Struct hdrhistogram::Histogram [−] [src]

pub struct Histogram {
    // some fields omitted
}

Instance of a Histogram.

Methods

`impl Histogram`

`fn init(lowest_trackable_value: u64, highest_trackable_value: u64, significant_figures: u32) -> Result<Histogram>`

Create a new Histogram instance. lowest_trackable_value..highest_trackable_value defines the range of values in the Histogram. lowest_trackable_value must be >= 1. significant_figures defines the precision, and must be in the range 1..5.

HistogramErr is the catch-all failure case. It doesn't report much detail because the underlying library doesn't.

Example

let mut h = Histogram::init(1, 100000, 2).unwrap();
h.record_value(10);  // record a single count of '10'

`fn reset(&mut self)`

Zero all histogram state in place.

`fn record_value(&mut self, value: u64) -> bool`

Record a specific value. Returns true if successful.

h.record_value(5);
assert_eq!(h.total_count(), 1);

`fn record_values(&mut self, value: u64, count: u64) -> bool`

Record multiple counts of a specific value. Returns true if successful.

h.record_values(5, 10);
assert_eq!(h.total_count(), 10);

`fn record_corrected_value(&mut self, value: u64, expected_interval: u64) -> bool`

Record a value, correcting for coordinated omission. This should be used when accumulating latency measurements taked on a regular timebase (expected_interval). Any latency that's well above that interval implies some kind of outage in which sampled were lost. This corrects for those lost samples to preserve the integrity of the overall statistics.

`fn record_corrected_values(&mut self, value: u64, count: u64, expected_interval: u64) -> bool`

As with record_corrected_value() but multiple counts of the value.

`fn add(&mut self, other: &Histogram) -> u64`

Sum two histograms, modifying self in place. Returns the number of samples dropped; samples will be dropped if they're out of the range lowest_trackable_value .. highest_trackable_value.

`fn add_while_correcting_for_coordinated_omission(&mut self, other: &Histogram, expected_interval: u64) -> u64`

As with add but corrects of potential lost samples while doing periodic latency measurements, as in record_corrected_value. Only one correction should be applied.

`fn total_count(&self) -> u64`

Total of all counters

`fn min(&self) -> u64`

Smallest recorded value.

h.record_value(1);
h.record_value(5);
assert_eq!(h.min(), 1);

`fn max(&self) -> u64`

Largest recorded value.

h.record_value(1);
h.record_value(5);
assert_eq!(h.max(), 5);

`fn value_at_percentile(&self, percentile: f64) -> u64`

Value at a particular percentile (0-100).

h.record_values(20, 10);
h.record_value(40);
assert_eq!(h.value_at_percentile(50.0), 20);
assert_eq!(h.value_at_percentile(99.0), 40);

`fn stddev(&self) -> f64`

Standard deviation of values.

`fn mean(&self) -> f64`

Mean of values.

`fn values_are_equivalent(&self, a: u64, b: u64) -> bool`

Returns true if two values are the same according to the lowest, highest and significant figures parameters.

`fn lowest_equivalent_value(&self, value: u64) -> u64`

Lowest value equivalent to the given value.

`fn count_at_value(&self, value: u64) -> u64`

Count for a specific value.

`fn linear_iter<'a>(&'a self, value_units_per_bucket: u64) -> LinearIter<'a>`

Linear iterator over values. Results are returned in equally weighted buckets.

let mut h = Histogram::init(1, 100000, 3).unwrap();
for i in 1..100 { h.record_values(i, i); }
for (i, c) in h.linear_iter(1).enumerate() {    // 100 buckets
    println!("bucket {} = {}", i, c.count_added_in_this_iteration_step);
}

`fn log_iter<'a>(&'a self, value_units_per_bucket: u64, log_base: f64) -> LogIter<'a>`

Logarithmic iterator over values. Results are returned in logarithmically weighted buckets.

`fn recorded_iter<'a>(&'a self) -> RecordedIter<'a>`

Iterator over recorded values.

`fn percentile_iter<'a>(&'a self, ticks_per_half_distance: u32) -> PercentileIter<'a>`

Iterator over percentiles.

`fn encode(&self) -> Result<String>`

Encode Histogram state into a Base64 encoded string.

`fn decode(base64: &String) -> Result<Histogram>`

Decode Histogram state from a Base64 string generated by encode.