add TaskBlock events for blocking intervals by kaahos · Pull Request #570 · DataDog/java-profiler

kaahos · 2026-06-01T13:42:52Z

What does this PR do?:

Adds datadog.TaskBlock JFR events for blocking intervals such as LockSupport.park, Object.wait, monitor contention, including recording APIs used by dd-trace-java for instrumented blocking operations such as Thread.sleep.

Motivation:

This builds on paul.fournillon/wallclock-suppression (#560) by preserving visibility into blocked spans as explicit duration events.

Additional Notes:

This PR does not add the dd-trace-java instrumentation itself; Thread.sleep emission depends on that side calling the new profiler APIs. Monitor callback support is HotSpot-specific, and virtual-thread carrier attribution is avoided.

How to test the change?:

./.claude/commands/build-and-summarize :ddprof-test:testDebug -Ptests="*.wallclock.*TaskBlockTest"
./.claude/commands/build-and-summarize :ddprof-lib:gtestDebug

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: [JIRA-14354]

Unsure? Have a question? Request a review!

datadog-datadog-prod-us1-2 · 2026-06-01T13:54:49Z

Tests

✨ Fix all issues with BitsAI

⚠️ Warnings

🚦 1 Pipeline job failed

DataDog/java-profiler | reliability-chaos-amd64: [profiler, tcmalloc, 21.0.3-tem]

ℹ️ Info

🔄 Datadog auto-retried 3 jobs - 2 passed on retry

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

🔗 Commit SHA: 38362a0 | Docs | Datadog PR Page | Give us feedback!}

dd-octo-sts · 2026-06-01T13:57:37Z

CI Test Results

Run: #28882397887 | Commit: 85928e0 | Duration: 14m 50s (longest job)

✅ All 32 test jobs passed

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

Summary: Total: 32 | Passed: 32 | Failed: 0

Updated: 2026-07-07 16:52:18 UTC

kaahos · 2026-06-03T13:20:47Z

@copilot review this PR

Copilot · 2026-06-03T13:26:39Z

@copilot review this PR

Reviewed and found a flaky assertion in NativeSocketTaskBlockTest: it required zero TaskBlock events globally, which can fail when an untraced socket op emits one. Fixed in d21e493 by asserting that no TaskBlock is emitted for the traced span specifically, and re-ran :ddprof-test:testDebug -Ptests="*.wallclock.*TaskBlockTest" successfully.

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jbachorik · 2026-06-30T06:12:02Z

🗿 🤖 🔴

[Sphinx Review — INFO] ddprof-lib/src/main/cpp/vmEntry.cpp line 557

The wallPrecheck parameter of VM::initProfilerBridge is immediately silenced with (void)wallPrecheck and never used; the actual _wall_precheck flag is read from Arguments during Profiler::start(), making the parameter misleading.

Suggestion: Either remove the wallPrecheck parameter from initProfilerBridge and its callers, or add a comment explaining that it is intentionally ignored at bridge-init time.

dd-octo-sts · 2026-07-02T13:52:22Z

Benchmark Results

Pipeline: https://gitlab.ddbuild.io/DataDog/apm-reliability/benchmarking-platform/-/pipelines/122365137 Commit: b7db495593670f5e3ba4c153b225734b7124d463

⚠️ Significant outliers

🟢 future-genetic (JDK 25): runtime -7.3% (2074→1923 ms)
🔴 reactors (JDK 25): runtime +4.8% (17735→18593 ms)
⚠️ fj-kmeans (JDK 21): wallclock unwinds skipped — latest 0 → dev 1247 (new)

Runtime details (per benchmark × JDK)

