Add force jmethodID experimental feature support by zhengyu123 · Pull Request #11549 · DataDog/dd-trace-java

zhengyu123 · 2026-06-03T13:32:46Z

What Does This Do

This PR adds an experimental flag profiling.experimental.ddprof.jmethodid_optim.enabled to enable ddprof feature that aims to reduce pre-loading jmethodIDs for system classes.

The flag is off (false) by default to preserve current behavior.

Motivation

Preloading all jmethodIDs is proved to be a memory footprint issue. In an extreme case, it consumed 9GB native memory.

ddprof is experimenting a way to lessen dependency on jmethod IDs: none lambda and hidden classes that are loaded by system class loaders (bootstrap, platform and application class loaders), never unloaded. Instead of storing jmethod IDs for the methods of the classes, ddprof stores raw method pointers and resolves at dumping time. Therefore, ddprof does not preload jmethod IDs of none-lambda/hidden classes from those class loaders.

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Jira ticket: [PROJ-IDENT]

…dd-trace-java into zgu/experimental_reduce_jmethod

datadog-prod-us1-3 · 2026-06-03T13:32:53Z

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 56.92% (-0.01%)

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🔗 Commit SHA: b61ddef | Docs | Datadog PR Page | Give us feedback!}

dd-octo-sts · 2026-06-03T13:36:58Z

🟢 Java Benchmark SLOs — All performance SLOs passed

Suite	Status
Startup	🟢 pass

SLO thresholds are defined here based on automatically generated metrics. A warning is raised when results are within 5% of the threshold.

PR vs. master results

Scenario	Candidate	master	Δ (95% CI of mean)
startup:insecure-bank:iast:Agent	13.98 s	13.92 s	[-0.3%; +1.2%] (no difference)
startup:insecure-bank:tracing:Agent	12.90 s	12.97 s	[-1.2%; +0.1%] (no difference)
startup:petclinic:appsec:Agent	16.80 s	16.76 s	[-0.8%; +1.2%] (no difference)
startup:petclinic:iast:Agent	16.89 s	16.94 s	[-1.2%; +0.6%] (no difference)
startup:petclinic:profiling:Agent	16.52 s	16.85 s	[-3.2%; -0.8%] (maybe better)
startup:petclinic:sca:Agent	16.98 s	16.79 s	[+0.1%; +2.1%] (maybe worse)
startup:petclinic:tracing:Agent	16.13 s	15.58 s	[-0.9%; +7.9%] (no difference)

Commit: b61ddef2 · CI Pipeline · Benchmarking Platform UI

Load and DaCapo benchmarks can be triggered manually in the GitLab pipeline. Results will appear in the Benchmarking Platform UI after completion.

…figurations.json

Copilot

Pull request overview

Adds an experimental profiling configuration flag to control ddprof’s “force jmethodID preloading” behavior, aiming to reduce native memory usage by allowing jmethodID preloading to be disabled for eligible classes while preserving current behavior by default.

Changes:

Added a new profiling config key + default for profiling.experimental.ddprof.force_jmethodID.
Wired the flag into ddprof start command generation (emit fjmethodid=false when disabled).
Exposed the flag in supported-config metadata and in the profiler flare configuration output.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
metadata/supported-configurations.json	Registers the new env var metadata entry for the experimental ddprof flag.
dd-trace-api/src/main/java/datadog/trace/api/config/ProfilingConfig.java	Introduces the public config constant and default value for the new flag.
dd-java-agent/agent-profiling/profiling-ddprof/src/main/java/com/datadog/profiling/ddprof/DatadogProfilerConfig.java	Adds a helper accessor to read the boolean config from `ConfigProvider`.
dd-java-agent/agent-profiling/profiling-ddprof/src/main/java/com/datadog/profiling/ddprof/DatadogProfiler.java	Appends the ddprof command option when the flag is set to disable forcing jmethodID preloading.
dd-java-agent/agent-profiling/profiling-controller/src/main/java/com/datadog/profiling/controller/ProfilerFlareReporter.java	Includes the new flag in flare-reported profiler configuration output.

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…dd-trace-java into zgu/experimental_reduce_jmethod

Copilot

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Co-authored-by: Copilot Autofix powered by AI <[email protected]>

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jbachorik

Looking good. Thanks!

dd-octo-sts · 2026-07-07T17:25:40Z

/merge

gh-worker-devflow-routing-ef8351 · 2026-07-07T17:25:44Z

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2026-07-07 17:25:43 UTC ℹ️ Start processing command /merge

2026-07-07 17:25:48 UTC ℹ️ MergeQueue: pull request added to the queue

The expected merge time in master is approximately 1h (p90).

