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how slow is a mutex lock
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| /*************************************** | |
| Author: Gabriel Espinoza | |
| Desc: They say lock-based concurrency is slow | |
| let's test how slow is slow | |
| ***************************************/ | |
| #include <iostream> | |
| #include <mutex> | |
| #include <functional> | |
| #include <chrono> | |
| using namespace std; | |
| using namespace std::chrono; | |
| class C { | |
| int x{}; | |
| mutex m; | |
| public: | |
| void inc(){x++;} | |
| void safe_inc(){ | |
| lock_guard lk(m); | |
| x++; | |
| } | |
| }c; | |
| void run50000(function<void()> f) | |
| { | |
| auto start = steady_clock::now(); | |
| for( int i = 0; i < 50000; ++i) | |
| { | |
| f(); | |
| } | |
| cout << "run time " << duration_cast<nanoseconds>(steady_clock::now() - start) << endl ; | |
| } | |
| int main() | |
| { | |
| cout <<"running inc()\n"; | |
| run50000(bind(&C::inc,&c)); | |
| cout <<"running safe_inc()\n"; | |
| run50000(bind(&C::safe_inc,&c)); | |
| return 0; | |
| } |
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