Benchmark	JDK	Latest	Dev	Δ (dev vs latest)	Issues L/D
akka-uct	21	✅ 10414 ms (7 iters)	✅ 10412 ms (7 iters)	≈ -0% (±20.7%)	— / —
akka-uct	25	✅ 8774 ms (8 iters)	✅ 9037 ms (8 iters)	≈ +3% (±22.5%)	— / —
finagle-chirper	21	✅ 5988 ms (11 iters)	✅ 6043 ms (11 iters)	≈ +0.9% (±45.5%)	⚠️ W:1 / ⚠️ W:1
finagle-chirper	25	✅ 5445 ms (12 iters)	✅ 5507 ms (12 iters)	≈ +1.1% (±43.1%)	⚠️ W:1 / ⚠️ W:1
fj-kmeans	21	✅ 2817 ms (22 iters)	✅ 2808 ms (22 iters)	≈ -0.3% (±4.4%)	— / —
fj-kmeans	25	✅ 2842 ms (22 iters)	✅ 2843 ms (22 iters)	≈ +0% (±4.5%)	— / —
future-genetic	21	✅ 2023 ms (31 iters)	✅ 2052 ms (30 iters)	≈ +1.4% (±4.3%)	— / —
future-genetic	25	✅ 2074 ms (30 iters)	✅ 1923 ms (32 iters)	🟢 -7.3%	— / —
naive-bayes	21	✅ 1232 ms (46 iters)	✅ 1233 ms (46 iters)	≈ +0.1% (±57%)	— / —
naive-bayes	25	✅ 925 ms (61 iters)	💥 0 ms (0 iters)	—	— / —
reactors	21	✅ 16521 ms (5 iters)	✅ 17662 ms (5 iters)	≈ +6.9% (±13.4%)	— / —
reactors	25	✅ 17735 ms (5 iters)	✅ 18593 ms (5 iters)	🔴 +4.8%	— / —

Internal counter details (ddprof)

ddprof internal counters, latest / dev (✅ = 0, · = unavailable):

Benchmark	JDK	Dropped rec	Dropped jvmti	Dropped trace	Skipped WC	AGCT fail	Unwind fail
akka-uct	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
akka-uct	25	✅ / ✅	✅ / ✅	4 / 3	2115 / 2356	✅ / ✅	✅ / ✅
finagle-chirper	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
finagle-chirper	25	✅ / ✅	✅ / ✅	✅ / 2	8348 / 8213	✅ / ✅	✅ / ✅
fj-kmeans	21	✅ / ✅	✅ / ✅	✅ / 1	✅ / 1247	✅ / ✅	✅ / ✅
fj-kmeans	25	✅ / ✅	✅ / ✅	1 / 2	1278 / 1278	✅ / ✅	✅ / ✅
future-genetic	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
future-genetic	25	✅ / ✅	✅ / ✅	✅ / 2	2918 / 2051	✅ / ✅	✅ / ✅
naive-bayes	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
reactors	21	✅ / ✅	✅ / ✅	✅ / 2	1700 / 1851	✅ / ✅	✅ / ✅
reactors	25	✅ / ✅	✅ / ✅	✅ / 1	1817 / 1889	✅ / ✅	✅ / ✅

dd-octo-sts · 2026-07-02T16:39:03Z

Reliability & Chaos Results

❌ 1 failure(s) detected Pipeline: https://gitlab.ddbuild.io/DataDog/java-profiler/-/pipelines/123745876

❌ chaos: profiler tcmalloc amd64 21 0 3 temXchaos

Chaos harness crashed (RC=124)
siginfo: si_signo: 11 (SIGSEGV), si_code: 1 (SEGV_MAPERR), si_addr: 0x0000000000000000
# C  [libjavaProfiler-dd-tmp9981091628585413870.so+0x14600]

dd-octo-sts · 2026-07-03T08:49:09Z

Benchmark Results (commit `36f3db5`)

Pipeline: https://gitlab.ddbuild.io/DataDog/apm-reliability/benchmarking-platform/-/pipelines/122534005 Commit: 36f3db52d66680198bd5ce6ed0dcc3fc73aca40c

⚠️ Significant outliers

🔴 future-genetic (JDK 25): runtime +7.4% (1913→2054 ms)
🔴 reactors (JDK 25): runtime +7.5% (17266→18553 ms)

Runtime details (per benchmark × JDK)

