Skip synchronized(unsafeTags) on owner-thread tag writes by bm1549 · Pull Request #11082 · DataDog/dd-trace-java

bm1549 · 2026-04-10T18:31:23Z

What Does This Do

Optimizes DDSpanContext tag writes by skipping synchronized(unsafeTags) when the writing thread is the span's creating thread (the common case). A volatile tagWriteState field tracks whether the span is in owner-only mode or shared mode. Once any non-owner thread accesses tags or the span finishes, it transitions to shared mode permanently and all subsequent accesses take the lock.

Motivation

Every setTag() / setMetric() call acquires synchronized(unsafeTags) — ~27 lock sites total. Spans are almost always written by a single thread, so the lock is uncontended overhead (~20-30ns per acquire/release × 5-20 tags per span × millions of spans/second). This optimization eliminates that overhead on the fast path by replacing the lock with a volatile read + thread ID comparison.

Safety model:

volatile int tagWriteState tracks STATE_OWNER (0) vs STATE_SHARED (1). Once shared, never reverts.
Owner thread: volatile read + threadId check → skip lock
Non-owner thread: take lock + sticky-transition to STATE_SHARED
finish() calls transitionToShared() so post-finish writes (decorators/handlers) always take the lock
Long-running spans disable the optimization at construction since the writer thread may read tags on unfinished spans

Benchmark Results

JMH benchmarks, 2 forks × 5 warmup + 5 measurement iterations, back-to-back on same machine. Owner-thread benchmarks use @Threads(1), cross-thread uses @Threads(8).

JDK 21 (Zulu 21.0.1) — biased locking removed

Benchmark	Baseline	Optimized	Unit	Change
`fullLifecycle_tenTags`	2.288 ± 0.111	2.559 ± 0.091	ops/µs	+11.8%
`setStringTag_ownerThread`	0.032 ± 0.002	0.037 ± 0.004	ops/ns	+15.6%
`setIntTag_ownerThread`	0.030 ± 0.004	0.038 ± 0.017	ops/ns	+26.7%
`setTenTags_ownerThread`	0.006 ± 0.001	0.008 ± 0.001	ops/ns	+33.3%
`setStringTag_crossThread` (8T)	0.019 ± 0.003	0.017 ± 0.002	ops/ns	~neutral (within error)

JDK 8 (Zulu 8u372) — biased locking enabled

Benchmark	Baseline	Optimized	Unit	Change
`fullLifecycle_tenTags`	2.043 ± 0.071	2.132 ± 0.126	ops/µs	+4.4%
`setStringTag_ownerThread`	0.026 ± 0.002	0.029 ± 0.002	ops/ns	+11.5%
`setIntTag_ownerThread`	0.040 ± 0.016	0.035 ± 0.009	ops/ns	~neutral (within error)
`setTenTags_ownerThread`	0.007 ± 0.001	0.007 ± 0.001	ops/ns	~neutral
`setStringTag_crossThread` (8T)	0.022 ± 0.004	0.022 ± 0.005	ops/ns	~neutral (no regression)

Analysis

On JDK 21 (where biased locking was removed in JDK 15), uncontended synchronized is more expensive and the optimization shows clear gains: +12-33% across all owner-thread benchmarks. The full lifecycle benchmark (create + 10 tags + finish) shows +11.8% throughput improvement.

On JDK 8 (biased locking enabled), the JVM already optimizes uncontended locks, so gains are modest (+4-12%).

Cross-thread path: no regression on either JDK. The slow path (non-owner threads) takes the lock just like before, with one additional volatile read of tagWriteState.

