Don't preload jmethodIDs when cstack=vm with hotspot JVM by zhengyu123 · Pull Request #549 · DataDog/java-profiler

zhengyu123 · 2026-05-27T20:10:57Z

What does this PR do?:
Reduce memory overhead by storing raw Method pointers instead of pre-allocating jmethodIDs for classes loaded by system class loaders (bootstrap, platform and application)

This feature only applies to hotspot JVM when cstack=vm

Motivation:
Pre-allocating jmethodIDs can consume significant amount of native memory, e.g. 9G in some extreme cases.
By introducing optional lazy jmethodID resolution for system classes, HotSpot JVM profiling avoids loading jmethodIDs for every method, but only the methods on stacks, a significant optimization for native memory usage.

Additional Notes:
This feature is optional and is off by default. To enable the feature, set force_jmethodID=false

How to test the change?:
Running renaissance akka benchmark with NMT, exams jmethodID sites:

Mainline (without this PR)

[0x0000726344c5f43d] InstanceKlass::get_jmethod_id(methodHandle const&)+0x8d
[0x000072634500e78a] Method::jmethod_id()+0x6a
[0x0000726344e78f63] JvmtiEnv::GetClassMethods(oopDesc*, int*, _jmethodID***)+0x2b3
[0x0000726344e2eb86] jvmti_GetClassMethods+0x206
                             (malloc=430672 type=Class #3156) (at peak)

[0x000072634500d4d1] Method::ensure_jmethod_ids(ClassLoaderData*, int)+0xd1
[0x0000726344e78f57] JvmtiEnv::GetClassMethods(oopDesc*, int*, _jmethodID***)+0x2a7
[0x0000726344e2eb86] jvmti_GetClassMethods+0x206
[0x0000726344145374] _jvmtiEnv::GetClassMethods(_jclass*, int*, _jmethodID***)+0x34
                             (malloc=392776 type=Internal #2397) (at peak)

[0x000072634500d48d] Method::ensure_jmethod_ids(ClassLoaderData*, int)+0x8d
[0x0000726344e78f57] JvmtiEnv::GetClassMethods(oopDesc*, int*, _jmethodID***)+0x2a7
[0x0000726344e2eb86] jvmti_GetClassMethods+0x206
[0x0000726344145374] _jvmtiEnv::GetClassMethods(_jclass*, int*, _jmethodID***)+0x34
                             (malloc=57528 type=Class #2397) (at peak)

With force_jmethodID=false

[0x0000762891b93651] Method::ensure_jmethod_ids(ClassLoaderData*, int)+0x251
[0x00007628919fef57] JvmtiEnv::GetClassMethods(oopDesc*, int*, _jmethodID***)+0x2a7
[0x00007628919b4b86] jvmti_GetClassMethods+0x206
[0x0000762890ce9594] _jvmtiEnv::GetClassMethods(_jclass*, int*, _jmethodID***)+0x34
                             (malloc=3920 type=Class #98) (at peak)

[0x0000762891b93850] Method::make_jmethod_id(ClassLoaderData*, Method*)+0x90
[0x00007628917e548d] InstanceKlass::get_jmethod_id(methodHandle const&)+0xdd
[0x0000762891b9478a] Method::jmethod_id()+0x6a
[0x00007628918a0186] get_method_id(JNIEnv_*, _jclass*, char const*, char const*, bool, JavaThread*) [clone .constprop.0]+0x186
                             (malloc=1536 type=Class #64) (at peak)

[0x00007628917e543d] InstanceKlass::get_jmethod_id(methodHandle const&)+0x8d
[0x0000762891b9478a] Method::jmethod_id()+0x6a
[0x00007628919fef63] JvmtiEnv::GetClassMethods(oopDesc*, int*, _jmethodID***)+0x2b3
[0x00007628919b4b86] jvmti_GetClassMethods+0x206
                             (malloc=252656 type=Class #1792) (at peak)

For Datadog employees:

If this PR touches code that signs or publishes builds or packages, or handles
credentials of any kind, I've requested a review from @DataDog/security-design-and-guidance.
This PR doesn't touch any of that.
JIRA: PROF-13548

Unsure? Have a question? Request a review!

datadog-official · 2026-05-27T20:15:04Z

✨ Fix all issues with BitsAI

⚠️ Warnings

🚦 21 Pipeline jobs failed

CI Run | test-matrix / test-linux-musl-aarch64 (11-librca, debug)

CI Run | test-matrix / test-linux-musl-aarch64 (17-librca, debug)

CI Run | test-matrix / test-linux-musl-aarch64 (21-librca, debug)

View all 21 failed jobs.

Useful? React with 👍 / 👎

_{This comment will be updated automatically if new data arrives.

