Crate histogram 

This crate provides histogram implementations that are conceptually similar to HdrHistogram, with modifications to the bucket construction and indexing algorithms that we believe provide a simpler implementation and more efficient runtime compared to the reference implementation of HdrHistogram.

Types

• Histogram — standard histogram with u64 counters. Use for single-threaded recording and percentile queries.
• AtomicHistogram — atomic histogram for concurrent recording. Take a snapshot with AtomicHistogram::load or AtomicHistogram::drain to query percentiles.
• SparseHistogram — compact representation storing only non-zero buckets. Useful for serialization and storage.

Example

use histogram::Histogram;

let mut h = Histogram::new(7, 64).unwrap();

for value in 1..=100 {
    h.increment(value).unwrap();
}

// Percentiles use the 0.0..=1.0 scale
let p50 = h.percentile(0.5).unwrap().unwrap();
let p99 = h.percentile(0.99).unwrap().unwrap();
// percentile() returns Result<Option<Bucket>, Error>
// outer unwrap: percentile value is valid
// inner unwrap: histogram is non-empty

println!("p50: {}-{}", p50.start(), p50.end());
println!("p99: {}-{}", p99.start(), p99.end());

Background

Please see: https://h2histogram.org

Structs

AtomicHistogram

A histogram that uses atomic 64bit counters for each bucket.

Bucket

A bucket represents a quantized range of values and a count of observations that fall into that range.

Config

The configuration of a histogram which determines the bucketing strategy and therefore the relative error and memory utilization of a histogram.

Histogram

A histogram that uses plain 64bit counters for each bucket.

SparseHistogram

A sparse, columnar representation of a histogram.

Enums

Error

Errors returned for histogram construction and operations.