cpp-taskflow/taskflow/taskflow.hpp at master · ForgeMistress/cpp-taskflow · GitHub

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// MIT License

// Permission is hereby granted, free of charge, to any person obtaining a copy

// of this software and associated documentation files (the "Software"), to deal

// in the Software without restriction, including without limitation the rights

// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

// copies of the Software, and to permit persons to whom the Software is

// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all

// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

// SOFTWARE.

#pragma once

#include <iostream>

#include <mutex>

#include <deque>

#include <vector>

#include <algorithm>

#include <thread>

#include <future>

#include <functional>

#include <unordered_map>

#include <unordered_set>

#include <sstream>

#include <list>

#include <forward_list>

#include <numeric>

#include <iomanip>

#include <cassert>

#include <optional>

#include "threadpool/threadpool.hpp"

// ============================================================================

// Clang mis-interprets variant's get as a non-friend of variant and cannot

// get compiled correctly. We use the patch:

// https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=258854

// to get rid of this.

#if defined(__clang__)

#include "patch/clang_variant.hpp"

#else

#include <variant>

#endif

// ============================================================================

namespace tf {

// Procedure: throw_re

template <typename... ArgsT>

inline void throw_re(const char* fname, const size_t line, ArgsT&&... args) {

std::ostringstream oss(std::ios_base::out);

oss << '[' << fname << ':' << line << "] ";

(oss << ... << std::forward<ArgsT>(args));

throw std::runtime_error(oss.str());

}

#define TF_THROW(...) throw_re(__FILE__, __LINE__, __VA_ARGS__);

//-----------------------------------------------------------------------------

// Traits

//-----------------------------------------------------------------------------

// Macro to check whether a class has a member function

#define define_has_member(member_name) \

template <typename T> \

class has_member_##member_name \

{ \

typedef char yes_type; \

typedef long no_type; \

template <typename U> static yes_type test(decltype(&U::member_name)); \

template <typename U> static no_type test(...); \

public: \

static constexpr bool value = sizeof(test<T>(0)) == sizeof(yes_type); \

}

#define has_member(class_, member_name) has_member_##member_name<class_>::value

// Struct: dependent_false

template <typename... T>

struct dependent_false {

static constexpr bool value = false;

};

template <typename... T>

constexpr auto dependent_false_v = dependent_false<T...>::value;

// Struct: is_iterator

template <typename T, typename = void>

struct is_iterator {

static constexpr bool value = false;

};

template <typename T>

struct is_iterator<

std::enable_if_t<!std::is_same_v<typename std::iterator_traits<T>::value_type, void>>

> {

static constexpr bool value = true;

};

template <typename T>

inline constexpr bool is_iterator_v = is_iterator<T>::value;

// Struct: is_iterable

template <typename T, typename = void>

struct is_iterable : std::false_type {

};

template <typename T>

struct is_iterable<T, std::void_t<decltype(std::declval<T>().begin()),

decltype(std::declval<T>().end())>>

: std::true_type {

};

template <typename T>

inline constexpr bool is_iterable_v = is_iterable<T>::value;

//-----------------------------------------------------------------------------

// Taskflow definition

//-----------------------------------------------------------------------------

// Forward declaration

class Node;

class Topology;

class Task;

class FlowBuilder;

class SubflowBuilder;

class Taskflow;

using Graph = std::forward_list<Node>;

// ----------------------------------------------------------------------------

// Class: Node

class Node {

friend class Task;

friend class Topology;

friend class Taskflow;

using StaticWork = std::function<void()>;

using DynamicWork = std::function<void(SubflowBuilder&)>;

public:

Node();

template <typename C>

explicit Node(C&&);

const std::string& name() const;

void precede(Node&);

size_t num_successors() const;

size_t num_dependents() const;

std::string dump() const;

private:

std::string _name;

std::variant<StaticWork, DynamicWork> _work;

std::vector<Node*> _successors;

std::atomic<int> _dependents;

std::optional<Graph> _subgraph;

Topology* _topology;

void _dump(std::ostream&) const;

};

// Constructor

inline Node::Node() {

_dependents.store(0, std::memory_order_relaxed);

_topology = nullptr;

}

// Constructor

template <typename C>

inline Node::Node(C&& c) : _work {std::forward<C>(c)} {

_dependents.store(0, std::memory_order_relaxed);

_topology = nullptr;

}

// Procedure: precede

inline void Node::precede(Node& v) {

_successors.push_back(&v);

v._dependents.fetch_add(1, std::memory_order_relaxed);

