuilder throughout >> creation to avoid intermediate `String` allocations. >> `StackTraceElement#toString()` is used in a number of JDK code paths >> including `Throwable#printStackTrace()`, as well as many JDK consumers may >> transform `StackTraceElement` `toString()` in logging frameworks capturing >> throwables and exceptions, and diagnostics performing dumps. >> >> Given this usage and some observed JFR profiles from production services, >> I'd like to reduce the intermediate allocations to reduce CPU pressure in >> these circumstances. I have added a couple benchmarks for a sample >> `Throwable#printStackTrace()` converted to String via `StringWriter` and >> individual `StackTraceElement` `toString`. The former shows ~15% >> improvement, while the latter shows ~40% improvement. >> >> Before >> >> Benchmark Mode Cnt Score Error >> Units >> StackTraceElementBench.printStackTrace avgt 15 167147.066 ± 4260.521 >> ns/op >> StackTraceElementBench.toString avgt 15 132.781 ± 2.095 >> ns/op >> >> >> After >> >> Benchmark Mode Cnt Score Error >> Units >> StackTraceElementBench.printStackTrace avgt 15 142909.133 ± 2290.720 >> ns/op >> StackTraceElementBench.toString avgt 15 78.939 ± 0.469 >> ns/op > > David Schlosnagle has updated the pull request incrementally with two > additional commits since the last revision: > > - Mark StackTraceElement SerialTest for bug 8291641 > - Revert "Mark StackTraceElement SerialTest for bug 8291641" > > This reverts commit e7b04faafb026e61829c81c75121e2d3be6644d9. LGTM ------------- Marked as reviewed by rriggs (Reviewer). PR: https://git.openjdk.org/jdk/pull/9665
