feat: HDR Histogram Implementation (TASK-400)#95
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copyleftdev merged 2 commits intomainfrom Jan 11, 2026
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Pure Zig implementation of High Dynamic Range Histogram for latency percentile calculations with bounded memory usage. Key features: - Configurable precision (1-5 significant figures) - Default config: 1ns to 1 hour range, 3 sig figs - Bounded memory (~260KB for default config) - O(1) value recording - Percentile queries: p0, p50, p90, p95, p99, p999, p100 - Tiger Style compliant (2+ assertions per function) 30 comprehensive unit tests covering: - Init/deinit and configuration validation - Value recording (single and batch) - Query functions (min, max, mean, totalCount) - Percentile accuracy on uniform and bimodal distributions - Memory bounds verification Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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Problem
TASK-400 requires HDR Histogram for accurate latency percentile calculations. The metrics system needs bounded memory usage regardless of sample count, with configurable precision for latency tracking from 1 nanosecond to 1 hour.
Solution
Pure Zig implementation of High Dynamic Range Histogram:
Testing
Changes
src/hdr_histogram.zig- HDR Histogram implementationtests/unit/hdr_histogram_test.zig- 30 unit testssrc/z6.zig- Export HdrHistogram and HdrError typesbuild.zig- Add test target🤖 Generated with Claude Code