Created
March 7, 2017 15:56
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go byte array benchmark
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package main | |
import ( | |
"fmt" | |
"time" | |
"unsafe" | |
"math" | |
"math/rand" | |
) | |
const times = 15000000000 | |
var buf = make([]byte, rand.Intn(10)) | |
var byteHolder byte | |
func testGetFloat64() time.Duration { | |
ts := time.Now() | |
var f64 float64 | |
for i := 0; i < times; i++ { | |
// seems got passed boundary check this way, faster than &buf[x] | |
// not familiar with golang though... | |
pt := uintptr(unsafe.Pointer(&buf)) + unsafe.Sizeof(byteHolder) * 3 | |
p := (*float64)(unsafe.Pointer(pt)) | |
f64 = *p | |
} | |
fmt.Println(f64) | |
te := time.Now() | |
return te.Sub(ts) | |
} | |
func testSetFloat64() time.Duration { | |
ts := time.Now() | |
var f64 float64 | |
f64 = 10.7 | |
for i := 0; i < times; i++ { | |
pt := uintptr(unsafe.Pointer(&buf)) + unsafe.Sizeof(byteHolder) * 3 | |
p := (*float64)(unsafe.Pointer(pt)) | |
*p = f64 | |
} | |
te := time.Now() | |
return te.Sub(ts) | |
} | |
func testGetFloat64Datum() time.Duration { | |
ts := time.Now() | |
var i64 int64 | |
i64 = 10 | |
var f64 float64 | |
for i := 0; i < times; i++ { | |
f64 = math.Float64frombits(uint64(i64)) | |
} | |
f64 = f64 + 1.0 | |
te := time.Now() | |
return te.Sub(ts) | |
} | |
func testSetFloat64Datum() time.Duration { | |
ts := time.Now() | |
var kind byte | |
var i64 int64 | |
var f64 float64 | |
f64 = 10.0 | |
for i := 0; i < times; i++ { | |
kind = 1 | |
i64 = int64(math.Float64bits(f64)) | |
} | |
kind = kind + 1 | |
i64 = i64 + 1 | |
te := time.Now() | |
return te.Sub(ts) | |
} | |
func testGetInt64Datum() time.Duration { | |
var i64 int64 | |
var val int64 = int64(rand.Intn(88)) | |
ts := time.Now() | |
for i := 0; i < times; i++ { | |
i64 = val | |
} | |
i64 = i64 + 1 | |
te := time.Now() | |
return te.Sub(ts) | |
} | |
func testGetInt64() time.Duration { | |
ts := time.Now() | |
var i64 int64 | |
for i := 0; i < times; i++ { | |
// seems got passed boundary check this way, faster than &buf[x] | |
// not familiar with golang though... | |
pt := uintptr(unsafe.Pointer(&buf)) + unsafe.Sizeof(byteHolder) * 3 | |
p := (*int64)(unsafe.Pointer(pt)) | |
i64 = *p | |
} | |
i64 = i64 + 1 | |
te := time.Now() | |
return te.Sub(ts) | |
} | |
func main() { | |
fmt.Println("testSetFloat64: ") | |
fmt.Println(testSetFloat64()) | |
fmt.Println("testGetFloat64: ") | |
fmt.Println(testGetFloat64()) | |
fmt.Println("testSetFloat64Datum: ") | |
fmt.Println(testSetFloat64Datum()) | |
fmt.Println("testGetFloat64Datum: ") | |
fmt.Println(testGetFloat64Datum()) | |
fmt.Println("testGetInt64Datum: ") | |
fmt.Println(testGetInt64Datum()) | |
fmt.Println("testGetInt64: ") | |
fmt.Println(testGetInt64()) | |
} | |
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这样子玩unsafe.Pointer容易失控,Go毕竟不是C。
另外,这种对列存的数据库比较合适,而对行存的Row各个column编码并不一样,不容易紧凑的编码。