ParallelSearch/main.cpp

126 lines
3.0 KiB
C++

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <random>
#include <thread>
#include "SearchJob.hpp"
#include "TestRunner.hpp"
// Type of our hay stack: a list of strings
typedef std::vector<std::string> WordList;
typedef SearchJob<WordList::const_iterator> WordSearchJob;
typedef std::vector<WordSearchJob> SearchJobList;
void create_testdata(WordList& words)
{
const char start = 'A';
const char end = 'Z';
char str[4] = { 'A', 'A', 'A', 'A' };
for (str[0] = start; str[0] <= end; str[0]++)
for (str[1] = start; str[1] <= end; str[1]++)
for (str[2] = start; str[2] <= end; str[2]++)
for (str[3] = start; str[3] <= end; str[3]++)
words.push_back(std::string(str, 4));
}
void shuffle_testdata(WordList& words)
{
auto rng = std::default_random_engine{};
std::shuffle(words.begin(), words.end(), rng);
}
void run_wordsearch(WordSearchJob& job)
{
job.run();
}
void run_parallel_wordsearch(std::vector<WordSearchJob>& jobList)
{
std::vector<std::thread> threads;
for (WordSearchJob& job : jobList)
{
threads.push_back(std::thread(&WordSearchJob::run, &job));
}
for (std::thread& th : threads)
{
th.join();
}
}
int main()
{
double time_span;
std::string pattern = "ABC";
WordList test_data;
std::cout << "Hello World." << std::endl;
time_span = TestRunner(create_testdata, test_data);
std::cout << "It took me " << time_span << " seconds to create " << test_data.size() << " words." << std::endl;
time_span = TestRunner(shuffle_testdata, test_data);
std::cout << "It took me " << time_span << " seconds to shuffle " << test_data.size() << " words." << std::endl;
SearchJob<WordList::const_iterator> job(test_data.begin(), test_data.end(), pattern);
time_span = TestRunner(run_wordsearch, job);
std::cout << "It took me " << time_span << " seconds to find " << job.GetResult().size() << " matches." << std::endl;
std::vector<WordSearchJob> jobList;
unsigned coreCount = std::thread::hardware_concurrency();
std::size_t bucketSize = test_data.size() / coreCount;
std::size_t remains = test_data.size() % coreCount;
std::cout << "Creating " << coreCount << " search jobs, bucketSize = " << bucketSize << std::endl;
std::size_t offset = 0;
while(offset < test_data.size())
{
// compute [first; last( iterators for sub-range
std::size_t size = bucketSize + remains;
WordList::const_iterator first = test_data.begin() + offset;
WordList::const_iterator last = first + bucketSize + remains;
std::cout << "offset = " << offset << " size = " << size << std::endl;
// add appropriate search job
jobList.push_back(WordSearchJob(first, last, pattern));
// increment offset
offset += size;
// clear remains (it has been added to first bucket)
remains = 0;
}
time_span = TestRunner(run_parallel_wordsearch, jobList);
// collect search results ...
unsigned found = 0;
for (WordSearchJob& job : jobList)
{
found += job.GetResult().size();
}
std::cout << "It took me " << time_span << " seconds to find " << found << " matches." << std::endl;
std::cout << std::endl;
return 0;
}