Benchmark	JDK	Latest	Dev	Δ (dev vs latest)	Issues L/D
akka-uct	21	✅ 10381 ms (7 iters)	✅ 10543 ms (7 iters)	≈ +1.6% (±19.2%)	— / —
akka-uct	25	✅ 8848 ms (8 iters)	✅ 8978 ms (8 iters)	≈ +1.5% (±20%)	— / —
finagle-chirper	21	✅ 6063 ms (11 iters)	✅ 6089 ms (11 iters)	≈ +0.4% (±46%)	⚠️ W:1 / ⚠️ W:1
finagle-chirper	25	✅ 5362 ms (12 iters)	✅ 5480 ms (12 iters)	≈ +2.2% (±44.8%)	⚠️ W:1 / ⚠️ W:1
fj-kmeans	21	✅ 2804 ms (22 iters)	✅ 2798 ms (22 iters)	≈ -0.2% (±4.3%)	— / —
fj-kmeans	25	✅ 2803 ms (22 iters)	✅ 2816 ms (22 iters)	≈ +0.5% (±5%)	— / —
future-genetic	21	✅ 2051 ms (30 iters)	✅ 2111 ms (29 iters)	≈ +2.9% (±4.7%)	— / —
future-genetic	25	✅ 1913 ms (32 iters)	✅ 2054 ms (30 iters)	🔴 +7.4%	— / —
naive-bayes	21	✅ 1264 ms (45 iters)	✅ 1392 ms (42 iters)	≈ +10.1% (±57.6%)	— / —
naive-bayes	25	✅ 1022 ms (56 iters)	✅ 1001 ms (57 iters)	≈ -2.1% (±54.8%)	— / —
reactors	21	✅ 16918 ms (5 iters)	✅ 15700 ms (5 iters)	≈ -7.2% (±13.6%)	— / —
reactors	25	✅ 17266 ms (5 iters)	✅ 18553 ms (5 iters)	🔴 +7.5%	— / —

Internal counter details (ddprof)

ddprof internal counters, latest / dev (✅ = 0, · = unavailable):

Benchmark	JDK	Dropped rec	Dropped jvmti	Dropped trace	Skipped WC	AGCT fail	Unwind fail
akka-uct	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
akka-uct	25	✅ / ✅	✅ / ✅	3 / 1	2366 / 2335	✅ / ✅	✅ / ✅
finagle-chirper	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
finagle-chirper	25	✅ / ✅	✅ / ✅	1 / 1	8231 / 8310	✅ / ✅	✅ / ✅
fj-kmeans	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
fj-kmeans	25	✅ / ✅	✅ / ✅	✅ / 3	1267 / 1209	✅ / ✅	✅ / ✅
future-genetic	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
future-genetic	25	✅ / ✅	✅ / ✅	2 / 1	2825 / 2902	✅ / ✅	✅ / ✅
naive-bayes	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
naive-bayes	25	✅ / ✅	✅ / ✅	2 / 3	3501 / 3486	✅ / ✅	✅ / ✅
reactors	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
reactors	25	✅ / ✅	✅ / ✅	1 / 1	1730 / 1894	✅ / ✅	✅ / ✅

dd-octo-sts · 2026-07-03T09:44:24Z

Benchmark Results (commit `821cac8`)

Pipeline: https://gitlab.ddbuild.io/DataDog/apm-reliability/benchmarking-platform/-/pipelines/122545771 Commit: 821cac8d91257bcc5696ccc715f1d9009a8e5432

✅ Within expected boundaries

No significant runtime deltas (all within run-to-run noise) and no internal-counter outliers.

Runtime details (per benchmark × JDK)

Benchmark	JDK	Latest	Dev	Δ (dev vs latest)	Issues L/D
akka-uct	21	✅ 10354 ms (7 iters)	✅ 10195 ms (7 iters)	≈ -1.5% (±19.7%)	— / —
akka-uct	25	✅ 8940 ms (8 iters)	✅ 8943 ms (8 iters)	≈ +0% (±20.2%)	— / —
finagle-chirper	21	✅ 6057 ms (11 iters)	✅ 6114 ms (11 iters)	≈ +0.9% (±46.1%)	⚠️ W:1 / ⚠️ W:1
finagle-chirper	25	✅ 5430 ms (12 iters)	✅ 5450 ms (12 iters)	≈ +0.4% (±44.3%)	⚠️ W:1 / ⚠️ W:1
fj-kmeans	21	✅ 2745 ms (23 iters)	✅ 2799 ms (22 iters)	≈ +2% (±4.3%)	— / —
fj-kmeans	25	✅ 2828 ms (22 iters)	✅ 2835 ms (22 iters)	≈ +0.2% (±4.8%)	— / —
future-genetic	21	✅ 2127 ms (29 iters)	✅ 2039 ms (30 iters)	≈ -4.1% (±4.5%)	— / —
future-genetic	25	✅ 2069 ms (30 iters)	✅ 2104 ms (30 iters)	≈ +1.7% (±4.4%)	— / —
naive-bayes	21	✅ 1227 ms (46 iters)	✅ 1221 ms (47 iters)	≈ -0.5% (±55.9%)	— / —
naive-bayes	25	✅ 1035 ms (55 iters)	✅ 1023 ms (56 iters)	≈ -1.2% (±55.7%)	— / —
reactors	21	✅ 17340 ms (5 iters)	✅ 17849 ms (5 iters)	≈ +2.9% (±14.2%)	— / —
reactors	25	✅ 18225 ms (5 iters)	✅ 17798 ms (5 iters)	≈ -2.3% (±6.9%)	— / —