}

// Function: num_successors

inline size_t Node::num_successors() const {

return _successors.size();

}

// Function: dependents

inline size_t Node::num_dependents() const {

return _dependents.load(std::memory_order_relaxed);

}

// Function: name

inline const std::string& Node::name() const {

return _name;

}

// Function: dump

inline std::string Node::dump() const {

std::ostringstream os;

_dump(os);

return os.str();

}

// Function: _dump

inline void Node::_dump(std::ostream& os) const {

if(_name.empty()) os << '\"' << this << '\"';

else os << std::quoted(_name);

os << ";\n";

for(const auto s : _successors) {

if(_name.empty()) os << '\"' << this << '\"';

else os << std::quoted(_name);

os << " -> ";

if(s->name().empty()) os << '\"' << s << '\"';

else os << std::quoted(s->name());

os << ";\n";

}

if(_subgraph && !_subgraph->empty()) {

os << "subgraph cluster_";

if(_name.empty()) os << this;

else os << _name;

os << " {\n";

os << "label = \"Subflow_";

if(_name.empty()) os << this;

else os << _name;

os << "\";\n" << "color=blue\n";

for(const auto& n : *_subgraph) {

n._dump(os);

}

os << "}\n";

}

// ----------------------------------------------------------------------------

// class: Topology

class Topology {

friend class Taskflow;

public:

Topology(Graph&&);

std::string dump() const;

private:

Graph _graph;

std::shared_future<void> _future;

Node _source;

Node _target;

void _dump(std::ostream&) const;

};

// Constructor

inline Topology::Topology(Graph&& t) :

_graph(std::move(t)) {

_source._topology = this;

_target._topology = this;

std::promise<void> promise;

_future = promise.get_future().share();

_target._work = [p=MoC{std::move(promise)}] () mutable {

p.get().set_value();

};

// ensure the topology is connected

_source.precede(_target);

// Build the super source and super target.

for(auto& node : _graph) {

node._topology = this;

if(node.num_dependents() == 0) {

_source.precede(node);

}

if(node.num_successors() == 0) {

node.precede(_target);

}

// Procedure: _dump

inline void Topology::_dump(std::ostream& os) const {

assert(_source._subgraph->empty());

assert(_target._subgraph->empty());

os << "digraph Topology {\n"

<< _source.dump()

<< _target.dump();

for(const auto& node : _graph) {

os << node.dump();

}

os << "}\n";

}

// Function: dump

inline std::string Topology::dump() const {

std::ostringstream os;

_dump(os);

return os.str();

}

// ----------------------------------------------------------------------------

// Class: Task

class Task {

friend class FlowBuilder;

friend class Taskflow;

public:

Task() = default;

Task(Node&);

Task(const Task&);

Task(Task&&);

Task& operator = (const Task&);

const std::string& name() const;

size_t num_successors() const;

size_t num_dependents() const;

Task& name(const std::string&);

Task& precede(Task);

Task& broadcast(std::vector<Task>&);

Task& broadcast(std::initializer_list<Task>);

Task& gather(std::vector<Task>&);

Task& gather(std::initializer_list<Task>);

template <typename C>

Task& work(C&&);

template <typename... Bs>

Task& broadcast(Bs&&...);

template <typename... Bs>

Task& gather(Bs&&...);

private:

Node* _node {nullptr};

template<typename S>

void _broadcast(S&);

template<typename S>

void _gather(S&);

};

// Constructor

inline Task::Task(Node& t) : _node {&t} {

}

// Constructor

inline Task::Task(const Task& rhs) : _node {rhs._node} {

}

// Function: precede

inline Task& Task::precede(Task tgt) {

_node->precede(*(tgt._node));

return *this;

}

// Function: broadcast

template <typename... Bs>

inline Task& Task::broadcast(Bs&&... tgts) {

(_node->precede(*(tgts._node)), ...);

return *this;

}

// Procedure: _broadcast

template <typename S>

inline void Task::_broadcast(S& tgts) {

for(auto& to : tgts) {

_node->precede(*(to._node));

}

// Function: broadcast

inline Task& Task::broadcast(std::vector<Task>& tgts) {

_broadcast(tgts);

return *this;

}

// Function: broadcast

inline Task& Task::broadcast(std::initializer_list<Task> tgts) {

_broadcast(tgts);

return *this;

}

// Function: gather

template <typename... Bs>

inline Task& Task::gather(Bs&&... tgts) {

(tgts.precede(*this), ...);

return *this;

