Multi-threaded C ++ tutorial (b) measure thread execution time

Brief introduction

Prior to the use of multi-threading to achieve accelerated, speaking about my first thread execution method commonly used to measure time. The basic idea is to achieve a measure of function, including representatives executed up.

The basic syntax

#include<iostream>
#include<thread>
using namespace std;

using namespace std::chrono;                //增加引用空间
template<class T>
void measure(T&& func) {
	auto beg_t = system_clock::now();       //开始时间
	func();								    //执行函数
	auto end_t = system_clock::now();       //结束时间
	duration<double> diff = end_t - beg_t;
	printf("performTest total time: ");
	cout << diff.count()<<endl;
}
void func() {
	cout << "This is func thread " << endl;
	int s = 0;
	for (int i = 0; i < 5; i++)
		s += i;
}

int main() {
	measure(func);
}

Results of the

This is func thread
performTest total time: 0.0004911

Advanced version of the case: the use of lambda function to write compact executable some (see the election)

int main() {
	int limit = 50;
	measure([limit]() {           //方括号捕捉外部变量limit
		cout << "This is func thread " << endl;
		int s = 0;
		for (int i = 0; i < limit; i++)
			s += i;
		}
	);
}
void measure(T&& func){
	auto beg_t = system_clock::now();
	func();
	auto end_t = system_clock::now();
	duration<double> diff = end_t - beg_t;
	printf("PerformTest total time: ");
	cout << diff.count()<<endl;
}

to sum up

This chapter describes how to use the function to measure execution time measure, the next section describes the specific process be accelerated.

Reference material

Links: cpp little knowledge --lambda expression .
Links: Tips common measurement function of time .