Internal counter details (ddprof)

ddprof internal counters, latest / dev (✅ = 0, · = unavailable):

Benchmark	JDK	Dropped rec	Dropped jvmti	Dropped trace	Skipped WC	AGCT fail	Unwind fail
akka-uct	21	✅ / ✅	✅ / ✅	2 / ✅	2009 / ✅	✅ / ✅	✅ / ✅
akka-uct	25	✅ / ✅	✅ / ✅	1 / 1	2209 / 2322	✅ / ✅	✅ / ✅
finagle-chirper	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
finagle-chirper	25	✅ / ✅	✅ / ✅	1 / 2	8171 / 8480	✅ / ✅	✅ / ✅
fj-kmeans	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
fj-kmeans	25	✅ / ✅	✅ / ✅	3 / 2	1284 / 1225	✅ / ✅	✅ / ✅
future-genetic	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
future-genetic	25	✅ / ✅	✅ / ✅	✅ / 3	2928 / 2962	✅ / ✅	✅ / ✅
naive-bayes	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
naive-bayes	25	✅ / ✅	✅ / ✅	8 / 7	3490 / 3470	✅ / ✅	✅ / ✅
reactors	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
reactors	25	✅ / ✅	✅ / ✅	1 / 1	1835 / 1642	✅ / ✅	✅ / ✅

rkennke

Looks good to me (pending Jaroslav's Sphinx reviews)

dd-octo-sts · 2026-07-03T12:31:36Z

Benchmark Results (commit `bfdc687`)

Pipeline: https://gitlab.ddbuild.io/DataDog/apm-reliability/benchmarking-platform/-/pipelines/122570556 Commit: bfdc6877afabbdd6b921f29dd0dd584403621dc0

✅ Within expected boundaries

No significant runtime deltas (all within run-to-run noise) and no internal-counter outliers.

Runtime details (per benchmark × JDK)

Benchmark	JDK	Latest	Dev	Δ (dev vs latest)	Issues L/D
akka-uct	21	✅ 10564 ms (7 iters)	✅ 10428 ms (7 iters)	≈ -1.3% (±24.3%)	— / —
akka-uct	25	✅ 8887 ms (8 iters)	✅ 8873 ms (8 iters)	≈ -0.2% (±20%)	— / —
finagle-chirper	21	✅ 5982 ms (11 iters)	✅ 5942 ms (11 iters)	≈ -0.7% (±46%)	⚠️ W:1 / ⚠️ W:1
finagle-chirper	25	✅ 5370 ms (12 iters)	✅ 5503 ms (12 iters)	≈ +2.5% (±43%)	⚠️ W:1 / ⚠️ W:1
fj-kmeans	21	✅ 2821 ms (22 iters)	✅ 2827 ms (22 iters)	≈ +0.2% (±4.3%)	— / —
fj-kmeans	25	✅ 2821 ms (22 iters)	✅ 2832 ms (22 iters)	≈ +0.4% (±4.6%)	— / —
future-genetic	21	✅ 2027 ms (31 iters)	✅ 2098 ms (30 iters)	≈ +3.5% (±4.6%)	— / —
future-genetic	25	✅ 2060 ms (30 iters)	✅ 2123 ms (29 iters)	≈ +3.1% (±4.9%)	— / —
naive-bayes	21	✅ 1226 ms (46 iters)	✅ 1231 ms (46 iters)	≈ +0.4% (±57.4%)	— / —
naive-bayes	25	✅ 1011 ms (56 iters)	✅ 1018 ms (56 iters)	≈ +0.7% (±55.8%)	— / —
reactors	21	✅ 15812 ms (5 iters)	✅ 16153 ms (5 iters)	≈ +2.2% (±12.7%)	— / —
reactors	25	✅ 18260 ms (5 iters)	✅ 18464 ms (5 iters)	≈ +1.1% (±2.2%)	— / —

