The purpose of this change is to reduce the size of JFR recordings when the OldObjectSample event is enabled.
## Problem
JFR recordings size blows up when the `OldObjectSample` is enabled. The memory allocation events are known to be very high traffic and will cause a lot of data, just the sheer number of events produced, and if stacktraces are added to this, the associated metadata can be huge as well. Sampled object are stored in a priority queue and their associated stack traces stored in `JFRStackTraceRepository`. When sample candidates are removed from the priority queue, their stacktraces remain in the repository, which will be later written at chunk rotation even if the sample has been removed.
## Implementation
This PR adds a `JFRStackTraceRepository` dedicated to store stack traces for the `OldObjectSample` event. At chunk rotation, every sample stack trace is looked up in this repository and is serialized. Other stack traces are simply removed.
## Benchmarks
On an AWS c5.metal instance (96 cores, 192 Gib), running SPECjvm2008 with default profile.jfc configuration with OldObjectSample event enabled gives
- a recording size 2.78Mb with the PR fix
- a recording size 20.73Mb with the PR fix
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Commit messages:
- Add ObjectSamplerStackTraceRepository
- Add objecetSampleCheckpoint.cpp StackTraceChunkWriter
- Instanciate leak profiler StackTraceRepository
- Add leak profiler StackTraceRepository
- Un-statify jfrStackTraceRepository
Changes:
https://git.openjdk.java.net/jdk/pull/2644/files Webrev:
https://webrevs.openjdk.java.net/?repo=jdk&pr=2644&range=00 Issue:
https://bugs.openjdk.java.net/browse/JDK-8258414 Stats: 189 lines in 16 files changed: 163 ins; 1 del; 25 mod
Patch:
https://git.openjdk.java.net/jdk/pull/2644.diff Fetch: git fetch
https://git.openjdk.java.net/jdk pull/2644/head:pull/2644
PR:
https://git.openjdk.java.net/jdk/pull/2644
Locked
