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| author | Filip Gruszczyński <gruszczy@gmail.com> | 2017-03-15 20:11:30 -0700 |
|---|---|---|
| committer | Rob Pike <r@golang.org> | 2017-03-24 19:36:14 +0000 |
| commit | 0b9607d1d648ae77d2db86a991db4a1fe921dbd8 (patch) | |
| tree | 3ee71a3482420dd956c72904c97e6dc1bef7ac58 /src/encoding/gob/decode.go | |
| parent | f1e880386b668a26dd6b7afdea43c9041a917fa5 (diff) | |
| download | go-0b9607d1d648ae77d2db86a991db4a1fe921dbd8.tar.gz go-0b9607d1d648ae77d2db86a991db4a1fe921dbd8.zip | |
encoding/gob: Speedup map decoding by reducing the allocations.
The improvementis achieved in encoding/gob/decode.go decodeMap by
allocate keyInstr and elemInstr only once and pass it to
decodeIntoValue, instead of allocating a new instance on every loop
cycle.
name old time/op new time/op delta
DecodeComplex128Slice-8 64.2µs ±10% 62.2µs ± 8% ~ (p=0.686 n=4+4)
DecodeFloat64Slice-8 37.1µs ± 3% 36.5µs ± 5% ~ (p=0.343 n=4+4)
DecodeInt32Slice-8 33.7µs ± 3% 32.7µs ± 4% ~ (p=0.200 n=4+4)
DecodeStringSlice-8 59.7µs ± 5% 57.3µs ± 1% ~ (p=0.114 n=4+4)
DecodeInterfaceSlice-8 543µs ± 7% 497µs ± 3% ~ (p=0.057 n=4+4)
DecodeMap-8 3.78ms ± 8% 2.66ms ± 2% -29.69% (p=0.029 n=4+4)
Updates #19525
Change-Id: Iec5fa4530de76f0a70da5de8a129a567b4aa096e
Reviewed-on: https://go-review.googlesource.com/38317
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Diffstat (limited to 'src/encoding/gob/decode.go')
| -rw-r--r-- | src/encoding/gob/decode.go | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/src/encoding/gob/decode.go b/src/encoding/gob/decode.go index 92d9d3ef87..645aa71c38 100644 --- a/src/encoding/gob/decode.go +++ b/src/encoding/gob/decode.go @@ -542,12 +542,12 @@ func (dec *Decoder) decodeArray(state *decoderState, value reflect.Value, elemOp } // decodeIntoValue is a helper for map decoding. -func decodeIntoValue(state *decoderState, op decOp, isPtr bool, value reflect.Value, ovfl error) reflect.Value { - instr := &decInstr{op, 0, nil, ovfl} +func decodeIntoValue(state *decoderState, op decOp, isPtr bool, value reflect.Value, instr *decInstr) reflect.Value { v := value if isPtr { v = decAlloc(value) } + op(instr, state, v) return value } @@ -564,9 +564,11 @@ func (dec *Decoder) decodeMap(mtyp reflect.Type, state *decoderState, value refl n := int(state.decodeUint()) keyIsPtr := mtyp.Key().Kind() == reflect.Ptr elemIsPtr := mtyp.Elem().Kind() == reflect.Ptr + keyInstr := &decInstr{keyOp, 0, nil, ovfl} + elemInstr := &decInstr{elemOp, 0, nil, ovfl} for i := 0; i < n; i++ { - key := decodeIntoValue(state, keyOp, keyIsPtr, allocValue(mtyp.Key()), ovfl) - elem := decodeIntoValue(state, elemOp, elemIsPtr, allocValue(mtyp.Elem()), ovfl) + key := decodeIntoValue(state, keyOp, keyIsPtr, allocValue(mtyp.Key()), keyInstr) + elem := decodeIntoValue(state, elemOp, elemIsPtr, allocValue(mtyp.Elem()), elemInstr) value.SetMapIndex(key, elem) } } |