2026-07-07 18:24:33 UTC ℹ️ MergeQueue: This merge request was merged

Added force jmethodID experimental feature support Fix Merge branch 'zgu/experimental_reduce_jmethod' of github.com:DataDog/dd-trace-java into zgu/experimental_reduce_jmethod Add DD_PROFILING_EXPERIMENTAL_DDPROF_FORCE_JMETHODID to supported-configurations.json Fix Merge branch 'master' into zgu/experimental_reduce_jmethod Merge branch 'master' into zgu/experimental_reduce_jmethod Potential fix for pull request finding Co-authored-by: Copilot Autofix powered by AI <[email protected]> AI reviews Merge branch 'zgu/experimental_reduce_jmethod' of github.com:DataDog/dd-trace-java into zgu/experimental_reduce_jmethod Potential fix for pull request finding Co-authored-by: Copilot Autofix powered by AI <[email protected]> AI review comment Fix config-inversion-linter failure Fix checkConfigStrings Merge branch 'master' into zgu/experimental_reduce_jmethod Merge branch 'master' into zgu/experimental_reduce_jmethod Addressed review comments Create tmp file for recording Fix Replacing Path.of() due to language level Co-authored-by: jbachorik <[email protected]> Co-authored-by: devflow.devflow-routing-intake <[email protected]>

zhengyu123 added 3 commits June 3, 2026 08:54

Added force jmethodID experimental feature support

db68996

Fix

a7c9f1b

Merge branch 'zgu/experimental_reduce_jmethod' of github.com:DataDog/…

d8379fb

…dd-trace-java into zgu/experimental_reduce_jmethod

zhengyu123 added type: feature Enhancements and improvements comp: profiling Profiling labels Jun 3, 2026

zhengyu123 added 4 commits June 3, 2026 10:23

Add DD_PROFILING_EXPERIMENTAL_DDPROF_FORCE_JMETHODID to supported-con…

ce4ae9b

…figurations.json

Fix

0c12bd9

Merge branch 'master' into zgu/experimental_reduce_jmethod

bbf7ae2

Merge branch 'master' into zgu/experimental_reduce_jmethod

2f0deb9

zhengyu123 requested a review from Copilot July 6, 2026 19:41

Copilot started reviewing on behalf of zhengyu123 July 6, 2026 19:41 View session

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Comment thread dd-trace-api/src/main/java/datadog/trace/api/config/ProfilingConfig.java Outdated

Comment thread metadata/supported-configurations.json Outdated

Comment thread ...t-profiling/profiling-ddprof/src/main/java/com/datadog/profiling/ddprof/DatadogProfiler.java

zhengyu123 and others added 3 commits July 6, 2026 21:47

Potential fix for pull request finding

40a9a29

Co-authored-by: Copilot Autofix powered by AI <[email protected]>

AI reviews

792514b

Merge branch 'zgu/experimental_reduce_jmethod' of github.com:DataDog/…

6f4bb68

…dd-trace-java into zgu/experimental_reduce_jmethod

zhengyu123 requested a review from Copilot July 6, 2026 20:35

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Comment thread dd-trace-api/src/main/java/datadog/trace/api/config/ProfilingConfig.java Outdated

Comment thread ...ofiling-controller/src/main/java/com/datadog/profiling/controller/ProfilerFlareReporter.java Outdated

zhengyu123 and others added 4 commits July 6, 2026 22:39

Potential fix for pull request finding

0089bd1

Co-authored-by: Copilot Autofix powered by AI <[email protected]>

AI review comment

d201f80

Fix config-inversion-linter failure

7b919f5

Fix checkConfigStrings

94654d0

zhengyu123 marked this pull request as ready for review July 7, 2026 11:09

zhengyu123 requested review from a team as code owners July 7, 2026 11:09

zhengyu123 requested review from amarziali and removed request for a team July 7, 2026 11:09

dd-octo-sts Bot added the tag: ai generated Largely based on code generated by an AI or LLM label Jul 7, 2026

zhengyu123 requested a review from jbachorik July 7, 2026 11:10

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Comment thread ...t-profiling/profiling-ddprof/src/main/java/com/datadog/profiling/ddprof/DatadogProfiler.java

Merge branch 'master' into zgu/experimental_reduce_jmethod

58bd920

jbachorik reviewed Jul 7, 2026

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Comment thread dd-trace-api/src/main/java/datadog/trace/api/config/ProfilingConfig.java Outdated

Merge branch 'master' into zgu/experimental_reduce_jmethod

942285a

amarziali reviewed Jul 7, 2026

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Comment thread ...ofiling/profiling-ddprof/src/test/java/com/datadog/profiling/ddprof/DatadogProfilerTest.java Outdated

zhengyu123 added 3 commits July 7, 2026 09:33

Addressed review comments

d66316b

Create tmp file for recording

0bec0ad

Fix

dc47563

jbachorik approved these changes Jul 7, 2026

View reviewed changes

Replacing Path.of() due to language level

b61ddef

amarziali approved these changes Jul 7, 2026

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zhengyu123 added this pull request to the merge queue Jul 7, 2026

github-merge-queue Bot removed this pull request from the merge queue due to failed status checks Jul 7, 2026

gh-worker-dd-mergequeue-cf854d Bot merged commit f767846 into master Jul 7, 2026
785 of 787 checks passed

gh-worker-dd-mergequeue-cf854d Bot deleted the zgu/experimental_reduce_jmethod branch July 7, 2026 18:24

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What Does This Do

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