Additional Notes

synchronized(unsafeTags) is kept on reader paths: processTagsAndBaggage, earlyProcessTags, getTags, toString
The TOCTOU race window for cross-thread writes is accepted — same best-effort as today, the existing codebase comments say "tags will rarely, if ever, be read and modified concurrently"
Added DDSpanContextConcurrencyTest (9 JUnit 5 tests including 3 targeted cross-thread stress tests) and SpanTagBenchmark (5 JMH benchmarks)

Contributor Checklist

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tag: ai generated

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Spans are almost always written by a single thread, so the lock on every setTag/setMetric call is uncontended overhead. This adds a volatile tagWriteState check: if the current thread is the span's creating thread (STATE_OWNER), tag writes skip the lock entirely. Non-owner threads and post-finish writes take the lock and sticky-transition to STATE_SHARED. Long-running spans disable the optimization at construction since the writer thread may read tags on unfinished spans. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pr-commenter · 2026-04-10T19:21:56Z

Benchmarks

Startup

Parameters

	Baseline	Candidate
baseline_or_candidate	baseline	candidate
git_branch	master	brian.marks/thread-owned-tags
git_commit_date	1775834061	1775857722
git_commit_sha	`5ab378f`	`d664ab2`
release_version	1.62.0-SNAPSHOT~5ab378f780	1.62.0-SNAPSHOT~d664ab2db5

See matching parameters

	Baseline	Candidate
application	insecure-bank	insecure-bank
ci_job_date	1775859540	1775859540
ci_job_id	1587287876	1587287876
ci_pipeline_id	107208604	107208604
cpu_model	Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz	Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz
kernel_version	Linux runner-zfyrx7zua-project-304-concurrent-0-ii911gvi 6.8.0-1031-aws #33~22.04.1-Ubuntu SMP Thu Jun 26 14:22:30 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux	Linux runner-zfyrx7zua-project-304-concurrent-0-ii911gvi 6.8.0-1031-aws #33~22.04.1-Ubuntu SMP Thu Jun 26 14:22:30 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
module	Agent	Agent
parent	None	None

Summary

Found 0 performance improvements and 0 performance regressions! Performance is the same for 58 metrics, 13 unstable metrics.

Startup time reports for insecure-bank

gantt
    title insecure-bank - global startup overhead: candidate=1.62.0-SNAPSHOT~d664ab2db5, baseline=1.62.0-SNAPSHOT~5ab378f780

    dateFormat X
    axisFormat %s
section tracing
Agent [baseline] (1.06 s) : 0, 1059848
Total [baseline] (8.839 s) : 0, 8839209
Agent [candidate] (1.074 s) : 0, 1073851
Total [candidate] (8.886 s) : 0, 8885932
section iast
Agent [baseline] (1.223 s) : 0, 1223212
Total [baseline] (9.586 s) : 0, 9585743
Agent [candidate] (1.233 s) : 0, 1232543
Total [candidate] (9.575 s) : 0, 9574588

baseline results

Module	Variant	Duration	Δ tracing
Agent	tracing	1.06 s	-
Agent	iast	1.223 s	163.364 ms (15.4%)
Total	tracing	8.839 s	-
Total	iast	9.586 s	746.534 ms (8.4%)

candidate results

Module	Variant	Duration	Δ tracing
Agent	tracing	1.074 s	-
Agent	iast	1.233 s	158.692 ms (14.8%)
Total	tracing	8.886 s	-
Total	iast	9.575 s	688.656 ms (7.7%)

gantt
    title insecure-bank - break down per module: candidate=1.62.0-SNAPSHOT~d664ab2db5, baseline=1.62.0-SNAPSHOT~5ab378f780

