feat(wall): support signal suppression for unfiltered threads by kaahos · Pull Request #663 · DataDog/java-profiler · GitHub

What does this PR do?:

Extends wall-clock signal suppression to threads sampled through the existing explicit filter= mode.

When wall profiling runs with both filter= and wallprecheck=true, the profiler now:

Tracks thread identity and lifecycle independently from context-filter membership.
Registers Java threads that already exist when profiling starts.
Registers new threads through the existing thread lifecycle callbacks.
Allows block and park hooks to lazily associate pre-existing threads with their registry slots.
Makes the thread metadata available to both the ASGCT and JVMTI wall-clock paths.
Suppresses repeated samples only for profiler-owned blocking runs that remain outside the context window.
Validates thread identity, slot lifecycle, and context transitions before applying suppression.

The existing context-filtered behavior remains unchanged. This PR does not change the meaning of filter=.

Motivation:

With filter=, wall-clock profiling already samples every thread. However, threads outside an active context did not have the lifecycle metadata required to recognize and suppress repeated samples from the same profiler-owned blocking run.

This change closes that metadata gap. It also provides the thread lifecycle machinery needed by the follow-up TaskBlock work for non-context threads.

Implementation notes:

Thread identity is indexed by native TID while context-window membership remains separate.
Lifecycle generations prevent reused slots or TIDs from inheriting stale state.
Context-window epochs prevent suppression if a thread enters or leaves a context during a blocking run.
Registry tracking is activated only for wall recordings using explicit filter= together with wallprecheck=true.
Tracking is disabled again when wall profiling is absent, precheck is disabled, wall startup fails, or a later recording uses another configuration.
Both ASGCT and JVMTI wall-clock collection paths use the same registry validation.

How to test the change?:

./.claude/commands/build-and-summarize :ddprof-lib:gtestDebug_threadFilter_ut :ddprof-lib:gtestDebug_wallprecheck_args_ut
./.claude/commands/build-and-summarize :ddprof-test:testDebug -Ptests="*UnfilteredWallPrecheck*"
./.claude/commands/build-and-summarize testDebug

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 security review.
This PR doesn't touch any of that.
JIRA: [JIRA-XXXX]

CI Test Results

Run: #32491259439 | Commit: 96c1a29 | Duration: 15m 9s (longest job)

❌ 1 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-amd64/debug / 17-librca

Job: View logs

No detailed failure information available. Check the job logs.

Summary: Total: 32 | Passed: 31 | Failed: 1

Updated: 2026-08-21 14:34:40 UTC

Benchmark Results (commit fb1c44d)

Pipeline: https://gitlab.ddbuild.io/DataDog/apm-reliability/benchmarking-platform/-/pipelines/125547869 Commit: fb1c44de77197780eae60267ff98bd38a907a558

⚠️ Significant outliers

🔴 fj-kmeans (JDK 21): runtime +5.9% (2679→2836 ms)
🔴 future-genetic (JDK 21): runtime +3.8% (2083→2162 ms)

Runtime details (per benchmark × JDK)

Benchmark	JDK	Latest	Dev	Δ (dev vs latest)	Issues L/D
akka-uct	21	✅ 10210 ms (21 iters)	✅ 10256 ms (21 iters)	≈ +0.5% (±10.9%)	— / —
akka-uct	25	✅ 8953 ms (24 iters)	✅ 8890 ms (24 iters)	≈ -0.7% (±10.2%)	— / —
finagle-chirper	21	✅ 6000 ms (33 iters)	✅ 5960 ms (33 iters)	≈ -0.7% (±25.4%)	⚠️ W:3 / ⚠️ W:3
finagle-chirper	25	✅ 5431 ms (36 iters)	✅ 5443 ms (36 iters)	≈ +0.2% (±24.6%)	⚠️ W:4 / ⚠️ W:3
fj-kmeans	21	✅ 2679 ms (70 iters)	✅ 2836 ms (66 iters)	🔴 +5.9%	— / —
fj-kmeans	25	✅ 2847 ms (66 iters)	✅ 2828 ms (66 iters)	≈ -0.7% (±2.6%)	— / —
future-genetic	21	✅ 2083 ms (89 iters)	✅ 2162 ms (86 iters)	🔴 +3.8%	— / —
future-genetic	25	✅ 2076 ms (90 iters)	✅ 2122 ms (88 iters)	≈ +2.2% (±2.5%)	— / —
naive-bayes	21	✅ 1252 ms (136 iters)	✅ 1248 ms (137 iters)	≈ -0.3% (±32.7%)	— / —
naive-bayes	25	✅ 1008 ms (170 iters)	✅ 1023 ms (167 iters)	≈ +1.5% (±31.7%)	— / —
reactors	21	✅ 16312 ms (15 iters)	✅ 16357 ms (15 iters)	≈ +0.3% (±8.8%)	— / —
reactors	25	✅ 18416 ms (15 iters)	✅ 18780 ms (15 iters)	≈ +2% (±3.6%)	— / —

