feat(profiling): stack walks in timeline

[morrisonlevi]

This is a draft to add the time spent stack walking to the timeline and flame graphs.

Reviewer checklist

• Test coverage seems ok.
• Appropriate labels assigned.

[datadog-official]

⚠️ Tests

✨ Fix all issues with Cursor

⚠️ Warnings

🧪 1024 Tests failed

    testSearchPhpBinaries from integration.DDTrace\Tests\Integration\PHPInstallerTest (Fix with Cursor)

    testSimplePushAndProcess from laravel-58-test.DDTrace\Tests\Integrations\Laravel\V5_8\QueueTest (Fix with Cursor)

testSimplePushAndProcess from laravel-8x-test.DDTrace\Tests\Integrations\Laravel\V8_x\QueueTest (Datadog) (Fix with Cursor)

DDTrace\Tests\Integrations\Laravel\V8_x\QueueTest::testSimplePushAndProcess
Test code or tested code printed unexpected output: spanLinksTraceId: 6977c1de0000000065e148b96c7df5af
tid: 6977c1de00000000
hexProcessTraceId: 65e148b96c7df5af
hexProcessSpanId: 46fa8e2eafb653eb
processTraceId: 7341228828816962991
processSpanId: 5114556658000221163

View all

ℹ️ Info

❄️ No new flaky tests detected

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: dc0c9ca | Docs | Datadog PR Page | Was this helpful? Give us feedback!}

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 61.92%. Comparing base (4df27be) to head (0999c8b).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3591      +/-   ##
==========================================
+ Coverage   61.91%   61.92%   +0.01%     
==========================================
  Files         140      140              
  Lines       13312    13312              
  Branches     1762     1762              
==========================================
+ Hits         8242     8244       +2     
+ Misses       4280     4277       -3     
- Partials      790      791       +1     

see 1 file with indirect coverage changes

---

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[pr-commenter]

Benchmarks [ profiler ]

Benchmark execution time: 2026-01-26 19:25:06

Comparing candidate commit dc0c9ca in PR branch levi/stack-walk-in-timeline with baseline commit 4df27be in branch master.

Found 0 performance improvements and 9 performance regressions! Performance is the same for 18 metrics, 9 unstable metrics.

scenario:php-profiler-exceptions-with-profiler-and-timeline

• 🟥 cpu_usage_percentage [+4.381%; +5.329%]
• 🟥 execution_time [+3.353ms; +7.378ms] or [+3.524%; +7.756%]

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

• 🟥 cpu_usage_percentage [+7.177%; +10.369%]
• 🟥 cpu_user_time [+173.573ms; +228.446ms] or [+14.423%; +18.983%]
• 🟥 execution_time [+87.186ms; +99.120ms] or [+9.014%; +10.248%]

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

• 🟥 cpu_usage_percentage [+13.831%; +15.360%]
• 🟥 cpu_user_time [+612.456ms; +692.993ms] or [+38.048%; +43.051%]
• 🟥 execution_time [+402.573ms; +421.538ms] or [+31.685%; +33.178%]
• 🟥 max_rss_usage [+2.766MB; +3.437MB] or [+8.457%; +10.511%]