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Code Issues Releases Activity

Remove allocs from WriteFloat32/WriteFloat64

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The use of strconv.FormatFloat causes a string allocation,
by setting aside a reusable buffer and using strconv.AppendFloat
this can be avoided.

Before:
BenchmarkRespond-4           300           5392189 ns/op          618936 B/op      20010 allocs/op

After:
BenchmarkRespond-4           300           4713746 ns/op          139744 B/op         10 allocs/op

This benchmark is using a custom encoder that calls WriteFloat64 20k
times, which is the bulk of the work.
This commit is contained in:
Brian Brazil
2018-02-07 17:30:57 +00:00
parent 002b5ae342
commit 1e8e785321
2 changed files with 8 additions and 2 deletions
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8
feature_stream_float.go
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@ -21,7 +21,9 @@ func (stream *Stream) WriteFloat32(val float32) {
fmt = 'e'
}
}
stream.WriteRaw(strconv.FormatFloat(float64(val), fmt, -1, 32))
stream.floatBuf = strconv.AppendFloat(stream.floatBuf, float64(val), fmt, -1, 32)
stream.Write(stream.floatBuf)
stream.floatBuf = stream.floatBuf[:0]
}
// WriteFloat32Lossy write float32 to stream with ONLY 6 digits precision although much much faster
@ -63,7 +65,9 @@ func (stream *Stream) WriteFloat64(val float64) {
fmt = 'e'
}
}
stream.WriteRaw(strconv.FormatFloat(float64(val), fmt, -1, 64))
stream.floatBuf = strconv.AppendFloat(stream.floatBuf, float64(val), fmt, -1, 64)
stream.Write(stream.floatBuf)
stream.floatBuf = stream.floatBuf[:0]
}
// WriteFloat64Lossy write float64 to stream with ONLY 6 digits precision although much much faster