hdr-histogram

Overview

A Haskell implementation of HdrHistogram. It allows storing counts of observed values within a range, while maintaining precision to a configurable number of significant digits.

Example

{-# LANGUAGE DataKinds           #-}
{-# LANGUAGE ScopedTypeVariables #-}

import           Control.Monad             (forM_)
import qualified Data.HdrHistogram         as H
import qualified Data.HdrHistogram.Mutable as MH

vals :: [Int]
vals = undefined

-- Measure from 1ms to 1 hour, with 3 points of precision
type Config = H.Config 1 3600000 3

main :: IO ()
main = do
  h <- MH.new
  forM_ vals (MH.record h)
  (frozen :: H.Histogram Config Int Int) <- MH.freeze h
  print $ H.percentile frozen 50