    dateFormat X
    axisFormat %s
section tracing
crashtracking [baseline] (1.256 ms) : 0, 1256
crashtracking [candidate] (1.243 ms) : 0, 1243
BytebuddyAgent [baseline] (636.08 ms) : 0, 636080
BytebuddyAgent [candidate] (642.295 ms) : 0, 642295
AgentMeter [baseline] (29.748 ms) : 0, 29748
AgentMeter [candidate] (29.797 ms) : 0, 29797
GlobalTracer [baseline] (249.211 ms) : 0, 249211
GlobalTracer [candidate] (253.92 ms) : 0, 253920
AppSec [baseline] (31.95 ms) : 0, 31950
AppSec [candidate] (32.769 ms) : 0, 32769
Debugger [baseline] (59.284 ms) : 0, 59284
Debugger [candidate] (60.663 ms) : 0, 60663
Remote Config [baseline] (596.164 µs) : 0, 596
Remote Config [candidate] (623.001 µs) : 0, 623
Telemetry [baseline] (8.08 ms) : 0, 8080
Telemetry [candidate] (8.321 ms) : 0, 8321
Flare Poller [baseline] (7.392 ms) : 0, 7392
Flare Poller [candidate] (7.446 ms) : 0, 7446
section iast
crashtracking [baseline] (1.238 ms) : 0, 1238
crashtracking [candidate] (1.252 ms) : 0, 1252
BytebuddyAgent [baseline] (800.362 ms) : 0, 800362
BytebuddyAgent [candidate] (806.847 ms) : 0, 806847
AgentMeter [baseline] (11.344 ms) : 0, 11344
AgentMeter [candidate] (11.435 ms) : 0, 11435
GlobalTracer [baseline] (239.127 ms) : 0, 239127
GlobalTracer [candidate] (241.228 ms) : 0, 241228
AppSec [baseline] (31.811 ms) : 0, 31811
AppSec [candidate] (30.336 ms) : 0, 30336
Debugger [baseline] (58.642 ms) : 0, 58642
Debugger [candidate] (61.841 ms) : 0, 61841
Remote Config [baseline] (1.15 ms) : 0, 1150
Remote Config [candidate] (533.293 µs) : 0, 533
Telemetry [baseline] (13.635 ms) : 0, 13635
Telemetry [candidate] (12.972 ms) : 0, 12972
Flare Poller [baseline] (3.502 ms) : 0, 3502
Flare Poller [candidate] (3.485 ms) : 0, 3485
IAST [baseline] (25.892 ms) : 0, 25892
IAST [candidate] (25.875 ms) : 0, 25875

Startup time reports for petclinic

gantt
    title petclinic - global startup overhead: candidate=1.62.0-SNAPSHOT~d664ab2db5, baseline=1.62.0-SNAPSHOT~5ab378f780

    dateFormat X
    axisFormat %s
section tracing
Agent [baseline] (1.06 s) : 0, 1059893
Total [baseline] (11.074 s) : 0, 11073783
Agent [candidate] (1.063 s) : 0, 1063158
Total [candidate] (11.144 s) : 0, 11143810
section appsec
Agent [baseline] (1.251 s) : 0, 1250721
Total [baseline] (11.118 s) : 0, 11118258
Agent [candidate] (1.257 s) : 0, 1256515
Total [candidate] (11.117 s) : 0, 11116930
section iast
Agent [baseline] (1.225 s) : 0, 1225099
Total [baseline] (10.552 s) : 0, 10552399
Agent [candidate] (1.246 s) : 0, 1246267
Total [candidate] (11.331 s) : 0, 11330949
section profiling
Agent [baseline] (1.188 s) : 0, 1187723
Total [baseline] (11.222 s) : 0, 11222371
Agent [candidate] (1.206 s) : 0, 1205913
Total [candidate] (11.209 s) : 0, 11209296

baseline results

Module	Variant	Duration	Δ tracing
Agent	tracing	1.06 s	-
Agent	appsec	1.251 s	190.828 ms (18.0%)
Agent	iast	1.225 s	165.205 ms (15.6%)
Agent	profiling	1.188 s	127.829 ms (12.1%)
Total	tracing	11.074 s	-
Total	appsec	11.118 s	44.475 ms (0.4%)
Total	iast	10.552 s	-521.384 ms (-4.7%)
Total	profiling	11.222 s	148.588 ms (1.3%)

candidate results

Module	Variant	Duration	Δ tracing
Agent	tracing	1.063 s	-
Agent	appsec	1.257 s	193.357 ms (18.2%)
Agent	iast	1.246 s	183.109 ms (17.2%)
Agent	profiling	1.206 s	142.756 ms (13.4%)
Total	tracing	11.144 s	-
Total	appsec	11.117 s	-26.881 ms (-0.2%)
Total	iast	11.331 s	187.139 ms (1.7%)
Total	profiling	11.209 s	65.486 ms (0.6%)

gantt
    title petclinic - break down per module: candidate=1.62.0-SNAPSHOT~d664ab2db5, baseline=1.62.0-SNAPSHOT~5ab378f780

