我偶然发现了a website making benchmakrs。在这种情况下Golang vs C ++,二叉树。
使用内存池分配,C ++解决方案比golang更好。我可以支持这一点,但想知道没有它的实施将如何实现。所以我修改它看起来更像Golang-Code并删除了两者的并发性。
在这个例子和我的机器上,golang代码在大约24秒内运行。 C ++代码平均需要126秒。我根本没想到这个结果。我预计C ++仍然会更快或者可能有点慢但不是5倍。
我犯了一些大错吗?或者你知道这个的原因吗?两个计划的代码如下:
内置:
mingw32-g ++。exe -Wall -fexceptions -O2 -c D:\ TMP \ Test \ main.cpp -o obj \ Release \ main.o mingw32-g ++。exe -o bin \ Release \ Test.exe obj \ Release \ main.o -s
#include <iostream>
using namespace std;
class Node {
public:
Node(uint64_t d);
~Node();
int Check();
private:
Node* l;
Node* r;
};
Node::Node(uint64_t d){
if (d > 0){
l = new Node(d - 1);
r = new Node(d - 1);
} else {
l = 0;
r = 0;
}
}
Node::~Node(){
if(l){
delete l;
delete r;
}
}
int Node::Check(){
if (l) {
return l->Check() + 1 + r->Check();
} else {
return 1;
}
}
int main()
{
uint64_t min_depth = 4;
uint64_t max_depth = 21;
for (uint64_t d = min_depth; d <= max_depth; d += 2) {
uint64_t iterations = 1 << (max_depth - d + min_depth);
uint64_t c = 0;
for (uint64_t i = 1; i < iterations; i++) {
Node* a = new Node(d);
c += a->Check();
delete a; // I tried commenting this line but it made no big impact
}
cout << iterations << " trees of depth " << d << " check: " << c << "\n";
}
return 0;
}
Golang:
去版本go1.7.1 windows / amd64
package main
import(
"fmt"
)
type Node struct {
l *Node
r *Node
}
func (n *Node) check() int {
if n.l != nil {
return n.l.check() + 1 + n.r.check()
} else {
return 1
}
}
func make(d uint) *Node {
root := new(Node)
if d > 0 {
root.l = make(d-1)
root.r = make(d-1)
}
return root
}
func main(){
min_depth := uint(4)
max_depth := uint(21)
for d := min_depth; d <= max_depth; d += 2 {
iterations := 1 << (max_depth - d + min_depth)
c := 0
for i := 1; i < iterations; i++ {
a := make(d)
c += a.check()
}
fmt.Println(iterations, " trees of depth ", d, " check: ", c)
}
}
这是你的计算机运行的东西,因为我得到了预期的结果,其中C ++的速度是前进的两倍。
C ++
time cmake-build-debug/main
2097152 trees of depth 4 check: 65011681
524288 trees of depth 6 check: 66584449
131072 trees of depth 8 check: 66977281
32768 trees of depth 10 check: 67074049
8192 trees of depth 12 check: 67092481
2048 trees of depth 14 check: 67074049
512 trees of depth 16 check: 66977281
128 trees of depth 18 check: 66584449
32 trees of depth 20 check: 65011681
cmake-build-debug/main 21.09s user 0.02s system 99% cpu 21.113 total
走
jonny@skyhawk ~/Projects/benchmark time ./main ✔ 2604 02:34:29
2097152 trees of depth 4 check: 65011681
524288 trees of depth 6 check: 66584449
131072 trees of depth 8 check: 66977281
32768 trees of depth 10 check: 67074049
8192 trees of depth 12 check: 67092481
2048 trees of depth 14 check: 67074049
512 trees of depth 16 check: 66977281
128 trees of depth 18 check: 66584449
32 trees of depth 20 check: 65011681
./main 48.72s user 0.52s system 197% cpu 24.905 total
我使用CLion的mose basic / default设置构建了C ++ main.cpp(这个CMakeLists.txt将构建一个main.cpp
)
cmake_minimum_required(VERSION 3.3)
project(test_build)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
set(BUILD_1 main)
set(SOURCE_FILES_1 main.cpp)
add_executable(${BUILD_1} ${SOURCE_FILES_1})