Struct Histogram 

pub struct Histogram { /* private fields */ }

A histogram of durations in microseconds.

Power-of-two buckets so that recording is leading_zeros and a fetch-add: no locks, no allocation, and no comparison chain. The bound this trades away is resolution — a value is placed within a factor of two — which is the right trade for “is the fold suddenly slow”, and the wrong one for a billing meter. Nothing here is a billing meter.

Implementations

impl Histogram

pub fn record_us(&self, us: u64)

pub fn record(&self, d: Duration)

pub fn count(&self) -> u64

pub fn sum_us(&self) -> u64

pub fn mean_us(&self) -> f64

pub fn bounds() -> Vec<f64>

The upper bound of each bucket, in microseconds — OTLP’s explicitBounds.

pub fn counts(&self) -> Vec<u64>

pub fn quantile_us(&self, q: f64) -> u64

The bucket at or below which q of the observations fall, as an upper bound in µs.

A bucketed estimate, not an exact quantile: with power-of-two buckets the true value is within a factor of two of what this returns, and saying “p99 is at most 4 ms” is the honest form of the claim.

Trait Implementations

impl Debug for Histogram

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Histogram

fn default() -> Self

Returns the “default value” for a type.