}

// Procedure: _gather

template <typename S>

inline void Task::_gather(S& tgts) {

for(auto& from : tgts) {

from._node->precede(*_node);

}

// Function: gather

inline Task& Task::gather(std::vector<Task>& tgts) {

_gather(tgts);

return *this;

}

// Function: gather

inline Task& Task::gather(std::initializer_list<Task> tgts) {

_gather(tgts);

return *this;

}

// Operator =

inline Task& Task::operator = (const Task& rhs) {

_node = rhs._node;

return *this;

}

// Constructor

inline Task::Task(Task&& rhs) : _node{rhs._node} {

rhs._node = nullptr;

}

// Function: work

template <typename C>

inline Task& Task::work(C&& c) {

_node->_work = std::forward<C>(c);

return *this;

}

// Function: name

inline Task& Task::name(const std::string& name) {

_node->_name = name;

return *this;

}

// Function: name

inline const std::string& Task::name() const {

return _node->_name;

}

// Function: num_dependents

inline size_t Task::num_dependents() const {

return _node->_dependents.load(std::memory_order_relaxed);

}

// Function: num_successors

inline size_t Task::num_successors() const {

return _node->_successors.size();

}

// ----------------------------------------------------------------------------

// Class: FlowBuilder

class FlowBuilder {

public:

FlowBuilder(Graph&, size_t);

template <typename C>

auto emplace(C&&);

template <typename... C, std::enable_if_t<(sizeof...(C)>1), void>* = nullptr>

auto emplace(C&&...);

template <typename C>

auto silent_emplace(C&&);

template <typename... C, std::enable_if_t<(sizeof...(C)>1), void>* = nullptr>

auto silent_emplace(C&&...);

template <typename I, typename C>

auto parallel_for(I, I, C&&, size_t = 0);

template <typename T, typename C, std::enable_if_t<is_iterable_v<T>, void>* = nullptr>

auto parallel_for(T&, C&&, size_t = 0);

template <typename I, typename T, typename B>

auto reduce(I, I, T&, B&&);

template <typename I, typename T>

auto reduce_min(I, I, T&);

template <typename I, typename T>

auto reduce_max(I, I, T&);

template <typename I, typename T, typename B, typename U>

auto transform_reduce(I, I, T&, B&&, U&&);

template <typename I, typename T, typename B, typename P, typename U>

auto transform_reduce(I, I, T&, B&&, P&&, U&&);

auto placeholder();

void precede(Task, Task);

void linearize(std::vector<Task>&);

void linearize(std::initializer_list<Task>);

void broadcast(Task, std::vector<Task>&);

void broadcast(Task, std::initializer_list<Task>);

void gather(std::vector<Task>&, Task);

void gather(std::initializer_list<Task>, Task);

size_t size() const;

bool empty() const;

protected:

Graph& _graph;

size_t _partition_factor;

template <typename L>

void _linearize(L&);

};

inline FlowBuilder::FlowBuilder(Graph& graph, size_t f) :

_graph {graph},

_partition_factor {f} {

}

// Procedure: size

inline size_t FlowBuilder::size() const {

return std::distance(_graph.begin(), _graph.end());

}

// Function: empty

inline bool FlowBuilder::empty() const {

return _graph.empty();

}

// Procedure: precede

inline void FlowBuilder::precede(Task from, Task to) {

from._node->precede(*(to._node));

}

// Procedure: broadcast

inline void FlowBuilder::broadcast(Task from, std::vector<Task>& keys) {

from.broadcast(keys);

}

// Procedure: broadcast

inline void FlowBuilder::broadcast(

Task from, std::initializer_list<Task> keys

) {

from.broadcast(keys);

}

// Function: gather

inline void FlowBuilder::gather(

std::vector<Task>& keys, Task to

) {

to.gather(keys);

}

// Function: gather

inline void FlowBuilder::gather(

std::initializer_list<Task> keys, Task to

) {

to.gather(keys);

}

// Function: placeholder

inline auto FlowBuilder::placeholder() {

auto& node = _graph.emplace_front();

return Task(node);

}

// Function: silent_emplace

template <typename... C, std::enable_if_t<(sizeof...(C)>1), void>*>

inline auto FlowBuilder::silent_emplace(C&&... cs) {

return std::make_tuple(silent_emplace(std::forward<C>(cs))...);

}

// Function: parallel_for

template <typename I, typename C>

inline auto FlowBuilder::parallel_for(I beg, I end, C&& c, size_t g) {

using category = typename std::iterator_traits<I>::iterator_category;

if(g == 0) {

auto d = std::distance(beg, end);

auto w = std::max(size_t{1}, _partition_factor);

g = (d + w - 1) / w;