    dateFormat X
    axisFormat %s
section tracing
crashtracking [baseline] (1.234 ms) : 0, 1234
crashtracking [candidate] (1.245 ms) : 0, 1245
BytebuddyAgent [baseline] (634.079 ms) : 0, 634079
BytebuddyAgent [candidate] (635.92 ms) : 0, 635920
AgentMeter [baseline] (29.532 ms) : 0, 29532
AgentMeter [candidate] (29.54 ms) : 0, 29540
GlobalTracer [baseline] (249.946 ms) : 0, 249946
GlobalTracer [candidate] (250.928 ms) : 0, 250928
AppSec [baseline] (32.104 ms) : 0, 32104
AppSec [candidate] (32.12 ms) : 0, 32120
Debugger [baseline] (60.432 ms) : 0, 60432
Debugger [candidate] (60.621 ms) : 0, 60621
Remote Config [baseline] (601.648 µs) : 0, 602
Remote Config [candidate] (608.878 µs) : 0, 609
Telemetry [baseline] (8.15 ms) : 0, 8150
Telemetry [candidate] (8.162 ms) : 0, 8162
Flare Poller [baseline] (7.516 ms) : 0, 7516
Flare Poller [candidate] (7.533 ms) : 0, 7533
section appsec
crashtracking [baseline] (1.224 ms) : 0, 1224
crashtracking [candidate] (1.255 ms) : 0, 1255
BytebuddyAgent [baseline] (663.323 ms) : 0, 663323
BytebuddyAgent [candidate] (665.984 ms) : 0, 665984
AgentMeter [baseline] (12.105 ms) : 0, 12105
AgentMeter [candidate] (12.107 ms) : 0, 12107
GlobalTracer [baseline] (249.837 ms) : 0, 249837
GlobalTracer [candidate] (250.849 ms) : 0, 250849
IAST [baseline] (24.526 ms) : 0, 24526
IAST [candidate] (24.792 ms) : 0, 24792
AppSec [baseline] (184.685 ms) : 0, 184685
AppSec [candidate] (185.503 ms) : 0, 185503
Debugger [baseline] (65.841 ms) : 0, 65841
Debugger [candidate] (66.382 ms) : 0, 66382
Remote Config [baseline] (616.178 µs) : 0, 616
Remote Config [candidate] (605.866 µs) : 0, 606
Telemetry [baseline] (8.593 ms) : 0, 8593
Telemetry [candidate] (8.665 ms) : 0, 8665
Flare Poller [baseline] (3.571 ms) : 0, 3571
Flare Poller [candidate] (3.594 ms) : 0, 3594
section iast
crashtracking [baseline] (1.226 ms) : 0, 1226
crashtracking [candidate] (1.256 ms) : 0, 1256
BytebuddyAgent [baseline] (800.481 ms) : 0, 800481
BytebuddyAgent [candidate] (816.191 ms) : 0, 816191
AgentMeter [baseline] (11.399 ms) : 0, 11399
AgentMeter [candidate] (11.663 ms) : 0, 11663
GlobalTracer [baseline] (239.483 ms) : 0, 239483
GlobalTracer [candidate] (243.538 ms) : 0, 243538
IAST [baseline] (25.857 ms) : 0, 25857
IAST [candidate] (26.162 ms) : 0, 26162
AppSec [baseline] (29.043 ms) : 0, 29043
AppSec [candidate] (32.101 ms) : 0, 32101
Debugger [baseline] (63.822 ms) : 0, 63822
Debugger [candidate] (61.43 ms) : 0, 61430
Remote Config [baseline] (1.197 ms) : 0, 1197
Remote Config [candidate] (533.065 µs) : 0, 533
Telemetry [baseline] (12.679 ms) : 0, 12679
Telemetry [candidate] (13.116 ms) : 0, 13116
Flare Poller [baseline] (3.584 ms) : 0, 3584
Flare Poller [candidate] (3.484 ms) : 0, 3484
section profiling
crashtracking [baseline] (1.196 ms) : 0, 1196
crashtracking [candidate] (1.232 ms) : 0, 1232
BytebuddyAgent [baseline] (692.325 ms) : 0, 692325
BytebuddyAgent [candidate] (704.741 ms) : 0, 704741
AgentMeter [baseline] (9.128 ms) : 0, 9128
AgentMeter [candidate] (9.302 ms) : 0, 9302
GlobalTracer [baseline] (207.897 ms) : 0, 207897
GlobalTracer [candidate] (210.259 ms) : 0, 210259
AppSec [baseline] (32.605 ms) : 0, 32605
AppSec [candidate] (33.124 ms) : 0, 33124
Debugger [baseline] (66.028 ms) : 0, 66028
Debugger [candidate] (66.832 ms) : 0, 66832
Remote Config [baseline] (570.605 µs) : 0, 571
Remote Config [candidate] (588.57 µs) : 0, 589
Telemetry [baseline] (7.822 ms) : 0, 7822
Telemetry [candidate] (7.974 ms) : 0, 7974
Flare Poller [baseline] (3.562 ms) : 0, 3562
Flare Poller [candidate] (3.571 ms) : 0, 3571
ProfilingAgent [baseline] (95.25 ms) : 0, 95250
ProfilingAgent [candidate] (95.56 ms) : 0, 95560
Profiling [baseline] (95.828 ms) : 0, 95828
Profiling [candidate] (96.135 ms) : 0, 96135