Internal counter details (ddprof)

ddprof internal counters, latest / dev (✅ = 0, · = unavailable):

Benchmark	JDK	Dropped rec	Dropped jvmti	Dropped trace	Skipped WC	AGCT fail	Unwind fail
akka-uct	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
akka-uct	25	✅ / ✅	✅ / ✅	4 / 4	2015 / 2290	✅ / ✅	✅ / ✅
finagle-chirper	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
finagle-chirper	25	✅ / ✅	✅ / ✅	1 / 2	8052 / 8333	✅ / ✅	✅ / ✅
fj-kmeans	21	✅ / ✅	✅ / ✅	✅ / ✅	1283 / ✅	✅ / ✅	✅ / ✅
fj-kmeans	25	✅ / ✅	✅ / ✅	5 / 3	1263 / 1279	✅ / ✅	✅ / ✅
future-genetic	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
future-genetic	25	✅ / ✅	✅ / ✅	1 / 1	2908 / 2905	✅ / ✅	✅ / ✅
naive-bayes	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
naive-bayes	25	✅ / ✅	✅ / ✅	2 / 13	3510 / 3498	✅ / ✅	✅ / ✅
reactors	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
reactors	25	✅ / ✅	✅ / ✅	2 / 1	1855 / 1720	✅ / ✅	✅ / ✅

…ample_id from MethodSample

dd-octo-sts · 2026-07-03T14:24:46Z

Benchmark Results (commit `b2d5245`)

Pipeline: https://gitlab.ddbuild.io/DataDog/apm-reliability/benchmarking-platform/-/pipelines/122598460 Commit: b2d524527f497eed49e0abd8c2bf4249ac2575b1

⚠️ Significant outliers

🟢 future-genetic (JDK 21): runtime -5.4% (2210→2091 ms)

Runtime details (per benchmark × JDK)

Benchmark	JDK	Latest	Dev	Δ (dev vs latest)	Issues L/D
akka-uct	21	✅ 10094 ms (7 iters)	✅ 10356 ms (7 iters)	≈ +2.6% (±21.2%)	— / —
akka-uct	25	✅ 8837 ms (8 iters)	✅ 8743 ms (8 iters)	≈ -1.1% (±22.7%)	— / —
finagle-chirper	21	✅ 5853 ms (11 iters)	✅ 5910 ms (11 iters)	≈ +1% (±43.6%)	⚠️ W:1 / ⚠️ W:1
finagle-chirper	25	✅ 5478 ms (12 iters)	✅ 5368 ms (12 iters)	≈ -2% (±44%)	⚠️ W:1 / ⚠️ W:1
fj-kmeans	21	✅ 2824 ms (22 iters)	✅ 2834 ms (22 iters)	≈ +0.4% (±4.8%)	— / —
fj-kmeans	25	✅ 2817 ms (22 iters)	✅ 2840 ms (22 iters)	≈ +0.8% (±4.8%)	— / —
future-genetic	21	✅ 2210 ms (28 iters)	✅ 2091 ms (30 iters)	🟢 -5.4%	— / —
future-genetic	25	✅ 1923 ms (32 iters)	✅ 1931 ms (32 iters)	≈ +0.4% (±4.8%)	— / —
naive-bayes	21	✅ 1260 ms (45 iters)	✅ 1229 ms (46 iters)	≈ -2.5% (±56.9%)	— / —
naive-bayes	25	✅ 1016 ms (56 iters)	✅ 1020 ms (56 iters)	≈ +0.4% (±56.3%)	— / —
reactors	21	✅ 17030 ms (5 iters)	✅ 17150 ms (5 iters)	≈ +0.7% (±12.4%)	— / —
reactors	25	✅ 18323 ms (5 iters)	✅ 18162 ms (5 iters)	≈ -0.9% (±3.7%)	— / —

