Implement stats computation

[bwoebi]

Uses SHM under the hood, with fallback to sending over the socket (very first payloads when tracer starts, until the sidecar creates the SHM file).

[datadog-datadog-prod-us1]

⚠️ Tests

✨ Fix all issues with BitsAI or with Cursor

⚠️ Warnings

🧪 13 Tests failed

testScenario with data set "A GET request with an exception" from custom-framework-autoloading-test.DDTrace\Tests\Integrations\Custom\Autoloaded\CommonScenariosTest.DDTrace\Tests\Integrations\Custom\Autoloaded\CommonScenariosTest::testScenario     (Fix with Cursor)

DDTrace\Tests\Integrations\Custom\Autoloaded\CommonScenariosTest::testScenario with data set "A GET request with an exception" (DDTrace\Tests\Frameworks\Util\Request\GetSpec Object (...), array(DDTrace\Tests\Common\SpanAssertion Object (...)))
web.request: Wrong value for 'error': Array
(
    [service] => web.request
    [name] => web.request
    [resource] => GET /error
    [type] => web
    [trace_id] => 5895295595325322749
    [span_id] => 7195827074425579103
    [parent_id] => 5895295595325322749
...

    testResponseStatusCodeError from integration.DDTrace\Tests\Integration\ResponseStatusCodeTest (Fix with Cursor)

tmp/build_extension/tests/ext/request-replayer/client_side_stats_peer_tags.phpt (Client-side SHM span stats include peer tags configured via agent info) from php.tmp.build_extension.tests.ext.request.replayer     (Fix with Cursor)

001- peer_tags: ["db.hostname:my-db-host"]
001+ Fatal error: Uncaught Exception: wait for stats timeout in tmp/build_extension/tests/ext/includes/request_replayer.inc:141
002+ Stack trace:
003+ #0 tmp/build_extension/tests/ext/request-replayer/client_side_stats_peer_tags.php(33): RequestReplayer->waitForStats(Object(Closure))
004+ #1 {main}
005+   thrown in tmp/build_extension/tests/ext/includes/request_replayer.inc on line 141

View all

ℹ️ Info

No other issues found (see more)

❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 60.65% (-0.03%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 9430a1c | Docs | Datadog PR Page | Was this helpful? React with 👍/👎 or give us feedback!}

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 68.79%. Comparing base (fd1ba67) to head (9430a1c).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3756      +/-   ##
==========================================
- Coverage   68.85%   68.79%   -0.07%     
==========================================
  Files         166      166              
  Lines       19015    19015              
  Branches     1792     1792              
==========================================
- Hits        13093    13081      -12     
- Misses       5111     5121      +10     
- Partials      811      813       +2     

Flag	Coverage Δ
helper-rust-integration	78.82% <ø> (ø)
helper-rust-unit	49.36% <ø> (ø)

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see 2 files with indirect coverage changes

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[pr-commenter]

Benchmarks [ tracer ]

Benchmark execution time: 2026-03-30 16:20:09

Comparing candidate commit 9430a1c in PR branch bob/shm-stats-computation with baseline commit fd1ba67 in branch master.

Found 1 performance improvements and 4 performance regressions! Performance is the same for 187 metrics, 2 unstable metrics.

scenario:SamplingRuleMatchingBench/benchRegexMatching1

• 🟥 execution_time [+65.939ns; +123.861ns] or [+4.538%; +8.524%]

scenario:SamplingRuleMatchingBench/benchRegexMatching2

• 🟥 execution_time [+91.586ns; +159.214ns] or [+6.314%; +10.976%]

scenario:SamplingRuleMatchingBench/benchRegexMatching3

• 🟥 execution_time [+82.120ns; +145.680ns] or [+5.608%; +9.948%]

scenario:SamplingRuleMatchingBench/benchRegexMatching4

• 🟥 execution_time [+81.738ns; +158.262ns] or [+5.598%; +10.838%]

scenario:TraceSerializationBench/benchSerializeTrace-opcache

• 🟩 execution_time [-16.600µs; -8.400µs] or [-4.741%; -2.399%]