Effiective Modern C++ Study 시작에 앞서 Concurrency API 에 대한 Preview

1. Effective Modern C++ Study
Concurrency API
(Preview)
윤석준 / C++ Korea

2. Overview
vector<vector<int>>
user-defined
literals thread_local
=default, =delete
atomic<T> auto f() -> int
array<T, N>
decltype
vector<LocalType>
noexcept
regex
initializer lists
constexpr
extern template
unordered_map<int, string>raw string literals
nullptr auto i = v.begin();
async
lambdas
[]{ foo(); }
template
aliases
unique_ptr<T>
shared_ptr<T>
weak_ptr<T>
thread, mutex
for (x : coll)
override,
final
variadic templates
template <typename T…>
function<>
promise<T>/future<T>
tuple<int, float, string>
strongly-typed enums
enum class E {…};
static_assert(x)
rvalue references
(move semantics)
delegating constructors
packaged_task<T>

3. Overview
vector<vector<int>>
user-defined
literals thread_local
=default, =delete
atomic<T> auto f() -> int
array<T, N>
decltype
vector<LocalType>
noexcept
regex
initializer lists
constexpr
extern template
unordered_map<int, string>raw string literals
nullptr auto i = v.begin();
async
lambdas
[]{ foo(); }
template
aliases
unique_ptr<T>
shared_ptr<T>
weak_ptr<T>
thread, mutex
for (x : coll)
override,
final
variadic templates
template <typename T…>
function<>
promise<T>/future<T>
tuple<int, float, string>
strongly-typed enums
enum class E {…};
static_assert(x)
rvalue references
(move semantics)
delegating constructors
packaged_task<T>

8. ① Core 내부 병렬 프로그래밍
② Thread 병렬 프로그래밍
③ Process 병렬 프로그래밍
④ GPGPU를 이용한 병렬 프로그래밍
SIMD
OpenMP, PPL, pthreads
MPI
CUDA, OpenCV

10. Concurrency API in Modern C++

11. - include
- using, namespace
지금부터 예제에서 생략할 내용들
#include <iostream>
#include <thread>
#include <future>
#include <chrono>
#include <utility>
using std::cout;
using std::endl;
using std::vector;
using std::promise;
using std::future;
using std::thread;
using std::ref;
using std::move;
using std::this_thread::get_id;
using std::this_thread::sleep_for;
using namespace std::chrono;

12.  #include <thread>
 join() : 종료까지 대기 : Blocking
 detach() : thead object 분리
 swap() : thread object 끼리 교환
 get_id() : thread id 확인
 sleep_for(), sleep_until(), yield()
 thread_local : 각 thread별로 따로 생성
http://msdn.microsoft.com/ko-kr/library/hh920601.aspx
System Level의 Thread 생성

13. thread t1([] // 생성과 동시에 실행
{
for (int i = 0; i < 5; i++)
{
cout << "Thread1[" << get_id() << "] : " << i << endl;
sleep_for(milliseconds(500));
}
});
thread t2; // 생성 후 특정시점에 실행
t2 = thread([]
{
seconds tick(1);
auto StartTime = system_clock::now();
for (int i = 0; i < 5; i++)
{
cout << "Thread2[" << get_id() << "] : " << i << endl;
sleep_until(StartTime + tick * i);
}
});
http://devluna.blogspot.kr/2014/12/thread.html
thread t3 = std::thread([](int nParam) // Parameter 추가
{
for (int i = 0; i < 5; i++)
cout << "Thread3[" << get_id() << "] : " << nParam << endl;
}, 4);

14.  #include <mutex>
 lock(), unlock(), try_lock() : mutex 동작제어
 lock_guard : mutex lock의 RAII pattern
 recursive_mutex : 중첩 lock 허용
 timed_mutex : timed_lock_for(), timed_lock_until()
 call_once() : 한번만 실행
http://msdn.microsoft.com/ko-kr/library/hh921447.aspx
Lock을 이용하여 Task간 동기화 구현

