transport/http: make inbound header preallocation configurable - #2536
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bananacocodrilo wants to merge 2 commits into
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transport/http: make inbound header preallocation configurable#2536bananacocodrilo wants to merge 2 commits into
bananacocodrilo wants to merge 2 commits into
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Summary: Intent: - Preserve the default post-system-header sizing from PR #2521 while giving header-heavy services an escape hatch for requests dominated by unrelated HTTP headers. - Let downstream services choose the CPU and memory tradeoff that matches their inbound header mix. Changes: - Added remaining, scan, and disabled inbound header preallocation strategies through the Go API and HTTP transport configuration. - Made the opt-in scan count unique application, tracing, proxy, and grabbed headers, including collision and minimum-threshold handling. - Precomputed grabbed-header lookup keys per inbound so scanning adds no per-request allocations, with focused tests and benchmarks for each strategy. Jira Issues: T3-RPC-11408 --- <sub>Generated by the 🪄 [pr-create](https://sg.uberinternal.com/code.uber.internal/uber-code/devexp-agent-marketplace/-/blob/claude-code/plugins/dev/uber-dev/skills/pr-create/SKILL.md) skill in devexp-agent-marketplace</sub>
bananacocodrilo
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August 19, 2026 11:20
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Description
Intent:
Changes:
unfiltered,scan, anddisabledinbound header preallocation strategies through the Go API and HTTP transport configuration.unfilteredthe zero-value default; it uses the unfiltered number of request headers remaining after YARPC system headers are removed.Test Plan
go test ./transport/httpaifx verifygo test ./transport/http -run '^$' -bench '^BenchmarkFromHTTPHeadersCapacity/small/' -benchmem -benchtime=200ms -count=3Revert Plan
Revert this PR to restore PR #2521's unconditional post-system-header request-header-count preallocation.
Issues
T3-RPC-11408
RELEASE NOTES:
Added configurable inbound HTTP header preallocation strategies.