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// Copyright 2009 The Go 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 check
import (
"fmt"
"runtime"
"time"
)
var memStats runtime.MemStats
// testingB is a type passed to Benchmark functions to manage benchmark
// timing and to specify the number of iterations to run.
type timer struct {
start time.Time // Time test or benchmark started
duration time.Duration
N int
bytes int64
timerOn bool
benchTime time.Duration
// The initial states of memStats.Mallocs and memStats.TotalAlloc.
startAllocs uint64
startBytes uint64
// The net total of this test after being run.
netAllocs uint64
netBytes uint64
}
// StartTimer starts timing a test. This function is called automatically
// before a benchmark starts, but it can also used to resume timing after
// a call to StopTimer.
func (c *C) StartTimer() {
if !c.timerOn {
c.start = time.Now()
c.timerOn = true
runtime.ReadMemStats(&memStats)
c.startAllocs = memStats.Mallocs
c.startBytes = memStats.TotalAlloc
}
}
// StopTimer stops timing a test. This can be used to pause the timer
// while performing complex initialization that you don't
// want to measure.
func (c *C) StopTimer() {
if c.timerOn {
c.duration += time.Now().Sub(c.start)
c.timerOn = false
runtime.ReadMemStats(&memStats)
c.netAllocs += memStats.Mallocs - c.startAllocs
c.netBytes += memStats.TotalAlloc - c.startBytes
}
}
// ResetTimer sets the elapsed benchmark time to zero.
// It does not affect whether the timer is running.
func (c *C) ResetTimer() {
if c.timerOn {
c.start = time.Now()
runtime.ReadMemStats(&memStats)
c.startAllocs = memStats.Mallocs
c.startBytes = memStats.TotalAlloc
}
c.duration = 0
c.netAllocs = 0
c.netBytes = 0
}
// SetBytes informs the number of bytes that the benchmark processes
// on each iteration. If this is called in a benchmark it will also
// report MB/s.
func (c *C) SetBytes(n int64) {
c.bytes = n
}
func (c *C) nsPerOp() int64 {
if c.N <= 0 {
return 0
}
return c.duration.Nanoseconds() / int64(c.N)
}
func (c *C) mbPerSec() float64 {
if c.bytes <= 0 || c.duration <= 0 || c.N <= 0 {
return 0
}
return (float64(c.bytes) * float64(c.N) / 1e6) / c.duration.Seconds()
}
func (c *C) timerString() string {
if c.N <= 0 {
return fmt.Sprintf("%3.3fs", float64(c.duration.Nanoseconds())/1e9)
}
mbs := c.mbPerSec()
mb := ""
if mbs != 0 {
mb = fmt.Sprintf("\t%7.2f MB/s", mbs)
}
nsop := c.nsPerOp()
ns := fmt.Sprintf("%10d ns/op", nsop)
if c.N > 0 && nsop < 100 {
// The format specifiers here make sure that
// the ones digits line up for all three possible formats.
if nsop < 10 {
ns = fmt.Sprintf("%13.2f ns/op", float64(c.duration.Nanoseconds())/float64(c.N))
} else {
ns = fmt.Sprintf("%12.1f ns/op", float64(c.duration.Nanoseconds())/float64(c.N))
}
}
memStats := ""
if c.benchMem {
allocedBytes := fmt.Sprintf("%8d B/op", int64(c.netBytes)/int64(c.N))
allocs := fmt.Sprintf("%8d allocs/op", int64(c.netAllocs)/int64(c.N))
memStats = fmt.Sprintf("\t%s\t%s", allocedBytes, allocs)
}
return fmt.Sprintf("%8d\t%s%s%s", c.N, ns, mb, memStats)
}
func min(x, y int) int {
if x > y {
return y
}
return x
}
func max(x, y int) int {
if x < y {
return y
}
return x
}
// roundDown10 rounds a number down to the nearest power of 10.
func roundDown10(n int) int {
var tens = 0
// tens = floor(log_10(n))
for n > 10 {
n = n / 10
tens++
}
// result = 10^tens
result := 1
for i := 0; i < tens; i++ {
result *= 10
}
return result
}
// roundUp rounds x up to a number of the form [1eX, 2eX, 5eX].
func roundUp(n int) int {
base := roundDown10(n)
if n < (2 * base) {
return 2 * base
}
if n < (5 * base) {
return 5 * base
}
return 10 * base
}
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