RFR: 8351594: JFR: Rate-limited sampling of Java events

[Markus Grönlund]

On Fri, 30 May 2025 22:30:25 GMT, Erik Gahlin <egahlin at openjdk.org> wrote:

> Could I have review of an enhancement that adds rate-limited sampling to Java event, including five events in the JDK (SocketRead, SocketWrite, FileRead, FileWrite, and JavaExceptionThrow).
> 
> Testing: test/jdk/jdk/jfr
> 
> Thanks
> Erik

src/jdk.jfr/share/classes/jdk/jfr/internal/settings/Throttler.java line 142:

> 140:     private long deriveSamplingInterval(double sampleSize, ThrottlerWindow expired) {
> 141:         double populationSize = projectPopulationSize(expired);
> 142:         if (adjustBoundary(populationSize) <= adjustBoundary(sampleSize)) {

Do you need all these adjustBoundary() calls? It only checks if a double value is 0 or 1. Population and sample sizes will be much larger.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25559#discussion_r2119471003