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Diffstat (limited to 'libgo/go/testing/benchmark.go')
-rw-r--r--libgo/go/testing/benchmark.go232
1 files changed, 156 insertions, 76 deletions
diff --git a/libgo/go/testing/benchmark.go b/libgo/go/testing/benchmark.go
index 8dd8cbc..0e348be 100644
--- a/libgo/go/testing/benchmark.go
+++ b/libgo/go/testing/benchmark.go
@@ -8,23 +8,32 @@ import (
"flag"
"fmt"
"internal/race"
+ "io"
+ "math"
"os"
"runtime"
+ "sort"
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
+ "unicode"
)
-var matchBenchmarks = flag.String("test.bench", "", "run only benchmarks matching `regexp`")
-var benchTime = benchTimeFlag{d: 1 * time.Second}
-var benchmarkMemory = flag.Bool("test.benchmem", false, "print memory allocations for benchmarks")
-
-func init() {
+func initBenchmarkFlags() {
+ matchBenchmarks = flag.String("test.bench", "", "run only benchmarks matching `regexp`")
+ benchmarkMemory = flag.Bool("test.benchmem", false, "print memory allocations for benchmarks")
flag.Var(&benchTime, "test.benchtime", "run each benchmark for duration `d`")
}
+var (
+ matchBenchmarks *string
+ benchmarkMemory *bool
+
+ benchTime = benchTimeFlag{d: 1 * time.Second} // changed during test of testing package
+)
+
type benchTimeFlag struct {
d time.Duration
n int
@@ -101,10 +110,12 @@ type B struct {
// The net total of this test after being run.
netAllocs uint64
netBytes uint64
+ // Extra metrics collected by ReportMetric.
+ extra map[string]float64
}
// StartTimer starts timing a test. This function is called automatically
-// before a benchmark starts, but it can also used to resume timing after
+// before a benchmark starts, but it can also be used to resume timing after
// a call to StopTimer.
func (b *B) StartTimer() {
if !b.timerOn {
@@ -129,9 +140,19 @@ func (b *B) StopTimer() {
}
}
-// ResetTimer zeros the elapsed benchmark time and memory allocation counters.
+// ResetTimer zeroes the elapsed benchmark time and memory allocation counters
+// and deletes user-reported metrics.
// It does not affect whether the timer is running.
func (b *B) ResetTimer() {
+ if b.extra == nil {
+ // Allocate the extra map before reading memory stats.
+ // Pre-size it to make more allocation unlikely.
+ b.extra = make(map[string]float64, 16)
+ } else {
+ for k := range b.extra {
+ delete(b.extra, k)
+ }
+ }
if b.timerOn {
runtime.ReadMemStats(&memStats)
b.startAllocs = memStats.Mallocs
@@ -154,13 +175,6 @@ func (b *B) ReportAllocs() {
b.showAllocResult = true
}
-func (b *B) nsPerOp() int64 {
- if b.N <= 0 {
- return 0
- }
- return b.duration.Nanoseconds() / int64(b.N)
-}
-
// runN runs a single benchmark for the specified number of iterations.
func (b *B) runN(n int) {
benchmarkLock.Lock()
@@ -183,53 +197,20 @@ func (b *B) runN(n int) {
}
}
-func min(x, y int) int {
+func min(x, y int64) int64 {
if x > y {
return y
}
return x
}
-func max(x, y int) int {
+func max(x, y int64) int64 {
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, 3eX, 5eX].
-func roundUp(n int) int {
- base := roundDown10(n)
- switch {
- case n <= base:
- return base
- case n <= (2 * base):
- return 2 * base
- case n <= (3 * base):
- return 3 * base
- case n <= (5 * base):
- return 5 * base
- default:
- return 10 * base
- }
-}
-
// run1 runs the first iteration of benchFunc. It reports whether more
// iterations of this benchmarks should be run.
func (b *B) run1() bool {
@@ -312,23 +293,53 @@ func (b *B) launch() {
b.runN(b.benchTime.n)
} else {
d := b.benchTime.d
- for n := 1; !b.failed && b.duration < d && n < 1e9; {
+ for n := int64(1); !b.failed && b.duration < d && n < 1e9; {
last := n
// Predict required iterations.