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 / ✅	1891 / 2004	✅ / ✅	✅ / ✅
akka-uct	25	✅ / ✅	✅ / ✅	1 / 1	2305 / 2283	✅ / ✅	✅ / ✅
finagle-chirper	21	✅ / ✅	✅ / ✅	4 / 2	8183 / 8674	✅ / ✅	✅ / ✅
finagle-chirper	25	✅ / ✅	✅ / ✅	✅ / ✅	8087 / 8641	✅ / ✅	✅ / ✅
fj-kmeans	21	✅ / ✅	✅ / ✅	2 / 2	1270 / 1278	✅ / ✅	✅ / ✅
fj-kmeans	25	✅ / ✅	✅ / ✅	3 / 3	1282 / 1275	✅ / ✅	✅ / ✅
future-genetic	21	✅ / ✅	✅ / ✅	1 / 3	2966 / 3007	✅ / ✅	✅ / ✅
future-genetic	25	✅ / ✅	✅ / ✅	2 / ✅	2992 / 2972	✅ / ✅	✅ / ✅
naive-bayes	21	✅ / ✅	✅ / ✅	3 / 6	3491 / 3501	✅ / ✅	✅ / ✅
naive-bayes	25	✅ / ✅	✅ / ✅	1 / 5	3488 / 3493	✅ / ✅	✅ / ✅
reactors	21	✅ / ✅	✅ / ✅	2 / ✅	1711 / 1786	✅ / ✅	✅ / ✅
reactors	25	✅ / ✅	✅ / ✅	✅ / ✅	1819 / 1920	✅ / ✅	✅ / ✅

Benchmark Results (commit 1118f62)

Pipeline: https://gitlab.ddbuild.io/DataDog/apm-reliability/benchmarking-platform/-/pipelines/125554643 Commit: 1118f62831a4384bdf0283ef01a626c5bdc48af5

⚠️ Significant outliers

🟢 fj-kmeans (JDK 21): runtime -3.9% (2808→2698 ms)
🟢 future-genetic (JDK 25): runtime -4.2% (2088→2001 ms)

Runtime details (per benchmark × JDK)

Benchmark	JDK	Latest	Dev	Δ (dev vs latest)	Issues L/D
akka-uct	21	✅ 10294 ms (21 iters)	✅ 10251 ms (21 iters)	≈ -0.4% (±11.4%)	— / —
akka-uct	25	✅ 8933 ms (24 iters)	✅ 8835 ms (24 iters)	≈ -1.1% (±10%)	— / —
finagle-chirper	21	✅ 6016 ms (33 iters)	✅ 6034 ms (33 iters)	≈ +0.3% (±25.3%)	⚠️ W:3 / ⚠️ W:3
finagle-chirper	25	✅ 5462 ms (36 iters)	✅ 5452 ms (36 iters)	≈ -0.2% (±24.6%)	⚠️ W:3 / ⚠️ W:3
fj-kmeans	21	✅ 2808 ms (66 iters)	✅ 2698 ms (70 iters)	🟢 -3.9%	— / —
fj-kmeans	25	✅ 2812 ms (66 iters)	✅ 2813 ms (66 iters)	≈ +0% (±2.6%)	— / —
future-genetic	21	✅ 2067 ms (90 iters)	✅ 2083 ms (90 iters)	≈ +0.8% (±2.7%)	— / —
future-genetic	25	✅ 2088 ms (89 iters)	✅ 2001 ms (93 iters)	🟢 -4.2%	— / —
naive-bayes	21	✅ 1239 ms (138 iters)	✅ 1231 ms (138 iters)	≈ -0.6% (±32.7%)	— / —
naive-bayes	25	✅ 1019 ms (168 iters)	✅ 1011 ms (169 iters)	≈ -0.8% (±32.1%)	— / —
reactors	21	✅ 16149 ms (15 iters)	✅ 16215 ms (15 iters)	≈ +0.4% (±8.4%)	— / —
reactors	25	✅ 18598 ms (15 iters)	✅ 18345 ms (15 iters)	≈ -1.4% (±5.1%)	— / —

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 / 2	1978 / 1973	✅ / ✅	✅ / ✅
akka-uct	25	✅ / ✅	✅ / ✅	2 / ✅	2287 / 2449	✅ / ✅	✅ / ✅
finagle-chirper	21	✅ / ✅	✅ / ✅	2 / 2	8978 / 8724	✅ / ✅	✅ / ✅
finagle-chirper	25	✅ / ✅	✅ / ✅	✅ / ✅	8633 / 8297	✅ / ✅	✅ / ✅
fj-kmeans	21	✅ / ✅	✅ / ✅	2 / 1	1257 / 1281	✅ / ✅	✅ / ✅
fj-kmeans	25	✅ / ✅	✅ / ✅	1 / 4	1280 / 1268	✅ / ✅	✅ / ✅
future-genetic	21	✅ / ✅	✅ / ✅	✅ / 3	2909 / 2923	✅ / ✅	✅ / ✅
future-genetic	25	✅ / ✅	✅ / ✅	2 / 5	2847 / 2887	✅ / ✅	✅ / ✅
naive-bayes	21	✅ / ✅	✅ / ✅	7 / 4	3492 / 3493	✅ / ✅	✅ / ✅
naive-bayes	25	✅ / ✅	✅ / ✅	4 / 2	3463 / 3473	✅ / ✅	✅ / ✅
reactors	21	✅ / ✅	✅ / ✅	✅ / 1	1761 / 1721	✅ / ✅	✅ / ✅
reactors	25	✅ / ✅	✅ / ✅	✅ / ✅	1916 / 1880	✅ / ✅	✅ / ✅

