117
edits
Changes
→Vtune Profiler Coding Excercise
The Profiler can typically (by default) takes a snapshot of the whole application. Although, there is functionality to have it focus on particular area within an application to analyze. It will provide a general program overview, while highlighting specific problematic areas. These problematic areas can then be further analyzed to improve performance.
= Vtune Profiler Coding Excercise in Practice = <pre> // concrt-omp-count-primes.cpp// compile with: /EHsc /openmp#include <ppl.h>#include <random>#include <array>#include <iostream> using namespace concurrency;using namespace std; // Determines whether the input value is prime.bool is_prime(int n){ if (n < 2) return false; for (int i = 2; i < n; ++i) { if ((n % i) == 0) return false; } return true;} // Uses OpenMP to compute the count of prime numbers in an array.void omp_count_primes(int* a, size_t size){ if (size == 0) return; size_t count = 0; #pragma omp parallel for for (int i = 0; i < static_cast<int>(size); ++i) { if (is_prime(a[i])) { #pragma omp atomic ++count; } } wcout << L"found " << count << L" prime numbers." << endl;} // Uses the Concurrency Runtime to compute the count of prime numbers in an array.void concrt_count_primes(int* a, size_t size){ if (size == 0) return; combinable<size_t> counts; parallel_for<size_t>(0, size, [&](size_t i) { if (is_prime(a[i])) { counts.local()++; } }); wcout << L"found " << counts.combine(plus<size_t>()) << L" prime numbers." << endl;} int wmain(){ // The length of the array. const size_t size = 1000000; // Create an array and initialize it with random values. int* a = new int[size]; mt19937 gen(42); for (size_t i = 0; i < size; ++i) { a[i] = gen(); } // Count prime numbers by using OpenMP and the Concurrency Runtime. wcout << L"Using OpenMP..." << endl; omp_count_primes(a, size); wcout << L"Using the Concurrency Runtime..." << endl; concrt_count_primes(a, size); delete[] a;} </pre>
==References==