15.  #include <condition_variable>
 wait(), wait_for(), wait_until() : notify 대기
 notify_one(), notify_all() : wait 깨우기
http://msdn.microsoft.com/ko-kr/library/hh874752.aspx
mutex를 활용하여 task 간의 동기화

16.  #include <atomic>
 +, -, AND, OR, XOR 등 …
 atomic_exchange(), atomic_compare_exchange()
 Compiler 에 따라 Lock으로 동작 할 수도 있다.
http://msdn.microsoft.com/ko-kr/library/hh874894.aspx
Lock-free로 변수 하나에 대한 동기화

17.  #include <future>
 auto a = async(launch policy, Fn&& fn, ArgTypes&& … args);
a.get();
 std::launch::async : 가능할때 먼저 실행
 std::launch::deferred : get() 호출할 때 실행
http://msdn.microsoft.com/ko-kr/library/hh920568.aspx
비동기로 수행가능한 task 생성 후 이를 수행할 thread를
system에게 위임

18. void f2(const int arg) { cout << "f2(" << arg << ")" << endl; }
void f3(const int arg, int*pResult) { cout << "f3(" << arg << ")" << endl; *pResult = arg; }
int f4(const int arg) { cout << "f4(" << arg << ")" << endl; return arg; }
void main()
{
future<void> t1 = async([] { cout << "f1()" << endl; }); // lambda expression
auto t2 = async(f2, 10); // passing argument
int result = -1;
auto t3 = async(f3, 10, &result); // how to get the result
cout << "[T3 : before get()] Result = " << result << endl;
t1.get(); t2.get(); t3.get();
cout << "[T3 : after get()] Result = " << result << endl;
auto t4 = async(f4, 10); // return value
result = t4.get();
cout << "[T4 : ager get()] Result = " << result << endl;
}
http://devluna.blogspot.kr/2014/12/async.html

19.  #include <future>
http://msdn.microsoft.com/ko-kr/library/hh920535.aspx
task 간의 통신 방법

20. void GetTestVector(promise<vector<int>>& p, int p_nStart, int p_nNum)
{
cout << "GetTestVector : " << get_id() << endl;
vector<int> v;
for (int i = 0; i < p_nNum; ++i)
v.push_back(i + p_nStart);
p.set_value(move(v));
cout << "End of GetTestVector" << endl;
}
void PrintTestVector(future<vector<int>>& f, thread& t)
{
cout << "PrintTestVector : " << get_id() << endl;
auto result = f.get();
for (auto item : result)
cout << "Get Values : " << item << endl;
cout << "End of PrintTestVector" << endl;
}
http://devluna.blogspot.kr/2015/01/thread-async-promisefuture.html
void main()
{
promise<vector<int>> p;
future<vector<int>> f = p.get_future();
thread t;
thread t2(&PrintTestVector, ref(f), ref(t));
sleep_for(milliseconds(500));
t = thread(&GetTestVector, ref(p), 11, 7);
t.join();
t2.join();
}

21.  #include <future>
http://msdn.microsoft.com/ko-kr/library/hh920525.aspx
비동기로 실행할 함수를 넘기고 결과를 future로 받음

22. std::vector<int> GetTestVector(int p_nStart, int p_nNum)
{
vector<int> V;
for (int i = 0; i < p_nNum; ++i)
{
V.push_back(i + p_nStart);
}
return V;
}
void main()
{
packaged_task<vector<int>(int, int)> task(&GetTestVector);
future<vector<int>> f = task.get_future();
thread t(move(task), 21, 7);
t.detach();
auto result = f.get();
for (auto i : result)
{
cout << "Get Values : " << i << endl;
}
}
http://devluna.blogspot.kr/2015/01/thread-packagedtask.html

24. 감사합니다.
https://www.facebook.com/seokjoon.yun.9
http://devluna.blogspot.kr/