Benchmark Results (commit 40dbe8e)

Pipeline: https://gitlab.ddbuild.io/DataDog/apm-reliability/benchmarking-platform/-/pipelines/125596529 Commit: 40dbe8e833888192b6026558590bce1cf0ad1c9f

⚠️ Significant outliers

🟢 fj-kmeans (JDK 21): runtime -2.7% (2823→2748 ms)
🔴 future-genetic (JDK 21): runtime +4.1% (2041→2125 ms)
🔴 future-genetic (JDK 25): runtime +5.8% (1994→2110 ms)

Runtime details (per benchmark × JDK)

Benchmark	JDK	Latest	Dev	Δ (dev vs latest)	Issues L/D
akka-uct	21	✅ 10340 ms (21 iters)	✅ 10312 ms (21 iters)	≈ -0.3% (±11.6%)	— / —
akka-uct	25	✅ 8871 ms (24 iters)	✅ 8849 ms (24 iters)	≈ -0.2% (±10.1%)	— / —
finagle-chirper	21	✅ 6017 ms (33 iters)	✅ 6015 ms (33 iters)	≈ -0% (±25%)	⚠️ W:3 / ⚠️ W:4
finagle-chirper	25	✅ 5470 ms (36 iters)	✅ 5509 ms (36 iters)	≈ +0.7% (±24.2%)	⚠️ W:4 / ⚠️ W:3
fj-kmeans	21	✅ 2823 ms (66 iters)	✅ 2748 ms (68 iters)	🟢 -2.7%	— / —
fj-kmeans	25	✅ 2856 ms (66 iters)	✅ 2847 ms (66 iters)	≈ -0.3% (±2.6%)	— / —
future-genetic	21	✅ 2041 ms (90 iters)	✅ 2125 ms (88 iters)	🔴 +4.1%	— / —
future-genetic	25	✅ 1994 ms (93 iters)	✅ 2110 ms (88 iters)	🔴 +5.8%	— / —
naive-bayes	21	✅ 1247 ms (137 iters)	✅ 1259 ms (135 iters)	≈ +1% (±33.5%)	— / —
naive-bayes	25	✅ 1027 ms (167 iters)	✅ 1018 ms (168 iters)	≈ -0.9% (±31.5%)	— / —
reactors	21	✅ 16583 ms (15 iters)	✅ 16798 ms (15 iters)	≈ +1.3% (±7.5%)	— / —
reactors	25	✅ 18582 ms (15 iters)	✅ 18610 ms (15 iters)	≈ +0.2% (±5.1%)	— / —

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	✅ / ✅	✅ / ✅	✅ / 6	1978 / 1998	✅ / ✅	✅ / ✅
akka-uct	25	✅ / ✅	✅ / ✅	✅ / 1	2344 / 2271	✅ / ✅	✅ / ✅
finagle-chirper	21	✅ / ✅	✅ / ✅	2 / 2	8863 / 8312	✅ / ✅	✅ / ✅
finagle-chirper	25	✅ / ✅	✅ / ✅	1 / ✅	8368 / 8738	✅ / ✅	✅ / ✅
fj-kmeans	21	✅ / ✅	✅ / ✅	7 / 1	1284 / 1242	✅ / ✅	✅ / ✅
fj-kmeans	25	✅ / ✅	✅ / ✅	1 / 4	1302 / 1289	✅ / ✅	✅ / ✅
future-genetic	21	✅ / ✅	✅ / ✅	1 / 1	2979 / 2980	✅ / ✅	✅ / ✅
future-genetic	25	✅ / ✅	✅ / ✅	✅ / ✅	2847 / 2862	✅ / ✅	✅ / ✅
naive-bayes	21	✅ / ✅	✅ / ✅	4 / 5	3520 / 3534	✅ / ✅	✅ / ✅
naive-bayes	25	✅ / ✅	✅ / ✅	3 / 3	3523 / 3509	✅ / ✅	✅ / ✅
reactors	21	✅ / ✅	✅ / ✅	2 / 2	1682 / 1809	✅ / ✅	✅ / ✅
reactors	25	✅ / ✅	✅ / ✅	2 / ✅	1806 / 1871	✅ / ✅	✅ / ✅

Pull request overview

Extends wall-clock “owned-block” signal suppression to unfiltered (explicit filter=) wall recordings when wallprecheck=true, by introducing a thread registry keyed by native TID and integrating it into both ASGCT and JVMTI wall-clock sampling paths.