Load

Parameters

	Baseline	Candidate
baseline_or_candidate	baseline	candidate
git_branch	master	brian.marks/thread-owned-tags
git_commit_date	1775834061	1775857722
git_commit_sha	`5ab378f`	`d664ab2`
release_version	1.62.0-SNAPSHOT~5ab378f780	1.62.0-SNAPSHOT~d664ab2db5

See matching parameters

	Baseline	Candidate
application	insecure-bank	insecure-bank
ci_job_date	1775860181	1775860181
ci_job_id	1587287877	1587287877
ci_pipeline_id	107208604	107208604
cpu_model	Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz	Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz
kernel_version	Linux runner-zfyrx7zua-project-304-concurrent-0-hp15gq3q 6.8.0-1031-aws #33~22.04.1-Ubuntu SMP Thu Jun 26 14:22:30 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux	Linux runner-zfyrx7zua-project-304-concurrent-0-hp15gq3q 6.8.0-1031-aws #33~22.04.1-Ubuntu SMP Thu Jun 26 14:22:30 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux

Summary

Found 0 performance improvements and 1 performance regressions! Performance is the same for 20 metrics, 15 unstable metrics.

scenario	Δ mean agg_http_req_duration_p50	Δ mean agg_http_req_duration_p95	Δ mean throughput	candidate mean agg_http_req_duration_p50	candidate mean agg_http_req_duration_p95	candidate mean throughput	baseline mean agg_http_req_duration_p50	baseline mean agg_http_req_duration_p95	baseline mean throughput
scenario:load:petclinic:iast:high_load	worse [+347.923µs; +706.338µs] or [+2.018%; +4.098%]	same [-65.515µs; +1131.133µs] or [-0.229%; +3.960%]	unstable [-33.380op/s; +23.068op/s] or [-12.677%; +8.761%]	17.765ms	29.099ms	258.156op/s	17.238ms	28.566ms	263.312op/s

Request duration reports for petclinic

gantt
    title petclinic - request duration [CI 0.99] : candidate=1.62.0-SNAPSHOT~d664ab2db5, baseline=1.62.0-SNAPSHOT~5ab378f780
    dateFormat X
    axisFormat %s
section baseline
no_agent (19.251 ms) : 19054, 19448
.   : milestone, 19251,
appsec (18.682 ms) : 18493, 18872
.   : milestone, 18682,
code_origins (18.426 ms) : 18243, 18608
.   : milestone, 18426,
iast (17.721 ms) : 17545, 17897
.   : milestone, 17721,
profiling (19.649 ms) : 19448, 19851
.   : milestone, 19649,
tracing (18.015 ms) : 17838, 18191
.   : milestone, 18015,
section candidate
no_agent (19.144 ms) : 18948, 19340
.   : milestone, 19144,
appsec (18.649 ms) : 18460, 18837
.   : milestone, 18649,
code_origins (18.188 ms) : 18009, 18368
.   : milestone, 18188,
iast (18.079 ms) : 17897, 18261
.   : milestone, 18079,
profiling (19.298 ms) : 19105, 19490
.   : milestone, 19298,
tracing (18.076 ms) : 17896, 18256
.   : milestone, 18076,