- n = int(d.Nanoseconds())
- if nsop := b.nsPerOp(); nsop != 0 {
- n /= int(nsop)
+ goalns := d.Nanoseconds()
+ prevIters := int64(b.N)
+ prevns := b.duration.Nanoseconds()
+ if prevns <= 0 {
+ // Round up, to avoid div by zero.
+ prevns = 1
}
+ // Order of operations matters.
+ // For very fast benchmarks, prevIters ~= prevns.
+ // If you divide first, you get 0 or 1,
+ // which can hide an order of magnitude in execution time.
+ // So multiply first, then divide.
+ n = goalns * prevIters / prevns
// Run more iterations than we think we'll need (1.2x).
+ n += n / 5
// Don't grow too fast in case we had timing errors previously.
+ n = min(n, 100*last)
// Be sure to run at least one more than last time.
- n = max(min(n+n/5, 100*last), last+1)
- // Round up to something easy to read.
- n = roundUp(n)
- b.runN(n)
+ n = max(n, last+1)
+ // Don't run more than 1e9 times. (This also keeps n in int range on 32 bit platforms.)
+ n = min(n, 1e9)
+ b.runN(int(n))
}
}
- b.result = BenchmarkResult{b.N, b.duration, b.bytes, b.netAllocs, b.netBytes}
+ b.result = BenchmarkResult{b.N, b.duration, b.bytes, b.netAllocs, b.netBytes, b.extra}
+}
+
+// ReportMetric adds "n unit" to the reported benchmark results.
+// If the metric is per-iteration, the caller should divide by b.N,
+// and by convention units should end in "/op".
+// ReportMetric overrides any previously reported value for the same unit.
+// ReportMetric panics if unit is the empty string or if unit contains
+// any whitespace.
+// If unit is a unit normally reported by the benchmark framework itself
+// (such as "allocs/op"), ReportMetric will override that metric.
+// Setting "ns/op" to 0 will suppress that built-in metric.
+func (b *B) ReportMetric(n float64, unit string) {
+ if unit == "" {
+ panic("metric unit must not be empty")
+ }
+ if strings.IndexFunc(unit, unicode.IsSpace) >= 0 {
+ panic("metric unit must not contain whitespace")
+ }
+ b.extra[unit] = n
}
// The results of a benchmark run.
@@ -338,56 +349,122 @@ type BenchmarkResult struct {
Bytes int64 // Bytes processed in one iteration.
MemAllocs uint64 // The total number of memory allocations.
MemBytes uint64 // The total number of bytes allocated.
+
+ // Extra records additional metrics reported by ReportMetric.
+ Extra map[string]float64
}
+// NsPerOp returns the "ns/op" metric.
func (r BenchmarkResult) NsPerOp() int64 {
+ if v, ok := r.Extra["ns/op"]; ok {
+ return int64(v)
+ }
if r.N <= 0 {
return 0
}
return r.T.Nanoseconds() / int64(r.N)
}
+// mbPerSec returns the "MB/s" metric.
func (r BenchmarkResult) mbPerSec() float64 {
+ if v, ok := r.Extra["MB/s"]; ok {
+ return v
+ }
if r.Bytes <= 0 || r.T <= 0 || r.N <= 0 {
return 0
}
return (float64(r.Bytes) * float64(r.N) / 1e6) / r.T.Seconds()
}
-// AllocsPerOp returns r.MemAllocs / r.N.
+// AllocsPerOp returns the "allocs/op" metric,
+// which is calculated as r.MemAllocs / r.N.
func (r BenchmarkResult) AllocsPerOp() int64 {
+ if v, ok := r.Extra["allocs/op"]; ok {
+ return int64(v)
+ }
if r.N <= 0 {
return 0
}
return int64(r.MemAllocs) / int64(r.N)
}
-// AllocedBytesPerOp returns r.MemBytes / r.N.