Changes:

Added unfiltered wall thread registry support (native TID indexing, lifecycle generations, recording epochs) and wired it into profiler lifecycle + wall-clock precheck logic.
Added a bounded candidate-selection/backfill mechanism for precheck to avoid reverting to O(N) registry work per wall tick under heavy suppression.
Added Java integration tests, C++ unit tests, and a JMH benchmark to validate behavior and measure overhead.

Reviewed changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
ddprof-test/src/test/java/com/datadoghq/profiler/wallclock/UnfilteredWallPrecheckTest.java	New integration coverage for suppression behavior in explicit-empty-filter wall recordings.
ddprof-test/src/test/java/com/datadoghq/profiler/wallclock/UnfilteredWallPrecheckRestartTest.java	Verifies registry activation does not leak across recording restarts and handles stopped gaps safely.
ddprof-test/src/test/java/com/datadoghq/profiler/wallclock/JvmtiBasedUnfilteredWallPrecheckTest.java	Ensures the unfiltered path works when wall sampling delegates stacks via JVMTI.
ddprof-test/src/test/java/com/datadoghq/profiler/wallclock/J9WallClockPrecheckCapabilityTest.java	Confirms J9 wall engine capability gating prevents activation of unfiltered tracking.
ddprof-test/src/test/java/com/datadoghq/profiler/AbstractProfilerTest.java	Adds beforeProfilerStart() hook to allow test setup before profiler thread callbacks are enabled.
ddprof-stresstest/src/jmh/java/com/datadoghq/profiler/WallClockPrecheckBenchmarkHooks.java	Exposes owned-block hooks to benchmarks without widening core API surface.
ddprof-stresstest/src/jmh/java/com/datadoghq/profiler/stresstest/scenarios/throughput/WallClockPrecheckOverheadBenchmark.java	Adds throughput benchmark comparing wallprecheck=false/true as owned-block population grows.
ddprof-lib/src/test/cpp/wallprecheck_args_ut.cpp	Adds capability tests and verifies explicit-empty vs omitted filter parsing behavior.
ddprof-lib/src/test/cpp/wallClockCandidateSelector_ut.cpp	Unit-tests the new bounded candidate selection logic.
ddprof-lib/src/test/cpp/threadFilter_ut.cpp	Expands tests for registry/epoch/lifecycle behavior and adjusts TID usage in recovery test.
ddprof-lib/src/main/cpp/wallClockCandidateSelector.h	Adds reusable “randomized prefix without replacement” candidate selection with stats.
ddprof-lib/src/main/cpp/wallClock.h	Integrates candidate selector and adds bounded-visit backfill path to the wall timer loop.
ddprof-lib/src/main/cpp/wallClock.cpp	Updates precheck suppression to validate registry identity + context transitions; supports lazy registry lookups.
ddprof-lib/src/main/cpp/threadFilter.h	Introduces registry state (TID index, epochs, lifecycle generation) and APIs for unfiltered tracking.
ddprof-lib/src/main/cpp/threadFilter.cpp	Implements lock-free lookups + mutex-serialized writers for TID indexing, epoch refresh, and retirement.
ddprof-lib/src/main/cpp/profiler.h	Declares bootstrap of existing Java threads for registry population.
ddprof-lib/src/main/cpp/profiler.cpp	Boots existing Java threads into registry when unfiltered tracking is active; deactivates registry on stop/failure.
ddprof-lib/src/main/cpp/jvmThread.h	Adds capability check for cross-thread native TID lookup support.
ddprof-lib/src/main/cpp/jvmThread.cpp	Implements native TID lookup support predicate.
ddprof-lib/src/main/cpp/javaApi.cpp	Ensures TLS slot binding is validated/refreshed before using owned-block and filter APIs.
ddprof-lib/src/main/cpp/engine.h	Adds wall-engine capability hook for unfiltered precheck support.
ddprof-lib/src/main/cpp/counters.h	Adds counters for registry bootstrap and bounded-lookup/backfill diagnostics.

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Benchmark Results (commit d82291f)

Pipeline: https://gitlab.ddbuild.io/DataDog/apm-reliability/benchmarking-platform/-/pipelines/125875202 Commit: d82291ff62852b63091350a05ebf26283fa39029

✅ 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	✅ 10141 ms (21 iters)	✅ 10278 ms (21 iters)	≈ +1.4% (±11.9%)	— / —
akka-uct	25	✅ 8800 ms (24 iters)	✅ 8939 ms (24 iters)	≈ +1.6% (±9.7%)	— / —
finagle-chirper	21	✅ 6003 ms (33 iters)	✅ 6060 ms (33 iters)	≈ +0.9% (±25.4%)	⚠️ W:3 / ⚠️ W:3
finagle-chirper	25	✅ 5463 ms (36 iters)	✅ 5482 ms (36 iters)	≈ +0.3% (±24.1%)	⚠️ W:3 / ⚠️ W:3
fj-kmeans	21	✅ 2780 ms (68 iters)	✅ 2771 ms (68 iters)	≈ -0.3% (±2.7%)	— / —
fj-kmeans	25	✅ 2752 ms (68 iters)	✅ 2824 ms (66 iters)	≈ +2.6% (±2.7%)	— / —
future-genetic	21	✅ 2082 ms (90 iters)	✅ 2035 ms (91 iters)	≈ -2.3% (±2.6%)	— / —
future-genetic	25	✅ 2101 ms (88 iters)	✅ 2055 ms (90 iters)	≈ -2.2% (±2.6%)	— / —
naive-bayes	21	✅ 1299 ms (132 iters)	✅ 1232 ms (138 iters)	≈ -5.2% (±31.7%)	— / —
naive-bayes	25	✅ 1011 ms (169 iters)	✅ 1013 ms (169 iters)	≈ +0.2% (±31.4%)	— / —
reactors	21	✅ 16511 ms (15 iters)	✅ 16445 ms (15 iters)	≈ -0.4% (±9.8%)	— / —
reactors	25	✅ 18516 ms (15 iters)	✅ 18146 ms (15 iters)	≈ -2% (±6.2%)	— / —

