module Cryload::Histogram

Overview

HDR-style logarithmic histogram: ~1% relative precision from 1µs to 1h in a few thousand buckets instead of a dense linear array.

Two representations share the same bucket layout so they can be merged without conversion: Sparse is worker-local and lock-free, Dense is the global aggregate merged under the Stats mutex.

Defined in:

cryload/histogram.cr

Constant Summary

BUCKET_COUNT = ((Math.log(MAX_MS / MIN_MS)) / LOG_GROWTH).ceil.to_i + 1

GROWTH = 1.01

LOG_GROWTH = Math.log(GROWTH)

MAX_MS = 3600000.0

MIN_MS = 0.001

Class Method Summary

• .bucket_index(value_ms : Float64) : Int32
• .bucket_value(index : Int32) : Float64

  Geometric midpoint of the bucket, the best estimate for values in it.

Class Method Detail