}

auto source = placeholder();

auto target = placeholder();

while(beg != end) {

auto e = beg;

// Case 1: random access iterator

if constexpr(std::is_same_v<category, std::random_access_iterator_tag>) {

size_t r = std::distance(beg, end);

std::advance(e, std::min(r, g));

}

// Case 2: non-random access iterator

else {

for(size_t i=0; i<g && e != end; ++e, ++i);

}

// Create a task

auto task = silent_emplace([beg, e, c] () mutable {

std::for_each(beg, e, c);

});

source.precede(task);

task.precede(target);

// adjust the pointer

beg = e;

}

return std::make_pair(source, target);

}

// Function: parallel_for

template <typename T, typename C, std::enable_if_t<is_iterable_v<T>, void>*>

inline auto FlowBuilder::parallel_for(T& t, C&& c, size_t group) {

return parallel_for(t.begin(), t.end(), std::forward<C>(c), group);

}

// Function: reduce_min

// Find the minimum element over a range of items.

template <typename I, typename T>

inline auto FlowBuilder::reduce_min(I beg, I end, T& result) {

return reduce(beg, end, result, [] (const auto& l, const auto& r) {

return std::min(l, r);

});

}

// Function: reduce_max

// Find the maximum element over a range of items.

template <typename I, typename T>

inline auto FlowBuilder::reduce_max(I beg, I end, T& result) {

return reduce(beg, end, result, [] (const auto& l, const auto& r) {

return std::max(l, r);

});

}

// Function: transform_reduce

template <typename I, typename T, typename B, typename U>

inline auto FlowBuilder::transform_reduce(

I beg, I end, T& result, B&& bop, U&& uop

) {

using category = typename std::iterator_traits<I>::iterator_category;

// Even partition

size_t d = std::distance(beg, end);

size_t w = std::max(size_t{1}, _partition_factor);

size_t g = std::max((d + w - 1) / w, size_t{2});

auto source = placeholder();

auto target = placeholder();

std::vector<std::future<T>> futures;

while(beg != end) {

auto e = beg;

// Case 1: random access iterator

if constexpr(std::is_same_v<category, std::random_access_iterator_tag>) {

size_t r = std::distance(beg, end);

std::advance(e, std::min(r, g));

}

// Case 2: non-random access iterator

else {

for(size_t i=0; i<g && e != end; ++e, ++i);

}

// Create a task

auto [task, future] = emplace([beg, e, bop, uop] () mutable {

auto init = uop(*beg);

for(++beg; beg != e; ++beg) {

init = bop(std::move(init), uop(*beg));

}

return init;

});

source.precede(task);

task.precede(target);

futures.push_back(std::move(future));

// adjust the pointer

beg = e;

}

// target synchronizer

target.work([&result, futures=MoC{std::move(futures)}, bop] () {

for(auto& fu : futures.object) {

result = bop(std::move(result), fu.get());

}

});

return std::make_pair(source, target);

}

// Function: transform_reduce

template <typename I, typename T, typename B, typename P, typename U>

inline auto FlowBuilder::transform_reduce(

I beg, I end, T& result, B&& bop, P&& pop, U&& uop

) {

using category = typename std::iterator_traits<I>::iterator_category;

// Even partition

size_t d = std::distance(beg, end);

size_t w = std::max(size_t{1}, _partition_factor);

size_t g = std::max((d + w - 1) / w, size_t{2});

auto source = placeholder();

auto target = placeholder();

std::vector<std::future<T>> futures;

while(beg != end) {

auto e = beg;

// Case 1: random access iterator

if constexpr(std::is_same_v<category, std::random_access_iterator_tag>) {

size_t r = std::distance(beg, end);

std::advance(e, std::min(r, g));

}

// Case 2: non-random access iterator

else {

for(size_t i=0; i<g && e != end; ++e, ++i);

}

// Create a task

auto [task, future] = emplace([beg, e, uop, pop] () mutable {

auto init = uop(*beg);

for(++beg; beg != e; ++beg) {

init = pop(std::move(init), *beg);

}

return init;

});

source.precede(task);

task.precede(target);

futures.push_back(std::move(future));

// adjust the pointer

beg = e;

}

// target synchronizer

target.work([&result, futures=MoC{std::move(futures)}, bop] () {

for(auto& fu : futures.object) {

result = bop(std::move(result), fu.get());

