我正在尝试使用不同的方法在golang中初始化/声明数组。我得到了不同的行为/结果。
go版本go1.3 darwin/amd64
版本1:
func main() {
a := [100000000]int64{}
var i int64
for i = 0; i < 100000000; i++ {
a[i] = i
}
}
生成一个763MB的二进制文件。当我运行它时,几秒钟后就会崩溃并显示以下信息:
运行时错误:goroutine堆栈超出1000000000字节限制
致命错误:堆栈溢出
版本2:
func main() {
var a [100000000]int64
var i int64
for i = 0; i < 100000000; i++ {
a[i] = i
}
}
产生一个456KB的二进制文件,运行时间不到一秒钟。
问题:
有人可以帮我理解为什么存在这些差异(和其他可能被忽略的差异)吗?谢谢!
编辑:
运行时间:
我构建了两个不同的代码片段并运行了编译版本,所以没有添加编译时间。虽然第一次运行version1非常慢。以下是输出结果。
go build version1.go
go build version2.go
以下是执行输出结果
版本 1
第一次运行
time ./version1
runtime: goroutine stack exceeds 1000000000-byte limit
fatal error: stack overflow
runtime stack:
runtime.throw(0x2fb42a8e)
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/panic.c:520 +0x69
runtime.newstack()
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/stack.c:770 +0x486
runtime.morestack()
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/asm_amd64.s:228 +0x61
goroutine 16 [stack growth]:
main.main()
/Users/ec/repo/offers/lol/version1.go:3 fp=0x2b7b85f50 sp=0x2b7b85f48
runtime.main()
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/proc.c:247 +0x11a fp=0x2b7b85fa8 sp=0x2b7b85f50
runtime.goexit()
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/proc.c:1445 fp=0x2b7b85fb0 sp=0x2b7b85fa8
created by _rt0_go
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/asm_amd64.s:97 +0x120
goroutine 17 [runnable]:
runtime.MHeap_Scavenger()
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/mheap.c:507
runtime.goexit()
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/proc.c:1445
./version1 0.00s user 0.10s system 1% cpu 7.799 total
第二次运行
runtime: goroutine stack exceeds 1000000000-byte limit
fatal error: stack overflow
runtime stack:
runtime.throw(0x2fb42a8e)
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/panic.c:520 +0x69
runtime.newstack()
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/stack.c:770 +0x486
runtime.morestack()
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/asm_amd64.s:228 +0x61
goroutine 16 [stack growth]:
main.main()
/Users/ec/repo/offers/lol/version1.go:3 fp=0x2b7b85f50 sp=0x2b7b85f48
runtime.main()
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/proc.c:247 +0x11a fp=0x2b7b85fa8 sp=0x2b7b85f50
runtime.goexit()
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/proc.c:1445 fp=0x2b7b85fb0 sp=0x2b7b85fa8
created by _rt0_go
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/asm_amd64.s:97 +0x120
goroutine 17 [runnable]:
runtime.MHeap_Scavenger()
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/mheap.c:507
runtime.goexit()
/usr/local/Cellar/go/1.3/libexec/src/pkg/runtime/proc.c:1445
./version1 0.00s user 0.10s system 98% cpu 0.102 total
版本 2
首次运行
time ./version2
./version2 0.16s user 0.26s system 99% cpu 0.429 total
第二次运行
time ./version2
./version2 0.17s user 0.25s system 97% cpu 0.421 total
go run
进行测试,并且时间差在于构建大型二进制文件。 - JimB