Benchmarking result
$ go test -bench=.
goos: darwin
goarch: amd64
BenchmarkGrowZero-12 3067180 383 ns/op
BenchmarkGrowPreallocated-12 7515637 158 ns/op
PASS
ok _/Users/msmith/Desktop/test-alloc 4.059s
Created
November 18, 2019 16:36
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Append with preallocated capacity
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| package main | |
| import "fmt" | |
| func main() { | |
| GrowZero(true) | |
| GrowPreallocated(true) | |
| } | |
| func GrowZero(debug bool) { | |
| var a []int | |
| about(debug, a) | |
| for i := 0; i < 33; i++ { | |
| a = append(a, i) | |
| about(debug, a) | |
| } | |
| } | |
| func GrowPreallocated(debug bool) { | |
| a := make([]int, 0, 40) | |
| about(debug, a) | |
| for i := 0; i < 33; i++ { | |
| a = append(a, i) | |
| about(debug, a) | |
| } | |
| } | |
| func about(debug bool, a []int) { | |
| if debug { | |
| fmt.Printf("len=%d cap=%d %v\n", len(a), cap(a), a) | |
| } | |
| } |
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| package main | |
| import "testing" | |
| func BenchmarkGrowZero(b *testing.B) { | |
| // run the Fib function b.N times | |
| for n := 0; n < b.N; n++ { | |
| GrowZero(false) | |
| } | |
| } | |
| func BenchmarkGrowPreallocated(b *testing.B) { | |
| // run the Fib function b.N times | |
| for n := 0; n < b.N; n++ { | |
| GrowPreallocated(false) | |
| } | |
| } |
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