Internal counter details (ddprof)

ddprof internal counters, latest / dev (✅ = 0, · = unavailable):

Benchmark	JDK	Dropped rec	Dropped jvmti	Dropped trace	Skipped WC	AGCT fail	Unwind fail
akka-uct	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
akka-uct	25	✅ / ✅	✅ / ✅	4 / 4	2267 / 2432	✅ / ✅	✅ / ✅
finagle-chirper	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
finagle-chirper	25	✅ / ✅	✅ / ✅	2 / 2	8669 / 8358	✅ / ✅	✅ / ✅
fj-kmeans	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
fj-kmeans	25	✅ / ✅	✅ / ✅	2 / 4	1268 / 1225	✅ / ✅	✅ / ✅
future-genetic	21	✅ / ✅	✅ / ✅	7 / ✅	3051 / ✅	✅ / ✅	✅ / ✅
future-genetic	25	✅ / ✅	✅ / ✅	1 / 1	2773 / 2068	✅ / ✅	✅ / ✅
naive-bayes	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
naive-bayes	25	✅ / ✅	✅ / ✅	7 / 6	3483 / 3500	✅ / ✅	✅ / ✅
reactors	21	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅	✅ / ✅
reactors	25	✅ / ✅	✅ / ✅	✅ / 4	1846 / 1692	✅ / ✅	✅ / ✅

jbachorik · 2026-07-09T11:57:06Z

@copilot resolve the merge conflicts in this pull request

Copilot · 2026-07-09T12:07:09Z

@copilot resolve the merge conflicts in this pull request

Resolved. I merged origin/main into this branch and fixed the conflict in ddprof-lib/src/main/cpp/vmEntry.cpp in commit 38362a03.

jbachorik

I did review ~50% of the code but I will need to get more info on some design decisions before I continue because things might change depending on that info.

jbachorik · 2026-07-09T12:40:06Z

  ExecutionMode _execution_mode;
  u64 _weight;
-  u32 _call_trace_id;
+  u64 _call_trace_id;


Uff. Nice catch.

jbachorik · 2026-07-09T12:43:07Z

+  u64 _end;
+  u64 _blocker;
+  u64 _unblockingSpanId;
+  Context _ctx;


I don't think you need to carry context here.
IIUC, this event would be written at the moment a thread is ublocked. At that point its context is valid and can be retrieved and written along this event.

jbachorik · 2026-07-09T12:45:38Z

+  u64 _unblockingSpanId;
+  Context _ctx;
+  u64 _callTraceId;
+  u64 _correlationId;


I think we discussed this already (or maybe it was another place?).
For the current work the correlation ID adds only overhead. The event will capture the correct stacktrace when it is written - if the implementation is correct, the event stacktrace should be exactly the same as the one that it would get by the correlation id.
So, it would be mostly just an overhead per TaskBlockEvent

jbachorik · 2026-07-09T12:59:37Z

+    JNIEnv *env, jclass unused, jboolean delegateMonitorEvents, jboolean wallPrecheck) {
  // JavaVM* has already been stored when the native library was loaded so we can pass nullptr here
-  return VM::initProfilerBridge(nullptr, true);
+  return VM::initProfilerBridge(nullptr, true, delegateMonitorEvents, wallPrecheck);


Historically, these engine specific settings would have been passed by an argument (via arguments.cpp)
I am a bit worried by introducing an alternative way of doing that here - also, the args are not engine agnostic so they kind of mix concerns here.
Could you take a look how to convert this to an arg that can be passed to the agent?

jbachorik · 2026-07-09T13:12:35Z

+  inline bool parkEnter(u64 start_ticks) {
+    u32 flags = __atomic_load_n(&_misc_flags, __ATOMIC_ACQUIRE);
+    while ((flags & FLAG_PARKED) == 0) {
+      _park_context = ContextApi::snapshot();


I don't think we need to capture the context here. The event will be written at appropriate parkExit and since the thread is parking, there is no way the context would change.

