Hi,
I have this program (https://play.golang.org/p/qHPzjj2uj3) that take a
decent amount of time for computing.
Let’s open pprof and see what it spent its time on.
Type: cpu
Time: Nov 15, 2017 at 5:48pm (CET)
Duration: 9.92s, Total samples = 9.78s (98.54%)
Entering interactive mode (type "help" for commands, "o" for options)
(pprof) list main.main
Total: 9.78s
ROUTINE ======================== main.main in
c:\Users\lemoussel\go\src\C-Libraries\main.go
80ms 9.78s (flat, cum) 100% of Total
. . 170: bufferHexHash, err := HexToUint32(hash,
binary.BigEndian)
. . 171: /*for i, val := range bufferHexHash {
. . 172: fmt.Printf("bufferHexHash[%d]: %08x
\n", i, val)
. . 173: }*/
. . 174: startTime = time.Now()
20ms 20ms 175: for i := 0; i < 10000000; i++ {
60ms 9.76s 176: result = findHex(bufferHexSearch,
bufferHexHash)
. . 177: }
. . 178: fmt.Printf("findHex() Find:
%t Time : %.2f sec.\n", result, time.Now().Sub(startTime).Seconds())
. . 179:}
Ok, so it seems we spent most of the time in findHex, makes sense!
(pprof) list main.findHex
Total: 9.78s
ROUTINE ======================== main.findHex in
c:\Users\lemoussel\go\src\C-Libraries\main.go
9.52s 9.52s (flat, cum) 97.34% of Total
. . 72: {0x00000fff, 0xfffffff0, 0x0}, // 5
. . 73: {0x000000ff, 0xffffffff, 0x0}, // 6
. . 74: {0x0000000f, 0xffffffff, 0xf0000000}, // 7
. . 75:}
. . 76:
20ms 20ms 77:func findHex(bufferHexSearch [8][3]uint32,
bufferHexHash []uint32) bool {
. . 78: var bFind = false
. . 79: var i, j, k int
. . 80: var lenBufferHexHash = len(bufferHexHash)
. . 81: var lenBufferHexSearch =
len(bufferHexSearch)
. . 82: var lenMaskHex = len(maskHex)
. . 83:LoopSearch:
300ms 300ms 84: for i = 0; i < lenBufferHexHash; i++ {
410ms 410ms 85: for j = 0; j < lenBufferHexSearch;
j++ {
2.53s 2.53s 86: for k = 0; k < lenMaskHex;
k++ {
6.16s 6.16s 87: if
bufferHexSearch[j][0] == bufferHexHash[i]&maskHex[k][0] &&
100ms 100ms 88:
bufferHexSearch[j][1] == bufferHexHash[i+1]&maskHex[k][1] {
. . 89: bFind = true
. . 90: break
LoopSearch
. . 91: }
. . 92: }
. . 93: }
Oh ! most of the time is in the line if bufferHexSearch[j][0] ==
bufferHexHash[i]&maskHex[k][0] &&
I don't understand why?
Should I use goroutine to compute concurrently?
I'm interested in any recommendations to optimize this program.
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