feat: OTel context sharing by morrisonlevi · Pull Request #3970 · DataDog/dd-trace-php

morrisonlevi · 2026-06-10T00:59:43Z

Description

This adds OTel context sharing using libdatadog. It adds it to both tracing (producer) and profiling (consumer).

This is mostly AI-written with a little human review as I went. It is not ready for merge, but it did pass some local end-to-end experimentation.

Reviewer checklist

Test coverage seems ok.
Appropriate labels assigned.

datadog-datadog-prod-us1 · 2026-06-10T01:01:33Z

Tests

✨ Fix all issues with BitsAI

⚠️ Warnings

🚦 75 Pipeline jobs failed

DataDog/apm-reliability/dd-trace-php | ASAN test_c: [8.3, arm64]
🧪 3 Tests failed
tmp/build_extension/tests/ext/remote_config/dynamic_config_update.phpt (Test dynamic config update) from php.tmp.build_extension.tests.ext.remote_config
001- string(3) &#34;0.5&#34;
001&#43; string(2) &#34;-1&#34;
     string(9) &#34;foo,other&#34;
     string(1) &#34;1&#34;
     string(15) &#34;foo:bar,baz:qux&#34;
--
❄️ Known flaky: tmp/build_extension/tests/ext/shm_data_internal_fns.phpt (get_loaded_remote_configs, get_agent_info, get_agent_sampling_config return correct content) from php.tmp.build_extension.tests.ext
--
     bool(true)
     bool(true)
     float(1)
008- string(17) &#34;APM_TRACING found&#34;
008&#43; string(21) &#34;APM_TRACING NOT found&#34;
     string(11) &#34;probe found&#34;
010- string(11) &#34;apm_tracing&#34;
     string(5) &#34;probe&#34;
     bool(true)
Not introduced in this PR.
View all 3 test failures
DataDog/apm-reliability/dd-trace-php | ASAN test_c: [7.4, arm64]
🧪 3 Tests failed

All test failures are known flaky.
❄️ Known flaky: tmp/build_extension/tests/ext/shm_data_internal_fns.phpt (get_loaded_remote_configs, get_agent_info, get_agent_sampling_config return correct content) from PHP.tmp.build_extension.tests.ext
008&#43; string(21) &#34;APM_TRACING NOT found&#34;
008- string(17) &#34;APM_TRACING found&#34;
010- string(11) &#34;apm_tracing&#34;
Not introduced in this PR.
❄️ Known flaky: tmp/build_extension/tests/ext/remote_config/dynamic_config_multiconfig.phpt (Test dynamic config multiconfig priority merging) from PHP.tmp.build_extension.tests.ext.remote_config
002&#43; string(2) &#34;-1&#34;
002- string(3) &#34;0.7&#34;
005&#43; string(2) &#34;-1&#34;
005- string(3) &#34;0.3&#34;
Not introduced in this PR.
View all 3 test failures
DataDog/apm-reliability/dd-trace-php | ASAN test_c with multiple observers: [8.1]
View all 75 failed jobs.

ℹ️ Info

No other issues found (see more)

❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 54.08% (-0.03%)

Useful? React with 👍 / 👎

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

🔗 Commit SHA: 0037ab7 | Docs | Datadog PR Page | Give us feedback!}

pr-commenter · 2026-06-10T01:13:45Z

Benchmarks [ profiler ]

Benchmark execution time: 2026-06-23 10:12:36

Comparing candidate commit 0037ab7 in PR branch levi/otel-thread-context with baseline commit 1d6b7ca in branch master.

Found 0 performance improvements and 3 performance regressions! Performance is the same for 27 metrics, 6 unstable metrics.

Explanation

This is an A/B test comparing a candidate commit's performance against that of a baseline commit. Performance changes are noted in the tables below as:

🟩 = significantly better candidate vs. baseline
🟥 = significantly worse candidate vs. baseline

We compute a confidence interval (CI) over the relative difference of means between metrics from the candidate and baseline commits, considering the baseline as the reference.

If the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD), the change is considered significant.

Feel free to reach out to #apm-benchmarking-platform on Slack if you have any questions.

More details about the CI and significant changes

You can imagine this CI as a range of values that is likely to contain the true difference of means between the candidate and baseline commits.

CIs of the difference of means are often centered around 0%, because often changes are not that big:

---------------------------------(------|---^--------)-------------------------------->
                              -0.6%    0%  0.3%     +1.2%
                                 |          |        |
         lower bound of the CI --'          |        |
sample mean (center of the CI) -------------'        |
         upper bound of the CI ----------------------'

As described above, a change is considered significant if the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD).

