[PROF-11789] Drop unknown leaf frames in VM stackwalker#394
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When native symbol resolution fails for the topmost frame, the VM stackwalker produces an "unknown" leaf. This breaks flame graph aggregation by lumping unrelated samples under a single entry. Extract the leaf-dropping logic into StackWalkValidation::dropUnknownLeaf() and call it at the end of walkVM(). Add gtest coverage for the new helper.
CI Test ResultsRun: #22309086671 | Commit:
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Legend: ✅ passed | ❌ failed | ⚪ skipped | 🚫 cancelled Summary: Total: 40 | Passed: 40 | Failed: 0 Updated: 2026-02-23 14:12:29 UTC |
jbachorik
approved these changes
Feb 23, 2026
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What does this PR do?:
Implement dropping empty/unknown leaf frames. The logic is in
StackWalkValidation::dropUnknownLeaf()and gets called at the end ofwalkVM(). Unit test for that leaf-dropping logic have been added.Motivation:
When leaf-nodes in stack-traces are 'unknown' (i.e. we have no method-ID), then those get aggregated in a single bucket in the pivot table, and is rather useless. We should avoid that to improve the quality of our stack-trace reporting.
Additional Notes:
How to test the change?:
For Datadog employees:
credentials of any kind, I've requested a review from
@DataDog/security-design-and-guidance.