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author | Martin Garton <garton@gmail.com> | 2019-09-30 09:27:38 +0000 |
---|---|---|
committer | Brad Fitzpatrick <bradfitz@golang.org> | 2019-11-08 18:35:59 +0000 |
commit | 7714dcacbca1961543fbad0c8bc2a2afc7baaaee (patch) | |
tree | 316f21c0286199ec5b556081360b869828238daf /src/encoding/binary | |
parent | 3e5c04313c28e463fa866c2ef669ed66628faf9b (diff) | |
download | go-7714dcacbca1961543fbad0c8bc2a2afc7baaaee.tar.gz go-7714dcacbca1961543fbad0c8bc2a2afc7baaaee.zip |
encoding/binary: add float support to fast path
This adds float type support to the main switch blocks in Read and
Write, instead of falling back to reflection. This gives a considerable
speedup for the float types:
ReadFloats-8 129ns ± 9% 70ns ± 8% -46.02% (p=0.001 n=7+7)
WriteFloats-8 131ns ± 6% 86ns ±11% -34.59% (p=0.001 n=7+7)
ReadSlice1000Float32s-8 14.6µs ±14% 4.8µs ±12% -67.29% (p=0.001 n=7+7)
WriteSlice1000Float32s-8 16.4µs ±20% 4.7µs ± 8% -71.01% (p=0.001 n=7+7)
Change-Id: I0be99d068b07d10dd6eb1137b45eff6f7c216b87
GitHub-Last-Rev: 4ff326e99ca35977d819f0ba29c10d9efc7e811c
GitHub-Pull-Request: golang/go#31803
Reviewed-on: https://go-review.googlesource.com/c/go/+/174959
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Diffstat (limited to 'src/encoding/binary')
-rw-r--r-- | src/encoding/binary/binary.go | 36 | ||||
-rw-r--r-- | src/encoding/binary/binary_test.go | 72 |
2 files changed, 108 insertions, 0 deletions
diff --git a/src/encoding/binary/binary.go b/src/encoding/binary/binary.go index 33066fc77a..a99ca01994 100644 --- a/src/encoding/binary/binary.go +++ b/src/encoding/binary/binary.go @@ -185,6 +185,10 @@ func Read(r io.Reader, order ByteOrder, data interface{}) error { *data = int64(order.Uint64(bs)) case *uint64: *data = order.Uint64(bs) + case *float32: + *data = math.Float32frombits(order.Uint32(bs)) + case *float64: + *data = math.Float64frombits(order.Uint64(bs)) case []bool: for i, x := range bs { // Easier to loop over the input for 8-bit values. data[i] = x != 0 @@ -219,6 +223,14 @@ func Read(r io.Reader, order ByteOrder, data interface{}) error { for i := range data { data[i] = order.Uint64(bs[8*i:]) } + case []float32: + for i := range data { + data[i] = math.Float32frombits(order.Uint32(bs[4*i:])) + } + case []float64: + for i := range data { + data[i] = math.Float64frombits(order.Uint64(bs[8*i:])) + } default: n = 0 // fast path doesn't apply } @@ -343,6 +355,22 @@ func Write(w io.Writer, order ByteOrder, data interface{}) error { for i, x := range v { order.PutUint64(bs[8*i:], x) } + case *float32: + order.PutUint32(bs, math.Float32bits(*v)) + case float32: + order.PutUint32(bs, math.Float32bits(v)) + case []float32: + for i, x := range v { + order.PutUint32(bs[4*i:], math.Float32bits(x)) + } + case *float64: + order.PutUint64(bs, math.Float64bits(*v)) + case float64: + order.PutUint64(bs, math.Float64bits(v)) + case []float64: + for i, x := range v { + order.PutUint64(bs[8*i:], math.Float64bits(x)) + } } _, err := w.Write(bs) return err @@ -696,6 +724,14 @@ func intDataSize(data interface{}) int { return 8 * len(data) case []uint64: return 8 * len(data) + case float32, *float32: + return 4 + case float64, *float64: + return 8 + case []float32: + return 4 * len(data) + case []float64: + return 8 * len(data) } return 0 } diff --git a/src/encoding/binary/binary_test.go b/src/encoding/binary/binary_test.go index 778de6908c..aeb4212ec2 100644 --- a/src/encoding/binary/binary_test.go +++ b/src/encoding/binary/binary_test.go @@ -634,3 +634,75 @@ func BenchmarkLittleEndianPutUint64(b *testing.B) { LittleEndian.PutUint64(putbuf[:], uint64(i)) } } + +func BenchmarkReadFloats(b *testing.B) { + var ls Struct + bsr := &byteSliceReader{} + var r io.Reader = bsr + b.SetBytes(4 + 8) + b.ResetTimer() + for i := 0; i < b.N; i++ { + bsr.remain = big[30:] + Read(r, BigEndian, &ls.Float32) + Read(r, BigEndian, &ls.Float64) + } + b.StopTimer() + want := s + want.Int8 = 0 + want.Int16 = 0 + want.Int32 = 0 + want.Int64 = 0 + want.Uint8 = 0 + want.Uint16 = 0 + want.Uint32 = 0 + want.Uint64 = 0 + want.Complex64 = 0 + want.Complex128 = 0 + want.Array = [4]uint8{0, 0, 0, 0} + want.Bool = false + want.BoolArray = [4]bool{false, false, false, false} + if b.N > 0 && !reflect.DeepEqual(ls, want) { + b.Fatalf("struct doesn't match:\ngot %v;\nwant %v", ls, want) + } +} + +func BenchmarkWriteFloats(b *testing.B) { + buf := new(bytes.Buffer) + var w io.Writer = buf + b.SetBytes(4 + 8) + b.ResetTimer() + for i := 0; i < b.N; i++ { + buf.Reset() + Write(w, BigEndian, s.Float32) + Write(w, BigEndian, s.Float64) + } + b.StopTimer() + if b.N > 0 && !bytes.Equal(buf.Bytes(), big[30:30+4+8]) { + b.Fatalf("first half doesn't match: %x %x", buf.Bytes(), big[30:30+4+8]) + } +} + +func BenchmarkReadSlice1000Float32s(b *testing.B) { + bsr := &byteSliceReader{} + slice := make([]float32, 1000) + buf := make([]byte, len(slice)*4) + b.SetBytes(int64(len(buf))) + b.ResetTimer() + for i := 0; i < b.N; i++ { + bsr.remain = buf + Read(bsr, BigEndian, slice) + } +} + +func BenchmarkWriteSlice1000Float32s(b *testing.B) { + slice := make([]float32, 1000) + buf := new(bytes.Buffer) + var w io.Writer = buf + b.SetBytes(4 * 1000) + b.ResetTimer() + for i := 0; i < b.N; i++ { + buf.Reset() + Write(w, BigEndian, slice) + } + b.StopTimer() +} |