jbachorik · 2026-07-09T13:28:02Z

+  // Virtual-thread path: span/root ids captured at block entry are passed explicitly because
+  // the native OTEP TLS is carrier-scoped and cannot be trusted. Custom attributes not propagated.
+  Context ctx{(u64)spanId, (u64)rootSpanId};
+  return recordTaskBlockWithContextIfEligible(tid, (u64)startTicks, (u64)endTicks,


Is this still true? We did a bunch of fixes in the context area and I think this might be redundant as we should always get correct context when we ask for it from the same thread.

jbachorik · 2026-07-09T13:47:26Z

+extern "C" DLLEXPORT void JNICALL
+Java_com_datadoghq_profiler_JavaProfiler_blockExitWithSnapshot0(
+    JNIEnv *env, jclass unused, jlong token, jlongArray snapshotArray) {
+  BlockRunSnapshot snapshot{};
+  snapshot.active_state = OSThreadState::UNKNOWN;
+  snapshot.sampled_state = OSThreadState::UNKNOWN;
+  snapshot.owner = BlockRunOwner::NONE;
+  if (snapshotAndExitBlockedRun(token, &snapshot)) {
+    writeBlockRunSnapshot(env, snapshotArray, &snapshot);
+  } else {
+    writeBlockRunSnapshot(env, snapshotArray, nullptr);
  }
-  ThreadFilter::SlotID slot_id = ThreadFilter::tokenSlotId(block_token);
-  if (current->filterSlotId() != slot_id) {
-    return;
+}
+
+extern "C" DLLEXPORT jboolean JNICALL
+Java_com_datadoghq_profiler_JavaProfiler_recordTaskBlock0(
+    JNIEnv *env, jclass unused, jlong startTicks, jlong endTicks,
+    jlong blocker, jlong unblockingSpanId) {
+  int tid = ProfiledThread::currentTid();
+  if (tid < 0) {
+    return JNI_FALSE;
  }
-  ThreadFilter *tf = Profiler::instance()->threadFilter();
-  if (tf->enabled()) {
-    tf->exitBlockedRun(slot_id, ThreadFilter::tokenGeneration(block_token));
+  // Context (span ids + tags) is captured from OTEP TLS via ContextApi::snapshot()
+  // inside recordTaskBlockLiveIfEligible, mirroring the recordQueueTime convention.
+  return recordTaskBlockLiveIfEligible(tid, (u64)startTicks, (u64)endTicks,
+                                       (u64)blocker, (u64)unblockingSpanId)
+             ? JNI_TRUE
+             : JNI_FALSE;
+}
+
+extern "C" DLLEXPORT jboolean JNICALL
+Java_com_datadoghq_profiler_JavaProfiler_recordTaskBlockWithContext0(
+    JNIEnv *env, jclass unused, jlong startTicks, jlong endTicks,
+    jlong blocker, jlong unblockingSpanId,
+    jlong spanId, jlong rootSpanId) {
+  int tid = ProfiledThread::currentTid();
+  if (tid < 0) {
+    return JNI_FALSE;
  }
+  // Virtual-thread path: span/root ids captured at block entry are passed explicitly because


I will need some explanation about why we need to snapshot the context - are we deferring writing related events way after they were collected?

jbachorik · 2026-07-09T13:50:55Z

+
+#if defined(__linux__)
+
+class NativeFdClassifier {


Could you add some comment block here about what the classification spec is?

jbachorik · 2026-07-09T13:52:36Z

+  });
+}
+
+ssize_t NativeSocketInterposer::write_hook(int fd, const void* buf, size_t len) {


Sounds good, thanks! Can we get some benchmark numbers to get the feeling about what kind of overhead we are talking here?

jbachorik · 2026-07-09T14:08:58Z

+bool Profiler::recordTaskBlockAsync(int tid, TaskBlockEvent *event) {
+  if (!_task_block_drain_running.load(std::memory_order_acquire)) {
+    Counters::increment(TASK_BLOCK_QUEUE_DROPPED);
+    return false;
+  }
+
+  QueuedTaskBlockEvent queued;
+  queued.tid = tid;
+  queued.generation = _task_block_generation.load(std::memory_order_acquire);
+  queued.event = *event;
+  if (!_task_block_queue.tryPush(queued)) {
+    Counters::increment(TASK_BLOCK_QUEUE_DROPPED);
+    return false;
+  }
+  return true;
+}
+