🔗 Commit SHA: ce46bdf | Docs | Datadog PR Page | Give us feedback!}

dd-octo-sts · 2026-05-27T20:32:32Z

CI Test Results

Run: #28111186664 | Commit: 3ce2d59 | Duration: 14m 2s (longest job)

❌ 5 of 32 test jobs failed

Status Overview

JDK	glibc-aarch64/debug	glibc-amd64/debug	musl-aarch64/debug	musl-amd64/debug
8	-	✅	-	-
8-ibm	-	✅	-	-
8-j9	✅	✅	-	-
8-librca	-	-	❌	✅
8-orcl	-	✅	-	-
11	-	✅	-	-
11-j9	✅	✅	-	-
11-librca	-	-	❌	✅
17	✅	✅	-	-
17-graal	✅	✅	-	-
17-j9	✅	✅	-	-
17-librca	-	-	❌	✅
21	✅	✅	-	-
21-graal	✅	✅	-	-
21-librca	-	-	❌	✅
25	✅	✅	-	-
25-graal	✅	✅	-	-
25-librca	-	-	❌	✅

Legend: ✅ passed | ❌ failed | ⚪ skipped | 🚫 cancelled

Failed Tests

musl-aarch64/debug / 8-librca

Job: View logs

No detailed failure information available. Check the job logs.

musl-aarch64/debug / 25-librca

Job: View logs

No detailed failure information available. Check the job logs.

musl-aarch64/debug / 17-librca

Job: View logs

No detailed failure information available. Check the job logs.

musl-aarch64/debug / 11-librca

Job: View logs

No detailed failure information available. Check the job logs.

musl-aarch64/debug / 21-librca

Job: View logs

No detailed failure information available. Check the job logs.

Summary: Total: 32 | Passed: 27 | Failed: 5

Updated: 2026-06-24 16:06:30 UTC

dd-octo-sts · 2026-05-31T19:09:17Z

Scan-Build Report

User:	runner@runnervm3jyl0
Working Directory:	/home/runner/work/java-profiler/java-profiler/ddprof-lib/src/test/make
Command Line:	make -j4 all
Clang Version:	Ubuntu clang version 18.1.3 (1ubuntu1)
Date:	Tue Jun 2 20:41:00 2026

Bug Summary

Logic error
Bug Type	Quantity	Display?
All Bugs	1
Result of operation is garbage or undefined	1

Reports

Bug Group	Bug Type ▾	File	Function/Method	Line	Path Length
Logic error	Result of operation is garbage or undefined	hotspotSupport.cpp	loadMethodIDsImpl	1309	2

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 13349c38df

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: b95c88c66f

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: df5e992559

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: b41f1b337c

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

This reverts commit b41f1b3.

rkennke

Some things you said you fixed are still not fixed, and I also found a new thing.

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 370e84d0f8

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 0154c29ef8

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 5dc6ca7689

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 9310d2ccbd

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 3d6b19fa97

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: a5f1f70551

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 4da9b18b47

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 52f6f0e785

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

dd-octo-sts · 2026-06-23T21:36:55Z

Reliability & Chaos Results

❌ 1 failure(s) detected Pipeline: https://gitlab.ddbuild.io/DataDog/java-profiler/-/pipelines/120816936

❌ chaos: profiler tcmalloc amd64 21 0 3 temXchaos

Chaos harness crashed (RC=124)
siginfo: si_signo: 11 (SIGSEGV), si_code: 2 (SEGV_ACCERR), si_addr: 0x0000753510090e20
# C  [libjavaProfiler-dd-tmp10927298120611365694.so+0x56390]  LinuxThreadList::next()+0x0

Co-authored-by: Roman Kennke <roman.kennke@datadoghq.com>

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 88be3befe7

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

… hs_jmethod_id

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: ce46bdfdc2

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

zhengyu123 added 2 commits May 27, 2026 18:20

Don't preload jmethodIDs when cstack=vm with hotspot JVM

5f5fa35

v1

4e3bf98

zhengyu123 added 2 commits May 28, 2026 13:29

v2

957d27c

v3

14728a7

zhengyu123 added 11 commits June 1, 2026 12:49

Clean up

64e183b

Fix

c782c3c

Add application/platform class loader support

c462d85

Fix

7710c6f

Fix

6c6f1a7

Harden symbolAt()

07c3a4c

Merge branch 'main' into hs_jmethod_id

4827c68

force_jmethodID argument

3dda4e3

Consolidate JVM initialization

a826e7e

Cleanup: fixed typo and etc.