baseline results

Variant	Request duration [CI 0.99]	Δ no_agent
no_agent	19.251 ms [19.054 ms, 19.448 ms]	-
appsec	18.682 ms [18.493 ms, 18.872 ms]	-568.459 µs (-3.0%)
code_origins	18.426 ms [18.243 ms, 18.608 ms]	-825.136 µs (-4.3%)
iast	17.721 ms [17.545 ms, 17.897 ms]	-1.529 ms (-7.9%)
profiling	19.649 ms [19.448 ms, 19.851 ms]	398.282 µs (2.1%)
tracing	18.015 ms [17.838 ms, 18.191 ms]	-1.236 ms (-6.4%)

candidate results

Variant	Request duration [CI 0.99]	Δ no_agent
no_agent	19.144 ms [18.948 ms, 19.34 ms]	-
appsec	18.649 ms [18.46 ms, 18.837 ms]	-495.591 µs (-2.6%)
code_origins	18.188 ms [18.009 ms, 18.368 ms]	-956.01 µs (-5.0%)
iast	18.079 ms [17.897 ms, 18.261 ms]	-1.065 ms (-5.6%)
profiling	19.298 ms [19.105 ms, 19.49 ms]	153.274 µs (0.8%)
tracing	18.076 ms [17.896 ms, 18.256 ms]	-1.068 ms (-5.6%)

Request duration reports for insecure-bank

gantt
    title insecure-bank - request duration [CI 0.99] : candidate=1.62.0-SNAPSHOT~d664ab2db5, baseline=1.62.0-SNAPSHOT~5ab378f780
    dateFormat X
    axisFormat %s
section baseline
no_agent (1.243 ms) : 1231, 1255
.   : milestone, 1243,
iast (3.289 ms) : 3247, 3332
.   : milestone, 3289,
iast_FULL (6.228 ms) : 6164, 6293
.   : milestone, 6228,
iast_GLOBAL (3.574 ms) : 3520, 3627
.   : milestone, 3574,
profiling (2.459 ms) : 2434, 2483
.   : milestone, 2459,
tracing (1.934 ms) : 1918, 1950
.   : milestone, 1934,
section candidate
no_agent (1.228 ms) : 1216, 1240
.   : milestone, 1228,
iast (3.208 ms) : 3167, 3249
.   : milestone, 3208,
iast_FULL (5.991 ms) : 5930, 6051
.   : milestone, 5991,
iast_GLOBAL (3.611 ms) : 3552, 3670
.   : milestone, 3611,
profiling (2.379 ms) : 2354, 2405
.   : milestone, 2379,
tracing (1.878 ms) : 1862, 1894
.   : milestone, 1878,

baseline results

Variant	Request duration [CI 0.99]	Δ no_agent
no_agent	1.243 ms [1.231 ms, 1.255 ms]	-
iast	3.289 ms [3.247 ms, 3.332 ms]	2.046 ms (164.6%)
iast_FULL	6.228 ms [6.164 ms, 6.293 ms]	4.985 ms (401.0%)
iast_GLOBAL	3.574 ms [3.52 ms, 3.627 ms]	2.33 ms (187.5%)
profiling	2.459 ms [2.434 ms, 2.483 ms]	1.216 ms (97.8%)
tracing	1.934 ms [1.918 ms, 1.95 ms]	690.794 µs (55.6%)

candidate results

Variant	Request duration [CI 0.99]	Δ no_agent
no_agent	1.228 ms [1.216 ms, 1.24 ms]	-
iast	3.208 ms [3.167 ms, 3.249 ms]	1.98 ms (161.3%)
iast_FULL	5.991 ms [5.93 ms, 6.051 ms]	4.763 ms (387.9%)
iast_GLOBAL	3.611 ms [3.552 ms, 3.67 ms]	2.383 ms (194.1%)
profiling	2.379 ms [2.354 ms, 2.405 ms]	1.151 ms (93.8%)
tracing	1.878 ms [1.862 ms, 1.894 ms]	650.558 µs (53.0%)

