Skip to content
High resolution timing and benchmarking for Go
Branch: master
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Permalink
Type Name Latest commit message Commit time
Failed to load latest commit information.
_example
.gitignore benchtime: fix ps May 1, 2018
LICENSE
README.md
benchmark.go correct panic message Feb 23, 2019
benchmark_test.go make examples clearer about iteration count Feb 18, 2019
benchmarktsc.go
go.mod
go.sum
histogram.go
histogram_bounds.go
init.go
now.go
now_other.go
now_test.go
now_windows.go
stopwatch.go suppress staticcheck SA2001 Feb 26, 2019
stopwatch_test.go
stopwatchtsc.go
tsc.go
tsc_amd64.go
tsc_amd64.s
tsc_internal_test.go
tsc_other.go
tsc_test.go

README.md

hrtime

GoDoc

BETA QUALITY

Package hrtime implements high-resolution timing functions and benchmarking utilities.

hrtime relies on using the best timing mechanism on a particular system. At the moment, for Windows it is using Performance Counters and on other platforms standard time.Now (since it's good enough).

Package also supports using hardware time stamp counters (TSC). They offer better accuracy and on some platforms correspond to the processor cycles. However, they are not supported on all platforms.

For example measuring time.Sleep on Mac and Windows.

Example

package main

import (
    "fmt"
    "time"

    "github.com/loov/hrtime"
)

func main() {
    start := hrtime.Now()
    time.Sleep(1000 * time.Nanosecond)
    fmt.Println(hrtime.Since(start))

    const numberOfExperiments = 4096

    bench := hrtime.NewBenchmark(numberOfExperiments)
    for bench.Next() {
        time.Sleep(1000 * time.Nanosecond)
    }
    fmt.Println(bench.Histogram(10))
}

Output on Mac:

12µs
  avg 14.5µs;  min 2µs;  p50 12µs;  max 74µs;
  p90 22µs;  p99 44µs;  p999 69µs;  p9999 74µs;
        2µs [ 229] ██▌
       10µs [3239] ████████████████████████████████████████
       20µs [ 483] ██████
       30µs [  80] █
       40µs [  39] ▌
       50µs [  17] ▌
       60µs [   6]
       70µs [   3]
       80µs [   0]
       90µs [   0]

Output on Windows:

1.5155ms
  avg 1.49ms;  min 576µs;  p50 1.17ms;  max 2.47ms;
  p90 2.02ms;  p99 2.3ms;  p999 2.37ms;  p9999 2.47ms;
      577µs [   1]
      600µs [  57] █▌
      800µs [ 599] █████████████████
        1ms [1399] ████████████████████████████████████████
      1.2ms [  35] █
      1.4ms [   7]
      1.6ms [  91] ██▌
      1.8ms [ 995] ████████████████████████████
        2ms [ 778] ██████████████████████
      2.2ms [ 134] ███▌

A full explanation why it outputs this is out of the scope of this document. However, all sleep instructions have a specified granularity and time.Sleep actual sleeping time is requested time ± sleep granularity. There are also other explanations to that behavior.

You can’t perform that action at this time.