Created
December 19, 2013 20:56
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This is a small benchmark measuring fmt.Sscanf() abilities to parse an integer, vs. strconv.ParseInt(). Run with "go test -bench=." (no quotes) and see for yourself; results are amazing... Sscanf() is 40 times slower parsing a simple integer than ParseInt().
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| BenchmarkIntParse 50000000 57.1 ns/op | |
| BenchmarkIntScanf 1000000 1911 ns/op | |
| BenchmarkStrScanf 1000000 1675 ns/op |
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| package scanf | |
| import ( | |
| "fmt" | |
| "strconv" | |
| "testing" | |
| ) | |
| const str = "123423434" | |
| func BenchmarkIntParse(b *testing.B) { | |
| for i := 0; i < b.N; i++ { | |
| bn, err := strconv.ParseInt(str, 10, 0) | |
| if err != nil { | |
| b.Fatal(err) | |
| } | |
| // We convert to int just to have exactly the same result in both | |
| // tests, thus benchmarking equivalent functions. I'm using the extra | |
| // assignment to get rid of the "var unused" compiler error. Note, | |
| // however, that only the first assignment generates an actual | |
| // assembler instruction. So, there's no need to worry about skewing | |
| // the test by the weird n = n. | |
| n := int(bn) | |
| n = n | |
| } | |
| } | |
| func BenchmarkIntScanf(b *testing.B) { | |
| for i := 0; i < b.N; i++ { | |
| var n int | |
| if _, err := fmt.Sscanf(str, "%d", &n); err != nil { | |
| b.Fatal(err) | |
| } | |
| } | |
| } | |
| func BenchmarkStrScanf(b *testing.B) { | |
| for i := 0; i < b.N; i++ { | |
| var s string | |
| if _, err := fmt.Sscanf(str, "%s", &s); err != nil { | |
| b.Fatal(err) | |
| } | |
| } | |
| } |
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