Dacapo

Parameters

	Baseline	Candidate
baseline_or_candidate	baseline	candidate
git_branch	master	brian.marks/thread-owned-tags
git_commit_date	1775834061	1775857722
git_commit_sha	`5ab378f`	`d664ab2`
release_version	1.62.0-SNAPSHOT~5ab378f780	1.62.0-SNAPSHOT~d664ab2db5

See matching parameters

	Baseline	Candidate
application	biojava	biojava
ci_job_date	1775859911	1775859911
ci_job_id	1587287878	1587287878
ci_pipeline_id	107208604	107208604
cpu_model	Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz	Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz
kernel_version	Linux runner-zfyrx7zua-project-304-concurrent-1-7decuatt 6.8.0-1031-aws #33~22.04.1-Ubuntu SMP Thu Jun 26 14:22:30 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux	Linux runner-zfyrx7zua-project-304-concurrent-1-7decuatt 6.8.0-1031-aws #33~22.04.1-Ubuntu SMP Thu Jun 26 14:22:30 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux

Summary

Found 0 performance improvements and 0 performance regressions! Performance is the same for 11 metrics, 1 unstable metrics.

Execution time for biojava

gantt
    title biojava - execution time [CI 0.99] : candidate=1.62.0-SNAPSHOT~d664ab2db5, baseline=1.62.0-SNAPSHOT~5ab378f780
    dateFormat X
    axisFormat %s
section baseline
no_agent (15.317 s) : 15317000, 15317000
.   : milestone, 15317000,
appsec (14.968 s) : 14968000, 14968000
.   : milestone, 14968000,
iast (17.984 s) : 17984000, 17984000
.   : milestone, 17984000,
iast_GLOBAL (18.113 s) : 18113000, 18113000
.   : milestone, 18113000,
profiling (15.227 s) : 15227000, 15227000
.   : milestone, 15227000,
tracing (15.062 s) : 15062000, 15062000
.   : milestone, 15062000,
section candidate
no_agent (15.514 s) : 15514000, 15514000
.   : milestone, 15514000,
appsec (14.874 s) : 14874000, 14874000
.   : milestone, 14874000,
iast (18.093 s) : 18093000, 18093000
.   : milestone, 18093000,
iast_GLOBAL (17.97 s) : 17970000, 17970000
.   : milestone, 17970000,
profiling (14.798 s) : 14798000, 14798000
.   : milestone, 14798000,
tracing (14.987 s) : 14987000, 14987000
.   : milestone, 14987000,

baseline results

Variant	Execution Time [CI 0.99]	Δ no_agent
no_agent	15.317 s [15.317 s, 15.317 s]	-
appsec	14.968 s [14.968 s, 14.968 s]	-349.0 ms (-2.3%)
iast	17.984 s [17.984 s, 17.984 s]	2.667 s (17.4%)
iast_GLOBAL	18.113 s [18.113 s, 18.113 s]	2.796 s (18.3%)
profiling	15.227 s [15.227 s, 15.227 s]	-90.0 ms (-0.6%)
tracing	15.062 s [15.062 s, 15.062 s]	-255.0 ms (-1.7%)

candidate results

Variant	Execution Time [CI 0.99]	Δ no_agent
no_agent	15.514 s [15.514 s, 15.514 s]	-
appsec	14.874 s [14.874 s, 14.874 s]	-640.0 ms (-4.1%)
iast	18.093 s [18.093 s, 18.093 s]	2.579 s (16.6%)
iast_GLOBAL	17.97 s [17.97 s, 17.97 s]	2.456 s (15.8%)
profiling	14.798 s [14.798 s, 14.798 s]	-716.0 ms (-4.6%)
tracing	14.987 s [14.987 s, 14.987 s]	-527.0 ms (-3.4%)