}

});

return std::make_pair(source, target);

}

// Procedure: _linearize

template <typename L>

inline void FlowBuilder::_linearize(L& keys) {

(void) std::adjacent_find(

keys.begin(), keys.end(),

[] (auto& from, auto& to) {

from._node->precede(*(to._node));

return false;

}

);

}

// Procedure: linearize

inline void FlowBuilder::linearize(std::vector<Task>& keys) {

_linearize(keys);

}

// Procedure: linearize

inline void FlowBuilder::linearize(std::initializer_list<Task> keys) {

_linearize(keys);

}

// Proceduer: reduce

template <typename I, typename T, typename B>

inline auto FlowBuilder::reduce(I beg, I end, T& result, B&& op) {

using category = typename std::iterator_traits<I>::iterator_category;

size_t d = std::distance(beg, end);

size_t w = std::max(size_t{1}, _partition_factor);

size_t g = std::max((d + w - 1) / w, size_t{2});

auto source = placeholder();

auto target = placeholder();

std::vector<std::future<T>> futures;

while(beg != end) {

auto e = beg;

// Case 1: random access iterator

if constexpr(std::is_same_v<category, std::random_access_iterator_tag>) {

size_t r = std::distance(beg, end);

std::advance(e, std::min(r, g));

}

// Case 2: non-random access iterator

else {

for(size_t i=0; i<g && e != end; ++e, ++i);

}

// Create a task

auto [task, future] = emplace([beg, e, op] () mutable {

auto init = *beg;

for(++beg; beg != e; ++beg) {

init = op(std::move(init), *beg);

}

return init;

});

source.precede(task);

task.precede(target);

futures.push_back(std::move(future));

// adjust the pointer

beg = e;

}

// target synchronizer

target.work([&result, futures=MoC{std::move(futures)}, op] () {

for(auto& fu : futures.object) {

result = op(std::move(result), fu.get());

}

});

return std::make_pair(source, target);

}

// ----------------------------------------------------------------------------

// Class: SubflowBuilder

class SubflowBuilder : public FlowBuilder {

public:

template <typename... Args>

SubflowBuilder(Args&&...);

void join();

void detach();

bool detached() const;

bool joined() const;

private:

bool _detached {false};

};

// Constructor

template <typename... Args>

inline SubflowBuilder::SubflowBuilder(Args&&... args) :

FlowBuilder {std::forward<Args>(args)...} {

}

// Procedure: join

inline void SubflowBuilder::join() {

_detached = false;

}

// Procedure: detach

inline void SubflowBuilder::detach() {

_detached = true;

}

// Function: detached

inline bool SubflowBuilder::detached() const {

return _detached;

}

// Function: joined

inline bool SubflowBuilder::joined() const {

return !_detached;

}

// Function: emplace

template <typename C>

inline auto FlowBuilder::emplace(C&& c) {

// subflow task

if constexpr(std::is_invocable_v<C, SubflowBuilder&>) {

using R = std::invoke_result_t<C, SubflowBuilder&>;

std::promise<R> p;

auto fu = p.get_future();

if constexpr(std::is_same_v<void, R>) {

auto& node = _graph.emplace_front([p=MoC(std::move(p)), c=std::forward<C>(c)]

(SubflowBuilder& fb) mutable {

if(fb._graph.empty()) {

c(fb);

if(fb.detached()) {

p.get().set_value();

}

else {

p.get().set_value();

}

});

return std::make_pair(Task(node), std::move(fu));

}

else {

auto& node = _graph.emplace_front(

[p=MoC(std::move(p)), c=std::forward<C>(c), r=std::optional<R>()]

(SubflowBuilder& fb) mutable {

if(fb._graph.empty()) {

r.emplace(c(fb));

if(fb.detached()) {

p.get().set_value(std::move(*r));

}

else {

assert(r);

p.get().set_value(std::move(*r));

}

});

return std::make_pair(Task(node), std::move(fu));

}

// regular task

else if constexpr(std::is_invocable_v<C>) {

using R = std::invoke_result_t<C>;

std::promise<R> p;

auto fu = p.get_future();

if constexpr(std::is_same_v<void, R>) {

auto& node = _graph.emplace_front(

[p=MoC(std::move(p)), c=std::forward<C>(c)]() mutable {

c();

p.get().set_value();

}

);

return std::make_pair(Task(node), std::move(fu));

}

else {

View remainder of file in raw view

cpp-taskflow/taskflow/taskflow.hpp at master · ForgeMistress/cpp-taskflow · GitHub

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