I will need also some info why we must record those events asynchronously - I see this used only from monitor exit and fd interposer; both places do not seem like we could not record the event synchronously.
Could you put some explanations either to the PR description or even on the related classes, why we need this asynchronous machinery?

kaahos added 11 commits May 28, 2026 15:28

feat: wall-clock precheck and signal suppression

1045a85

Merge branch 'main' into paul.fournillon/wallclock-suppression

aed7b1a

fix

7a250b6

Merge branch 'main' into paul.fournillon/wallclock-suppression

6028fdd

fix: fix build + tests

1e1bcd1

fix: fix mem leaks in tests

b1cb73f

fix: track wall precheck block state in thread filter

a3a9462

fix: arm wall precheck after recording sample

137065c

fix: include wait states in wall precheck suppression

c7caa46

Fix ProfiledThread ownership in park_state_ut

55073d0

Add Java block-state bridge for wall-clock precheck

619449a

Fix wall-clock thread filter reset

1cd0f8b

kaahos force-pushed the paul.fournillon/wallclock-taskblock branch from bcf3c2b to a46d368 Compare June 2, 2026 08:24

Gate wall-clock precheck on untraced context

3ee7f42

kaahos force-pushed the paul.fournillon/wallclock-taskblock branch 3 times, most recently from 3f2f71a to d1e3210 Compare June 3, 2026 13:00

Copilot started work on behalf of kaahos June 3, 2026 13:21 View session

Copilot finished work on behalf of kaahos June 3, 2026 13:27

kaahos marked this pull request as ready for review June 3, 2026 13:40

kaahos requested a review from a team as a code owner June 3, 2026 13:40

chatgpt-codex-connector Bot reviewed Jun 3, 2026

View reviewed changes

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

kaahos force-pushed the paul.fournillon/wallclock-taskblock branch 2 times, most recently from 2101007 to a94677a Compare June 3, 2026 14:05

Merge branch 'main' into paul.fournillon/wallclock-suppression

6bda356

kaahos force-pushed the paul.fournillon/wallclock-taskblock branch from a94677a to 681582c Compare June 3, 2026 14:38

jbachorik added the sphinx:critical Sphinx: critical — human review required label Jun 30, 2026

Merge branch 'main' into paul.fournillon/wallclock-taskblock

b7db495

Merge branch 'main' into paul.fournillon/wallclock-taskblock

36f3db5

kaahos added 5 commits July 3, 2026 11:02

fix: fix errno preservation in native socket hook

326dcc2

fix: fix deferred TaskBlock span context argument order

439aacd

fix: clarify JavaProfiler init API behavior

b2084d9

fix: refactor fd cache system

e09112d

fix: fix memory issue in nativeSocketInterposer_ut.cpp

821cac8

Merge branch 'main' into paul.fournillon/wallclock-taskblock

bfdc687

kaahos requested review from jbachorik and rkennke July 3, 2026 12:05

rkennke approved these changes Jul 3, 2026

View reviewed changes

kaahos and others added 2 commits July 3, 2026 15:51

Merge branch 'main' into paul.fournillon/wallclock-taskblock

bb79ff4

fix: remove useless fields (correlation_id from ExecutionEvent and _s…

b2d5245

…ample_id from MethodSample

kaahos mentioned this pull request Jul 6, 2026

Add wallclock TaskBlock profiler support DataDog/dd-trace-java#11544

Draft

kaahos and others added 2 commits July 7, 2026 17:31

Merge branch 'main' into paul.fournillon/wallclock-taskblock

0af6e60

Merge branch 'main' into paul.fournillon/wallclock-taskblock

b6f846a

Copilot started work on behalf of jbachorik July 9, 2026 11:57 View session

Merge origin/main and resolve vmEntry include conflict

38362a0

Copilot finished work on behalf of jbachorik July 9, 2026 12:07

jbachorik requested changes Jul 9, 2026

View reviewed changes


		#if defined(__linux__)

		class NativeFdClassifier {

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Benchmark Results (commit `36f3db5`)

Benchmark Results (commit `821cac8`)

Benchmark Results (commit `bfdc687`)

Benchmark Results (commit `b2d5245`)