56 lines
2.0 KiB
Go
56 lines
2.0 KiB
Go
package gotool
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import (
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"bytes"
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"io"
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"testing"
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)
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const performanceDiagnosticSize = 8 << 20
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func BenchmarkPerformanceCombinedOutput(b *testing.B) {
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for _, testCase := range []struct {
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name string
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size int
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chunkSize int
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}{
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{name: "modest", size: 4 << 10, chunkSize: 4 << 10},
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{name: "diagnostic-8MiB", size: performanceDiagnosticSize, chunkSize: performanceDiagnosticSize},
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{name: "diagnostic-8MiB-32KiB-chunks", size: performanceDiagnosticSize, chunkSize: 32 << 10},
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} {
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input := bytes.Repeat([]byte("go tool diagnostic output\n"), (testCase.size+25)/26)
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input = input[:testCase.size]
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b.Run(testCase.name+"/discard-forwarding", func(b *testing.B) {
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// Verify capture and forwarding for this workload outside the measurement.
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var forwarded bytes.Buffer
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verification := &combinedWriter{output: &forwarded}
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for offset := 0; offset < len(input); offset += testCase.chunkSize {
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chunk := input[offset:min(offset+testCase.chunkSize, len(input))]
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if written, err := verification.Write(chunk); err != nil || written != len(chunk) {
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b.Fatalf("verify output write = %d, err %v; want %d bytes", written, err, len(chunk))
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}
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}
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if !bytes.Equal(verification.take(), input) || !bytes.Equal(forwarded.Bytes(), input) {
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b.Fatal("captured and forwarded output must equal the complete input")
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}
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b.ReportAllocs()
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b.SetBytes(int64(len(input)))
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b.ResetTimer()
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b.ReportMetric(float64(len(input)), "bytes/op")
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for i := 0; i < b.N; i++ {
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writer := &combinedWriter{output: io.Discard}
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for offset := 0; offset < len(input); offset += testCase.chunkSize {
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chunk := input[offset:min(offset+testCase.chunkSize, len(input))]
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if written, err := writer.Write(chunk); err != nil || written != len(chunk) {
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b.Fatalf("write captured output = %d, err %v; want %d bytes", written, err, len(chunk))
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}
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}
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captured := writer.take()
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if len(captured) != len(input) {
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b.Fatalf("captured output = %d bytes, want %d", len(captured), len(input))
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}
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}
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})
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}
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}
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