tailscale/tstime/mono/mono_test.go

// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package mono

import (
	"testing"
	"time"
)

func TestNow(t *testing.T) {
	start := Now()
	time.Sleep(100 * time.Millisecond)
	if elapsed := Since(start); elapsed < 100*time.Millisecond {
		t.Errorf("short sleep: %v elapsed, want min %v", elapsed, 100*time.Millisecond)
	}
}

func BenchmarkMonoNow(b *testing.B) {
	for i := 0; i < b.N; i++ {
		Now()
	}
}

func BenchmarkTimeNow(b *testing.B) {
	for i := 0; i < b.N; i++ {
		time.Now()
	}
}
tstime/mono: new package Package mono provides a fast monotonic time. Its primary advantage is that it is fast: It is approximately twice as fast as time.Now. This is because time.Now uses two clock calls, one for wall time and one for monotonic time. We ask for the current time 4-6 times per network packet. At ~50ns per call to time.Now, that's enough to show up in CPU profiles. Package mono is a first step towards addressing that. It is designed to be a near drop-in replacement for package time. Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com> 3 years ago			`// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.`
			`// Use of this source code is governed by a BSD-style`
			`// license that can be found in the LICENSE file.`

			`package mono`

			`import (`
			`"testing"`
			`"time"`
			`)`

			`func TestNow(t *testing.T) {`
			`start := Now()`
			`time.Sleep(100 * time.Millisecond)`
			`if elapsed := Since(start); elapsed < 100*time.Millisecond {`
			`t.Errorf("short sleep: %v elapsed, want min %v", elapsed, 100*time.Millisecond)`
			`}`
			`}`

			`func BenchmarkMonoNow(b *testing.B) {`
			`for i := 0; i < b.N; i++ {`
			`Now()`
			`}`
			`}`

			`func BenchmarkTimeNow(b *testing.B) {`
			`for i := 0; i < b.N; i++ {`
			`time.Now()`
			`}`
			`}`