+// AllocedBytesPerOp returns the "B/op" metric,
+// which is calculated as r.MemBytes / r.N.
func (r BenchmarkResult) AllocedBytesPerOp() int64 {
+ if v, ok := r.Extra["B/op"]; ok {
+ return int64(v)
+ }
if r.N <= 0 {
return 0
}
return int64(r.MemBytes) / int64(r.N)
}
+// String returns a summary of the benchmark results.
+// It follows the benchmark result line format from
+// https://golang.org/design/14313-benchmark-format, not including the
+// benchmark name.
+// Extra metrics override built-in metrics of the same name.
+// String does not include allocs/op or B/op, since those are reported
+// by MemString.
func (r BenchmarkResult) String() string {
- mbs := r.mbPerSec()
- mb := ""
- if mbs != 0 {
- mb = fmt.Sprintf("\t%7.2f MB/s", mbs)
- }
- nsop := r.NsPerOp()
- ns := fmt.Sprintf("%10d ns/op", nsop)
- if r.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(r.T.Nanoseconds())/float64(r.N))
- } else {
- ns = fmt.Sprintf("%12.1f ns/op", float64(r.T.Nanoseconds())/float64(r.N))
+ buf := new(strings.Builder)
+ fmt.Fprintf(buf, "%8d", r.N)
+
+ // Get ns/op as a float.
+ ns, ok := r.Extra["ns/op"]
+ if !ok {
+ ns = float64(r.T.Nanoseconds()) / float64(r.N)
+ }
+ if ns != 0 {
+ buf.WriteByte('\t')
+ prettyPrint(buf, ns, "ns/op")
+ }
+
+ if mbs := r.mbPerSec(); mbs != 0 {
+ fmt.Fprintf(buf, "\t%7.2f MB/s", mbs)
+ }
+
+ // Print extra metrics that aren't represented in the standard
+ // metrics.
+ var extraKeys []string
+ for k := range r.Extra {
+ switch k {
+ case "ns/op", "MB/s", "B/op", "allocs/op":
+ // Built-in metrics reported elsewhere.
+ continue
}
+ extraKeys = append(extraKeys, k)
+ }
+ sort.Strings(extraKeys)
+ for _, k := range extraKeys {
+ buf.WriteByte('\t')
+ prettyPrint(buf, r.Extra[k], k)
+ }
+ return buf.String()
+}
+
+func prettyPrint(w io.Writer, x float64, unit string) {
+ // Print all numbers with 10 places before the decimal point
+ // and small numbers with three sig figs.
+ var format string
+ switch y := math.Abs(x); {
+ case y == 0 || y >= 99.95:
+ format = "%10.0f %s"
+ case y >= 9.995:
+ format = "%12.1f %s"
+ case y >= 0.9995:
+ format = "%13.2f %s"
+ case y >= 0.09995:
+ format = "%14.3f %s"
+ case y >= 0.009995:
+ format = "%15.4f %s"
+ case y >= 0.0009995:
+ format = "%16.5f %s"
+ default:
+ format = "%17.6f %s"
}
- return fmt.Sprintf("%8d\t%s%s", r.N, ns, mb)
+ fmt.Fprintf(w, format, x, unit)
}
// MemString returns r.AllocedBytesPerOp and r.AllocsPerOp in the same format as 'go test'.
@@ -680,9 +757,12 @@ func (b *B) SetParallelism(p int) {
}
}
-// Benchmark benchmarks a single function. Useful for creating
+// Benchmark benchmarks a single function. It is useful for creating
// custom benchmarks that do not use the "go test" command.
//
+// If f depends on testing flags, then Init must be used to register
+// those flags before calling Benchmark and before calling flag.Parse.
+//
// If f calls Run, the result will be an estimate of running all its
// subbenchmarks that don't call Run in sequence in a single benchmark.
func Benchmark(f func(b *B)) BenchmarkResult {
generated by cgit v1.1 at 2025-04-13 03:57:00 +0000