9d1818a

Remove dead code

13349c3

zhengyu123 marked this pull request as ready for review June 2, 2026 15:26

zhengyu123 requested a review from a team as a code owner June 2, 2026 15:26

chatgpt-codex-connector Bot reviewed Jun 2, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/hotspot/hotspotSupport.cpp

Comment thread ddprof-lib/src/main/cpp/hotspot/hotspotSupport.cpp Outdated

zhengyu123 marked this pull request as draft June 2, 2026 15:45

zhengyu123 added 2 commits June 2, 2026 16:24

Fix

06b1a92

Fix

b95c88c

zhengyu123 changed the title ~~WIP: Don't preload jmethodIDs when cstack=vm~~ Don't preload jmethodIDs when cstack=vm with hotspot JVM Jun 2, 2026

zhengyu123 marked this pull request as ready for review June 2, 2026 17:13

chatgpt-codex-connector Bot reviewed Jun 2, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/hotspot/hotspotSupport.cpp

Comment thread ddprof-lib/src/main/cpp/hotspot/hotspotSupport.cpp

Fix

df5e992

chatgpt-codex-connector Bot reviewed Jun 2, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/hotspot/hotspotSupport.cpp Outdated

zhengyu123 requested a review from jbachorik June 2, 2026 20:03

Cleanup

2bf4732

rkennke requested changes Jun 17, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/hotspot/hotspotSupport.cpp Outdated

Comment thread ddprof-lib/src/main/cpp/hotspot/hotspotSupport.cpp

Comment thread ddprof-lib/src/main/cpp/jvmSupport.inline.h Outdated

Fix

b41f1b3

chatgpt-codex-connector Bot reviewed Jun 17, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/thread.cpp Outdated

zhengyu123 added 2 commits June 17, 2026 13:37

Revert "Fix"

b524b81

This reverts commit b41f1b3.

Fix

370e84d

rkennke requested changes Jun 17, 2026

View reviewed changes

chatgpt-codex-connector Bot reviewed Jun 17, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/arguments.h Outdated

Review comments

0154c29

chatgpt-codex-connector Bot reviewed Jun 17, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/jvmSupport.inline.h Outdated

Cleanup

5dc6ca7

chatgpt-codex-connector Bot reviewed Jun 22, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/hotspot/hotspotSupport.cpp Outdated

Fix

9310d2c

chatgpt-codex-connector Bot reviewed Jun 22, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/hotspot/hotspotSupport.h Outdated

Comment thread ddprof-lib/src/main/cpp/hotspot/vmStructs.inline.h

rkennke reviewed Jun 23, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/hotspot/hotspotSupport.h Outdated

Comment thread ddprof-lib/src/main/cpp/hotspot/vmStructs.inline.h

Review comments

3d6b19f

chatgpt-codex-connector Bot reviewed Jun 23, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/frame.h Outdated

Comment thread ddprof-test/src/test/java/com/datadoghq/profiler/cpu/ClinitResolutionTest.java Outdated

Merge

a5f1f70

chatgpt-codex-connector Bot reviewed Jun 23, 2026

View reviewed changes

Comment thread ddprof-test/src/test/java/com/datadoghq/profiler/cpu/ClinitResolutionTest.java

Review

4da9b18

chatgpt-codex-connector Bot reviewed Jun 23, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/hotspot/hotspotSupport.h

Fix initExecution order

52f6f0e

chatgpt-codex-connector Bot reviewed Jun 23, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/hotspot/hotspotSupport.cpp

rkennke reviewed Jun 24, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/hotspot/hotspotSupport.cpp

Update ddprof-lib/src/main/cpp/hotspot/hotspotSupport.cpp

88be3be

Co-authored-by: Roman Kennke <roman.kennke@datadoghq.com>

chatgpt-codex-connector Bot reviewed Jun 24, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/frame.h Outdated

zhengyu123 added 2 commits June 24, 2026 15:48

Fix and comments

936d0fa

Merge branch 'hs_jmethod_id' of github.com:DataDog/java-profiler into…

ce46bdf

… hs_jmethod_id

chatgpt-codex-connector Bot reviewed Jun 24, 2026

View reviewed changes

Comment thread ddprof-lib/src/main/cpp/hotspot/hotspotSupport.cpp

Uh oh!

Conversation

zhengyu123 commented May 27, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

datadog-official Bot commented May 27, 2026 • edited by datadog-datadog-prod-us1-2 Bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

⚠️ Warnings

Uh oh!

dd-octo-sts Bot commented May 27, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

CI Test Results

Status Overview

Failed Tests

Uh oh!

dd-octo-sts Bot commented May 31, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Scan-Build Report

Bug Summary

Reports

Uh oh!

chatgpt-codex-connector Bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

Uh oh!

Uh oh!

chatgpt-codex-connector Bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

Uh oh!

Uh oh!

chatgpt-codex-connector Bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

chatgpt-codex-connector Bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

Uh oh!

rkennke left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

chatgpt-codex-connector Bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

Uh oh!

chatgpt-codex-connector Bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

Uh oh!

chatgpt-codex-connector Bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

Uh oh!

chatgpt-codex-connector Bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

chatgpt-codex-connector Bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

zhengyu123 commented May 27, 2026 •

edited

Loading

datadog-official Bot commented May 27, 2026 •

edited by datadog-datadog-prod-us1-2 Bot

Loading

dd-octo-sts Bot commented May 27, 2026 •

edited

Loading

dd-octo-sts Bot commented May 31, 2026 •

edited

Loading

dd-octo-sts Bot commented Jun 23, 2026 •

edited

Loading