Execution time for tomcat

gantt
    title tomcat - execution time [CI 0.99] : candidate=1.62.0-SNAPSHOT~d664ab2db5, baseline=1.62.0-SNAPSHOT~5ab378f780
    dateFormat X
    axisFormat %s
section baseline
no_agent (1.489 ms) : 1477, 1500
.   : milestone, 1489,
appsec (3.71 ms) : 3498, 3923
.   : milestone, 3710,
iast (2.283 ms) : 2214, 2352
.   : milestone, 2283,
iast_GLOBAL (2.328 ms) : 2258, 2398
.   : milestone, 2328,
profiling (2.103 ms) : 2048, 2158
.   : milestone, 2103,
tracing (2.096 ms) : 2042, 2150
.   : milestone, 2096,
section candidate
no_agent (1.49 ms) : 1479, 1502
.   : milestone, 1490,
appsec (3.85 ms) : 3628, 4072
.   : milestone, 3850,
iast (2.278 ms) : 2209, 2348
.   : milestone, 2278,
iast_GLOBAL (2.332 ms) : 2262, 2402
.   : milestone, 2332,
profiling (2.099 ms) : 2044, 2154
.   : milestone, 2099,
tracing (2.081 ms) : 2027, 2135
.   : milestone, 2081,

baseline results

Variant	Execution Time [CI 0.99]	Δ no_agent
no_agent	1.489 ms [1.477 ms, 1.5 ms]	-
appsec	3.71 ms [3.498 ms, 3.923 ms]	2.222 ms (149.2%)
iast	2.283 ms [2.214 ms, 2.352 ms]	794.186 µs (53.4%)
iast_GLOBAL	2.328 ms [2.258 ms, 2.398 ms]	839.36 µs (56.4%)
profiling	2.103 ms [2.048 ms, 2.158 ms]	614.33 µs (41.3%)
tracing	2.096 ms [2.042 ms, 2.15 ms]	607.327 µs (40.8%)

candidate results

Variant	Execution Time [CI 0.99]	Δ no_agent
no_agent	1.49 ms [1.479 ms, 1.502 ms]	-
appsec	3.85 ms [3.628 ms, 4.072 ms]	2.36 ms (158.4%)
iast	2.278 ms [2.209 ms, 2.348 ms]	788.051 µs (52.9%)
iast_GLOBAL	2.332 ms [2.262 ms, 2.402 ms]	842.052 µs (56.5%)
profiling	2.099 ms [2.044 ms, 2.154 ms]	608.738 µs (40.8%)
tracing	2.081 ms [2.027 ms, 2.135 ms]	590.491 µs (39.6%)

@setup

Add three targeted concurrency tests that exercise the exact cross-thread tag write pattern the JMH crossThread benchmark was measuring: - crossThreadSustainedNoCrash: 8 threads × 10k setTag on same span - ownerToSharedTransition: owner writes first, then 8 threads join - manySpansCrossThread: 10k short-lived spans tagged from 8 threads All pass, proving the production code handles cross-thread writes without NPE or structural corruption. Fix the crossThread benchmark: change SharedSpan @setup from Level.Invocation to Level.Iteration. With Level.Invocation, 8 threads raced to call setup() concurrently, causing NPE when state.span was transiently null between invocations — a benchmark harness bug, not a production code bug. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

bm1549 added type: enhancement Enhancements and improvements comp: core Tracer core tag: ai generated Largely based on code generated by an AI or LLM labels Apr 10, 2026

bm1549 changed the title ~~Skip synchronized(unsafeTags) on owner-thread tag writes~~ WIP - DO NOT REVIEW: Skip synchronized(unsafeTags) on owner-thread tag writes Apr 10, 2026

bm1549 marked this pull request as ready for review April 10, 2026 19:05

bm1549 requested a review from a team as a code owner April 10, 2026 19:05

bm1549 requested a review from mhlidd April 10, 2026 19:05

bm1549 marked this pull request as draft April 10, 2026 19:23

bm1549 changed the title ~~WIP - DO NOT REVIEW: Skip synchronized(unsafeTags) on owner-thread tag writes~~ Skip synchronized(unsafeTags) on owner-thread tag writes Apr 10, 2026

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Skip synchronized(unsafeTags) on owner-thread tag writes#11082

Skip synchronized(unsafeTags) on owner-thread tag writes#11082
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JDK 21 (Zulu 21.0.1) — biased locking removed

JDK 8 (Zulu 8u372) — biased locking enabled

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