mirror of
https://github.com/golang/go
synced 2024-11-18 16:24:42 -07:00
e8c291b808
benchcmp now preserves benchmark order. This restores the original misc/benchcmp behavior. This also makes the output of benchcmp stable, and groups together multiple -cpu results. Magnitude-based sorting is still available via the -mag flag. It is useful for surfacing items of note (particularly changes in allocs) when making compiler changes and running broad benchmarks. Fixes golang/go#7259. LGTM=dave R=dave, mtj CC=bradfitz, dvyukov, golang-codereviews https://golang.org/cl/60840045
128 lines
3.0 KiB
Go
128 lines
3.0 KiB
Go
// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import (
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"bufio"
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"bytes"
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"fmt"
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"io"
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"strconv"
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"strings"
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)
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// Flags used by Bench.Measured to indicate
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// which measurements a Bench contains.
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const (
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NsOp = 1 << iota
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MbS
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BOp
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AllocsOp
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)
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// Bench is one run of a single benchmark.
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type Bench struct {
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Name string // benchmark name
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N int // number of iterations
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NsOp float64 // nanoseconds per iteration
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MbS float64 // MB processed per second
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BOp uint64 // bytes allocated per iteration
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AllocsOp uint64 // allocs per iteration
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Measured int // which measurements were recorded
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ord int // ordinal position within a benchmark run, used for sorting
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}
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// ParseLine extracts a Bench from a single line of testing.B output.
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func ParseLine(line string) (*Bench, error) {
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fields := strings.Fields(line)
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// Two required, positional fields: Name and iterations.
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if len(fields) < 2 {
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return nil, fmt.Errorf("two fields required, have %d", len(fields))
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}
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if !strings.HasPrefix(fields[0], "Benchmark") {
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return nil, fmt.Errorf(`first field does not start with "Benchmark`)
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}
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n, err := strconv.Atoi(fields[1])
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if err != nil {
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return nil, err
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}
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b := &Bench{Name: fields[0], N: n}
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// Parse any remaining pairs of fields; we've parsed one pair already.
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for i := 1; i < len(fields)/2; i++ {
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b.parseMeasurement(fields[i*2], fields[i*2+1])
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}
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return b, nil
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}
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func (b *Bench) parseMeasurement(quant string, unit string) {
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switch unit {
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case "ns/op":
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if f, err := strconv.ParseFloat(quant, 64); err == nil {
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b.NsOp = f
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b.Measured |= NsOp
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}
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case "MB/s":
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if f, err := strconv.ParseFloat(quant, 64); err == nil {
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b.MbS = f
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b.Measured |= MbS
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}
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case "B/op":
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if i, err := strconv.ParseUint(quant, 10, 64); err == nil {
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b.BOp = i
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b.Measured |= BOp
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}
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case "allocs/op":
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if i, err := strconv.ParseUint(quant, 10, 64); err == nil {
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b.AllocsOp = i
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b.Measured |= AllocsOp
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}
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}
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}
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func (b *Bench) String() string {
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buf := new(bytes.Buffer)
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fmt.Fprintf(buf, "%s %d", b.Name, b.N)
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if b.Measured&NsOp != 0 {
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fmt.Fprintf(buf, " %.2f ns/op", b.NsOp)
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}
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if b.Measured&MbS != 0 {
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fmt.Fprintf(buf, " %.2f MB/s", b.MbS)
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}
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if b.Measured&BOp != 0 {
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fmt.Fprintf(buf, " %d B/op", b.BOp)
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}
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if b.Measured&AllocsOp != 0 {
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fmt.Fprintf(buf, " %d allocs/op", b.AllocsOp)
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}
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return buf.String()
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}
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// BenchSet is a collection of benchmarks from one
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// testing.B run, keyed by name to faciliate comparison.
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type BenchSet map[string][]*Bench
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// Parse extracts a BenchSet from testing.B output. Parse
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// preserves the order of benchmarks that have identical names.
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func ParseBenchSet(r io.Reader) (BenchSet, error) {
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bb := make(BenchSet)
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scan := bufio.NewScanner(r)
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ord := 0
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for scan.Scan() {
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if b, err := ParseLine(scan.Text()); err == nil {
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b.ord = ord
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bb[b.Name] = append(bb[b.Name], b)
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ord++
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}
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}
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if err := scan.Err(); err != nil {
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return nil, err
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}
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return bb, nil
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}
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