For instance, for an execution time metric, this confidence interval indicates a significantly worse performance:

----------------------------------------|---------|---(---------^---------)---------->
                                       0%        1%  1.3%      2.2%      3.1%
                                                  |   |         |         |
       significant impact threshold --------------'   |         |         |
                      lower bound of CI --------------'         |         |
       sample mean (center of the CI) --------------------------'         |
                      upper bound of CI ----------------------------------'

scenario:php-profiler-timeline-memory-control

🟥 cpu_user_time [+34.838ms; +45.170ms] or [+5.881%; +7.625%]
🟥 execution_time [+39.236ms; +43.156ms] or [+6.313%; +6.944%]

scenario:php-profiler-timeline-memory-with-profiler

🟥 execution_time [+33.587ms; +50.125ms] or [+3.216%; +4.799%]

pr-commenter · 2026-06-10T02:16:21Z

Benchmarks [ tracer ]

Benchmark execution time: 2026-06-15 22:05:54

Comparing candidate commit a449010 in PR branch levi/otel-thread-context with baseline commit 1d6b7ca in branch master.

Found 1 performance improvements and 3 performance regressions! Performance is the same for 190 metrics, 0 unstable metrics.

Explanation

This is an A/B test comparing a candidate commit's performance against that of a baseline commit. Performance changes are noted in the tables below as:

🟩 = significantly better candidate vs. baseline
🟥 = significantly worse candidate vs. baseline

We compute a confidence interval (CI) over the relative difference of means between metrics from the candidate and baseline commits, considering the baseline as the reference.

If the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD), the change is considered significant.

Feel free to reach out to #apm-benchmarking-platform on Slack if you have any questions.

More details about the CI and significant changes

You can imagine this CI as a range of values that is likely to contain the true difference of means between the candidate and baseline commits.

CIs of the difference of means are often centered around 0%, because often changes are not that big:

---------------------------------(------|---^--------)-------------------------------->
                              -0.6%    0%  0.3%     +1.2%
                                 |          |        |
         lower bound of the CI --'          |        |
sample mean (center of the CI) -------------'        |
         upper bound of the CI ----------------------'

As described above, a change is considered significant if the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD).

For instance, for an execution time metric, this confidence interval indicates a significantly worse performance:

----------------------------------------|---------|---(---------^---------)---------->
                                       0%        1%  1.3%      2.2%      3.1%
                                                  |   |         |         |
       significant impact threshold --------------'   |         |         |
                      lower bound of CI --------------'         |         |
       sample mean (center of the CI) --------------------------'         |
                      upper bound of CI ----------------------------------'

scenario:MessagePackSerializationBench/benchMessagePackSerialization-opcache

🟩 execution_time [-4.916µs; -2.944µs] or [-4.333%; -2.595%]

scenario:PDOBench/benchPDOOverhead

🟥 execution_time [+9.550µs; +11.833µs] or [+3.750%; +4.647%]

scenario:PDOBench/benchPDOOverheadWithDBM

🟥 execution_time [+9.456µs; +12.357µs] or [+3.703%; +4.839%]

scenario:PHPRedisBench/benchRedisOverhead

🟥 execution_time [+53.107µs; +70.110µs] or [+5.279%; +6.969%]

…ntext # Conflicts: # Cargo.lock # Makefile

…trace-php into levi/otel-thread-context

feat: otel context sharing

9d6028e

morrisonlevi added ☠️ do-not-merge/WIP profiling Relates to the Continuous Profiler tracing labels Jun 10, 2026

morrisonlevi added 2 commits June 15, 2026 11:58

Merge remote-tracking branch 'origin/master' into levi/otel-thread-co…

96f4f78

…ntext # Conflicts: # Cargo.lock # Makefile

Read OTEL thread context directly in profiler

a449010

cataphract mentioned this pull request Jun 16, 2026

refactor(otel-thread-ctx): inline thread-local resolution DataDog/libdatadog#2129

Merged

cataphract and others added 5 commits June 19, 2026 10:18

update libdatadog

bc311c3

Also publish otel context

f891d5f

demo of otel thread context reader

79ff015

Support otel thread local context

d9708a1

Merge branch 'glopes/otel-thr-ctx-metadata' of github.com:DataDog/dd-…

0037ab7

…trace-php into levi/otel-thread-context

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feat: OTel context sharing#3970

feat: OTel context sharing#3970
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levi/otel-thread-context

morrisonlevi commented Jun 10, 2026 •

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edited by datadog-prod-us1-4 Bot

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Description

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Benchmarks [ profiler ]

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scenario:php-profiler-timeline-memory-control

scenario:php-profiler-timeline-memory-with-profiler

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Benchmarks [ tracer ]

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More details about the CI and significant changes

scenario:MessagePackSerializationBench/benchMessagePackSerialization-opcache

scenario:PDOBench/benchPDOOverhead

scenario:PDOBench/benchPDOOverheadWithDBM

scenario:PHPRedisBench/benchRedisOverhead

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morrisonlevi commented Jun 10, 2026 •

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