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	✅ / ✅	✅ / ✅	2 / 2	1925 / 1914	✅ / ✅	✅ / ✅
akka-uct	25	✅ / ✅	✅ / ✅	2 / 3	2117 / 2331	✅ / ✅	✅ / ✅
finagle-chirper	21	✅ / ✅	✅ / ✅	4 / 3	8401 / 8842	✅ / ✅	✅ / ✅
finagle-chirper	25	✅ / ✅	✅ / ✅	1 / 1	8557 / 8073	✅ / ✅	✅ / ✅
fj-kmeans	21	✅ / ✅	✅ / ✅	2 / 3	1243 / 1272	✅ / ✅	✅ / ✅
fj-kmeans	25	✅ / ✅	✅ / ✅	✅ / 1	1265 / 1283	✅ / ✅	✅ / ✅
future-genetic	21	✅ / ✅	✅ / ✅	3 / 1	3054 / 3036	✅ / ✅	✅ / ✅
future-genetic	25	✅ / ✅	✅ / ✅	✅ / 1	2890 / 2867	✅ / ✅	✅ / ✅
naive-bayes	21	✅ / ✅	✅ / ✅	4 / 3	3522 / 3464	✅ / ✅	✅ / ✅
naive-bayes	25	✅ / ✅	✅ / ✅	4 / 5	3452 / 3463	✅ / ✅	✅ / ✅
reactors	21	✅ / ✅	✅ / ✅	✅ / 2	1679 / 1552	✅ / ✅	✅ / ✅
reactors	25	✅ / ✅	✅ / ✅	✅ / ✅	1933 / 1805	✅ / ✅	✅ / ✅

Benchmark Results (commit ec76f58)

Pipeline: https://gitlab.ddbuild.io/DataDog/apm-reliability/benchmarking-platform/-/pipelines/125883187 Commit: ec76f5829d243f516dee70833f3dfbe7a2b9eaa3

⚠️ Significant outliers

🟢 fj-kmeans (JDK 21): runtime -4.1% (2839→2724 ms)
🔴 future-genetic (JDK 21): runtime +3% (2066→2127 ms)
🔴 future-genetic (JDK 25): runtime +5.8% (2006→2122 ms)

Runtime details (per benchmark × JDK)

Benchmark	JDK	Latest	Dev	Δ (dev vs latest)	Issues L/D
akka-uct	21	✅ 10350 ms (21 iters)	✅ 10305 ms (21 iters)	≈ -0.4% (±11.3%)	— / —
akka-uct	25	✅ 8864 ms (24 iters)	✅ 8976 ms (24 iters)	≈ +1.3% (±10.4%)	— / —
finagle-chirper	25	✅ 5472 ms (36 iters)	✅ 5418 ms (36 iters)	≈ -1% (±24.3%)	⚠️ W:3 / ⚠️ W:3
fj-kmeans	21	✅ 2839 ms (66 iters)	✅ 2724 ms (68 iters)	🟢 -4.1%	— / —
fj-kmeans	25	✅ 2851 ms (66 iters)	✅ 2836 ms (66 iters)	≈ -0.5% (±2.6%)	— / —
future-genetic	21	✅ 2066 ms (89 iters)	✅ 2127 ms (87 iters)	🔴 +3%	— / —
future-genetic	25	✅ 2006 ms (92 iters)	✅ 2122 ms (87 iters)	🔴 +5.8%	— / —
naive-bayes	21	✅ 1277 ms (134 iters)	✅ 1289 ms (133 iters)	≈ +0.9% (±32.4%)	— / —
naive-bayes	25	✅ 1021 ms (167 iters)	✅ 1023 ms (168 iters)	≈ +0.2% (±31.6%)	— / —
reactors	21	✅ 15903 ms (15 iters)	✅ 16452 ms (15 iters)	≈ +3.5% (±8.8%)	— / —
reactors	25	✅ 18032 ms (15 iters)	✅ 18628 ms (15 iters)	≈ +3.3% (±4.7%)	— / —

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	✅ / ✅	✅ / ✅	1 / 3	2089 / 2428	✅ / ✅	✅ / ✅
finagle-chirper	21	✅ / ✅	✅ / ✅	7 / 2	8520 / 8487	✅ / ✅	✅ / ✅
finagle-chirper	25	✅ / ✅	✅ / ✅	4 / 2	8382 / 8319	✅ / ✅	✅ / ✅
fj-kmeans	21	✅ / ✅	✅ / ✅	4 / 4	1278 / 1277	✅ / ✅	✅ / ✅
fj-kmeans	25	✅ / ✅	✅ / ✅	4 / ✅	1290 / 1289	✅ / ✅	✅ / ✅
future-genetic	21	✅ / ✅	✅ / ✅	3 / 2	2953 / 3032	✅ / ✅	✅ / ✅
future-genetic	25	✅ / ✅	✅ / ✅	2 / 2	2846 / 2856	✅ / ✅	✅ / ✅
naive-bayes	21	✅ / ✅	✅ / ✅	3 / 3	3534 / 3561	✅ / ✅	✅ / ✅
naive-bayes	25	✅ / ✅	✅ / ✅	1 / 3	3480 / 3510	✅ / ✅	✅ / ✅
reactors	21	✅ / ✅	✅ / ✅	1 / ✅	1614 / 1718	✅ / ✅	✅ / ✅
reactors	25	✅ / ✅	✅ / ✅	✅ / 3	1962 / 1876	✅ / ✅	✅ / ✅

Benchmark Results (commit 82e05b6)

Pipeline: https://gitlab.ddbuild.io/DataDog/apm-reliability/benchmarking-platform/-/pipelines/128529459 Commit: 82e05b6f02f2f64cd9a39e9a2791b4fb2388587e

⚠️ Significant outliers

🔴 future-genetic (JDK 21): runtime +3.9% (2061→2142 ms)

Runtime details (per benchmark × JDK)

Benchmark	JDK	Latest	Dev	Δ (dev vs latest)	Issues L/D
akka-uct	21	✅ 10220 ms (21 iters)	✅ 10147 ms (21 iters)	≈ -0.7% (±11%)	— / —
akka-uct	25	✅ 8860 ms (24 iters)	✅ 8828 ms (24 iters)	≈ -0.4% (±9.6%)	— / —
finagle-chirper	21	✅ 5958 ms (33 iters)	✅ 6066 ms (33 iters)	≈ +1.8% (±25.6%)	⚠️ W:3 / ⚠️ W:3
finagle-chirper	25	✅ 5534 ms (36 iters)	✅ 5457 ms (36 iters)	≈ -1.4% (±24.1%)	⚠️ W:3 / ⚠️ W:3
fj-kmeans	21	✅ 2724 ms (68 iters)	✅ 2731 ms (68 iters)	≈ +0.3% (±2.7%)	— / —
fj-kmeans	25	✅ 2850 ms (66 iters)	✅ 2848 ms (66 iters)	≈ -0.1% (±2.5%)	— / —
future-genetic	21	✅ 2061 ms (90 iters)	✅ 2142 ms (86 iters)	🔴 +3.9%	— / —
future-genetic	25	✅ 2019 ms (92 iters)	✅ 2043 ms (91 iters)	≈ +1.2% (±2.6%)	— / —
naive-bayes	21	✅ 1306 ms (132 iters)	✅ 1267 ms (135 iters)	≈ -3% (±32.1%)	— / —
naive-bayes	25	✅ 1004 ms (170 iters)	✅ 1012 ms (169 iters)	≈ +0.8% (±31.7%)	— / —
reactors	21	✅ 15889 ms (15 iters)	✅ 15952 ms (15 iters)	≈ +0.4% (±7.3%)	— / —
reactors	25	✅ 18632 ms (15 iters)	✅ 18335 ms (15 iters)	≈ -1.6% (±4.6%)	— / —

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	✅ / ✅	✅ / ✅	1 / 2	1922 / 1896	✅ / ✅	✅ / ✅
akka-uct	25	✅ / ✅	✅ / ✅	✅ / 3	2247 / 2407	✅ / ✅	✅ / ✅
finagle-chirper	21	✅ / ✅	✅ / ✅	3 / 3	8773 / 8354	✅ / ✅	✅ / ✅
finagle-chirper	25	✅ / ✅	✅ / ✅	1 / 1	8322 / 8456	✅ / ✅	✅ / ✅
fj-kmeans	21	✅ / ✅	✅ / ✅	5 / 1	1222 / 1289	✅ / ✅	✅ / ✅
fj-kmeans	25	✅ / ✅	✅ / ✅	3 / 3	1268 / 1286	✅ / ✅	✅ / ✅
future-genetic	21	✅ / ✅	✅ / ✅	3 / ✅	2986 / 2986	✅ / ✅	✅ / ✅
future-genetic	25	✅ / ✅	✅ / ✅	2 / 1	2969 / 2912	✅ / ✅	✅ / ✅
naive-bayes	21	✅ / ✅	✅ / ✅	5 / 2	3528 / 3525	✅ / ✅	✅ / ✅
naive-bayes	25	✅ / ✅	✅ / ✅	3 / 1	3507 / 3462	✅ / ✅	✅ / ✅
reactors	21	✅ / ✅	✅ / ✅	✅ / ✅	1594 / 1600	✅ / ✅	✅ / ✅
reactors	25	✅ / ✅	✅ / ✅	2 / 3	1948 / 1838	✅ / ✅	✅ / ✅

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Benchmark Results (commit f5b81de)

Pipeline: https://gitlab.ddbuild.io/DataDog/apm-reliability/benchmarking-platform/-/pipelines/128545992 Commit: f5b81de3bea33b0718817cf344261bda92848074

⚠️ Significant outliers

⚠️ future-genetic (JDK 25): wallclock unwinds skipped — latest 0 → dev 2874 (new)

Runtime details (per benchmark × JDK)

Benchmark	JDK	Latest	Dev	Δ (dev vs latest)	Issues L/D
akka-uct	21	✅ 10374 ms (21 iters)	✅ 10199 ms (21 iters)	≈ -1.7% (±10.6%)	— / —
akka-uct	25	✅ 8859 ms (24 iters)	✅ 8855 ms (24 iters)	≈ -0% (±9.8%)	— / —
finagle-chirper	21	✅ 6011 ms (33 iters)	✅ 5983 ms (33 iters)	≈ -0.5% (±25.1%)	⚠️ W:3 / ⚠️ W:3
finagle-chirper	25	✅ 5452 ms (36 iters)	✅ 5461 ms (36 iters)	≈ +0.2% (±23.8%)	⚠️ W:3 / ⚠️ W:3
fj-kmeans	21	✅ 2770 ms (68 iters)	✅ 2700 ms (70 iters)	≈ -2.5% (±2.7%)	— / —
fj-kmeans	25	✅ 2849 ms (66 iters)	✅ 2855 ms (66 iters)	≈ +0.2% (±2.6%)	— / —
future-genetic	21	✅ 2106 ms (88 iters)	✅ 2071 ms (90 iters)	≈ -1.7% (±2.7%)	— / —
naive-bayes	21	✅ 1257 ms (136 iters)	✅ 1340 ms (128 iters)	≈ +6.6% (±33.3%)	— / —
reactors	21	✅ 16574 ms (15 iters)	✅ 16423 ms (15 iters)	≈ -0.9% (±7.9%)	— / —
reactors	25	✅ 18460 ms (15 iters)	✅ 18165 ms (15 iters)	≈ -1.6% (±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	✅ / ✅	✅ / ✅	✅ / 1	2335 / 2304	✅ / ✅	✅ / ✅
finagle-chirper	21	✅ / ✅	✅ / ✅	5 / 6	8621 / 8635	✅ / ✅	✅ / ✅
finagle-chirper	25	✅ / ✅	✅ / ✅	2 / 1	8286 / 8482	✅ / ✅	✅ / ✅
fj-kmeans	21	✅ / ✅	✅ / ✅	2 / 2	1285 / 1273	✅ / ✅	✅ / ✅
fj-kmeans	25	✅ / ✅	✅ / ✅	✅ / ✅	1281 / 1282	✅ / ✅	✅ / ✅
future-genetic	21	✅ / ✅	✅ / ✅	1 / 1	2946 / 3005	✅ / ✅	✅ / ✅
future-genetic	25	✅ / ✅	✅ / ✅	✅ / 2	✅ / 2874	✅ / ✅	✅ / ✅
naive-bayes	21	✅ / ✅	✅ / ✅	4 / 4	3524 / 3523	✅ / ✅	✅ / ✅
naive-bayes	25	✅ / ✅	✅ / ✅	7 / 3	3478 / 3496	✅ / ✅	✅ / ✅
reactors	21	✅ / ✅	✅ / ✅	1 / ✅	1718 / 1560	✅ / ✅	✅ / ✅
reactors	25	✅ / ✅	✅ / ✅	2 / ✅	1863 / 1781	✅ / ✅	✅ / ✅

…lock-all-threads

Scan-Build Report

User:	runner@runnervm76f27
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:	Fri Aug 21 14:18:31 2026

Bug Summary

Logic error
Bug Type	Quantity	Display?
All Bugs	1
Dereference of null pointer	1

Reports

Bug Group	Bug Type ▾	File	Function/Method	Line	Path Length
Logic error	Dereference of null pointer	profiler.h	findLibraryByAddress	522	28

Stale JMC IItemCollection usage predated the jafar migration on main and caused a compile failure once this branch was rebased onto it.

✅ All 40 integration tests passed

📊 Dashboard · 👷 Pipeline · 📦 26ae49b9

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Sphinx Review found 2 critical/high severity finding(s) that must be addressed.

🗿 🤖 🔴

[Sphinx Review — MEDIUM] onThreadEnd() now unconditionally calls _thread_filter.unregisterThread()/unregisterThreadByTid() (both mutex-guarded) for every JVMTI ThreadEnd event whenever any profiling engine is active, instead of being gated behind the thread-filter registry's active/enabled state as before.

Suggestion: Gate the else-branch (and ideally both branches) behind _thread_filter.registryActive() (or a cheaper lock-free check) so thread teardown for profiling sessions that never use the registry does not pay for a mutex acquisition.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

# Conflicts: # ddprof-lib/src/main/cpp/javaApi.cpp

Could you, please, also take a look if it makes sense to add new adversaries in the chaos tests, or some fuzzing tests?

QQ: Any reason this is done unconditionally? Eg. regardless of whether profilerStarted == true?

It was originally done this way to prevent any garbage coming from another test interferes with this test. But you're right in a sense that no test currently writes context without calling start(). I'd still keep it like that though as it is the most defensive way of doing.

This might be a premature optimization, but did you consider making the code friendlier to potential vectorization?
Probably not necessary to act upon this immediately, unless the benchmarks would show this function becoming a hotspot.

Honestly I didn't for now, but it is definitely something to consider.

kaahos force-pushed the paul.fournillon/wallclock-all-threads branch 3 times, most recently from 3902a14 to f302dd5 Compare July 19, 2026 12:00

kaahos changed the title feat(wall): add configurable wall thread scope feat(wall): support signal suppression for unfiltered threads Jul 19, 2026

kaahos force-pushed the paul.fournillon/wallclock-all-threads branch 2 times, most recently from 0ad425c to fb1c44d Compare July 19, 2026 18:43

feat(wall): track all threads for unfiltered wall-clock precheck

1118f62

kaahos force-pushed the paul.fournillon/wallclock-all-threads branch from fb1c44d to 1118f62 Compare July 19, 2026 21:16

Merge branch 'main' into paul.fournillon/wallclock-all-threads

40dbe8e

Merge branch 'main' into paul.fournillon/wallclock-all-threads

d82291f

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Comment thread ddprof-lib/src/main/cpp/wallClockCandidateSelector.h

Comment thread ddprof-lib/src/test/cpp/wallClockCandidateSelector_ut.cpp

Comment thread ddprof-test/src/test/java/com/datadoghq/profiler/wallclock/UnfilteredWallPrecheckTest.java

fix: apply review suggestions

ec76f58

Merge branch 'main' into paul.fournillon/wallclock-all-threads

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test: remove obsolete thread context reset

f5b81de

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Merge remote-tracking branch 'origin/main' into paul.fournillon/wallc…

b397ac9

…lock-all-threads

fix(test): migrate UnfilteredWallPrecheckTest to jafar JFR API

599c21e

Stale JMC IItemCollection usage predated the jafar migration on main and caused a compile failure once this branch was rebased onto it.

Merge branch 'main' into paul.fournillon/wallclock-all-threads

a68d3f2

kaahos marked this pull request as ready for review August 17, 2026 14:03

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

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jbachorik added the sphinx:critical Sphinx: critical — human review required label Aug 18, 2026

kaahos force-pushed the paul.fournillon/wallclock-all-threads branch from af36f26 to 2a142a6 Compare August 18, 2026 18:41

fix: address some review comments

391fdd2

kaahos force-pushed the paul.fournillon/wallclock-all-threads branch from 2a142a6 to 391fdd2 Compare August 18, 2026 18:58

kaahos requested a review from jbachorik August 18, 2026 19:03

kaahos and others added 5 commits August 19, 2026 10:05

fix: address review comments

d6f5b1a

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

fix: avoid CAS on context-window enter/exit hot path

4d2c505

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Merge branch 'main' into paul.fournillon/wallclock-all-threads

8ef675e

# Conflicts: # ddprof-lib/src/main/cpp/javaApi.cpp

fix: fix musl bug

172e453

Merge branch 'main' into paul.fournillon/wallclock-all-threads

1b94815

kaahos force-pushed the paul.fournillon/wallclock-all-threads branch from 5c765fa to 1b94815 Compare August 20, 2026 13:01

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kaahos requested a review from jbachorik August 21, 2026 14:03

fix: address some review comments

26ae49b

kaahos force-pushed the paul.fournillon/wallclock-all-threads branch from e0ec41e to 26ae49b Compare August 21, 2026 14:16

+                                          jint num_frames) {
+                // The source and destination commonly refer to the two views of the same
+                // CallTraceBuffer union. Read both source fields before either write.
+                for (jint i = 0; i < num_frames; ++i) {

-                  if (_thread_filter.enabled()) {
-                    _thread_filter.unregisterThread(slot_id);
+                  if (slot_id >= 0) {

                           profiler.stop();
                           profilerStarted = false;
                       }
+                      profiler.clearTraceContext();

feat(wall): support signal suppression for unfiltered threads by kaahos · Pull Request #663 · DataDog/java-profiler · GitHub

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feat(wall): support signal suppression for unfiltered threads - #663

feat(wall): support signal suppression for unfiltered threads#663kaahos wants to merge 27 commits intomainDataDog/java-profiler:mainfrom paul.fournillon/wallclock-all-threadsDataDog/java-profiler:paul.fournillon/wallclock-all-threadsCopy head branch name to clipboard

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Benchmark Results (commit fb1c44d)

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Benchmark Results (commit 1118f62)

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Benchmark Results (commit d82291f)

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Benchmark Results (commit ec76f58)

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Benchmark Results (commit 82e05b6)

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feat(wall): support signal suppression for unfiltered threads#663
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