+++ /dev/null
-/* A thread pool (C++ version). */
-
-/* Copyright (c) 2004-2017 The SimGrid Team.
- * All rights reserved. */
-
-/* This program is free software; you can redistribute it and/or modify it
- * under the terms of the license (GNU LGPL) which comes with this package. */
-
-#ifndef XBT_PARMAP_HPP
-#define XBT_PARMAP_HPP
-
-#include "src/internal_config.h" // HAVE_FUTEX_H
-#include "src/kernel/context/Context.hpp"
-#include <atomic>
-#include <boost/optional.hpp>
-#include <simgrid/simix.h>
-#include <vector>
-#include <xbt/log.h>
-#include <xbt/parmap.h>
-#include <xbt/xbt_os_thread.h>
-
-#if HAVE_FUTEX_H
-#include <limits>
-#include <linux/futex.h>
-#include <sys/syscall.h>
-#endif
-
-XBT_LOG_EXTERNAL_CATEGORY(xbt_parmap);
-
-namespace simgrid {
-namespace xbt {
-
-/** \addtogroup XBT_parmap
- * \ingroup XBT_misc
- * \brief Parallel map class
- * \{
- */
-template <typename T> class Parmap {
-public:
- Parmap(unsigned num_workers, e_xbt_parmap_mode_t mode);
- Parmap(const Parmap&) = delete;
- ~Parmap();
- void apply(void (*fun)(T), const std::vector<T>& data);
- boost::optional<T> next();
-
-private:
- enum Flag { PARMAP_WORK, PARMAP_DESTROY };
-
- /**
- * \brief Thread data transmission structure
- */
- class ThreadData {
- public:
- ThreadData(Parmap<T>& parmap, int id) : parmap(parmap), worker_id(id) {}
- Parmap<T>& parmap;
- int worker_id;
- };
-
- /**
- * \brief Synchronization object (different specializations).
- */
- class Synchro {
- public:
- explicit Synchro(Parmap<T>& parmap) : parmap(parmap) {}
- virtual ~Synchro() = default;
- /**
- * \brief Wakes all workers and waits for them to finish the tasks.
- *
- * This function is called by the controller thread.
- */
- virtual void master_signal() = 0;
- /**
- * \brief Starts the parmap: waits for all workers to be ready and returns.
- *
- * This function is called by the controller thread.
- */
- virtual void master_wait() = 0;
- /**
- * \brief Ends the parmap: wakes the controller thread when all workers terminate.
- *
- * This function is called by all worker threads when they end (not including the controller).
- */
- virtual void worker_signal() = 0;
- /**
- * \brief Waits for some work to process.
- *
- * This function is called by each worker thread (not including the controller) when it has no more work to do.
- *
- * \param round the expected round number
- */
- virtual void worker_wait(unsigned) = 0;
-
- Parmap<T>& parmap;
- };
-
- class PosixSynchro : public Synchro {
- public:
- explicit PosixSynchro(Parmap<T>& parmap);
- ~PosixSynchro();
- void master_signal();
- void master_wait();
- void worker_signal();
- void worker_wait(unsigned round);
-
- private:
- xbt_os_cond_t ready_cond;
- xbt_os_mutex_t ready_mutex;
- xbt_os_cond_t done_cond;
- xbt_os_mutex_t done_mutex;
- };
-
-#if HAVE_FUTEX_H
- class FutexSynchro : public Synchro {
- public:
- explicit FutexSynchro(Parmap<T>& parmap) : Synchro(parmap) {}
- void master_signal();
- void master_wait();
- void worker_signal();
- void worker_wait(unsigned);
-
- private:
- static void futex_wait(unsigned* uaddr, unsigned val);
- static void futex_wake(unsigned* uaddr, unsigned val);
- };
-#endif
-
- class BusyWaitSynchro : public Synchro {
- public:
- explicit BusyWaitSynchro(Parmap<T>& parmap) : Synchro(parmap) {}
- void master_signal();
- void master_wait();
- void worker_signal();
- void worker_wait(unsigned);
- };
-
- static void* worker_main(void* arg);
- Synchro* new_synchro(e_xbt_parmap_mode_t mode);
- void work();
-
- Flag status; /**< is the parmap active or being destroyed? */
- unsigned work_round; /**< index of the current round */
- xbt_os_thread_t* workers; /**< worker thread handlers */
- unsigned num_workers; /**< total number of worker threads including the controller */
- Synchro* synchro; /**< synchronization object */
-
- unsigned thread_counter = 0; /**< number of workers that have done the work */
- void (*fun)(const T) = nullptr; /**< function to run in parallel on each element of data */
- const std::vector<T>* data = nullptr; /**< parameters to pass to fun in parallel */
- std::atomic<unsigned> index; /**< index of the next element of data to pick */
-};
-
-/**
- * \brief Creates a parallel map object
- * \param num_workers number of worker threads to create
- * \param mode how to synchronize the worker threads
- */
-template <typename T> Parmap<T>::Parmap(unsigned num_workers, e_xbt_parmap_mode_t mode)
-{
- XBT_CDEBUG(xbt_parmap, "Create new parmap (%u workers)", num_workers);
-
- /* Initialize the thread pool data structure */
- this->status = PARMAP_WORK;
- this->work_round = 0;
- this->workers = new xbt_os_thread_t[num_workers];
- this->num_workers = num_workers;
- this->synchro = new_synchro(mode);
-
- /* Create the pool of worker threads */
- this->workers[0] = nullptr;
-#if HAVE_PTHREAD_SETAFFINITY
- int core_bind = 0;
-#endif
- for (unsigned i = 1; i < num_workers; i++) {
- ThreadData* data = new ThreadData(*this, i);
- this->workers[i] = xbt_os_thread_create(nullptr, worker_main, data, nullptr);
-#if HAVE_PTHREAD_SETAFFINITY
- xbt_os_thread_bind(this->workers[i], core_bind);
- if (core_bind != xbt_os_get_numcores() - 1)
- core_bind++;
- else
- core_bind = 0;
-#endif
- }
-}
-
-/**
- * \brief Destroys a parmap
- */
-template <typename T> Parmap<T>::~Parmap()
-{
- status = PARMAP_DESTROY;
- synchro->master_signal();
-
- for (unsigned i = 1; i < num_workers; i++)
- xbt_os_thread_join(workers[i], nullptr);
-
- delete[] workers;
- delete synchro;
-}
-
-/**
- * \brief Applies a list of tasks in parallel.
- * \param fun the function to call in parallel
- * \param data each element of this vector will be passed as an argument to fun
- */
-template <typename T> void Parmap<T>::apply(void (*fun)(T), const std::vector<T>& data)
-{
- /* Assign resources to worker threads (we are maestro here)*/
- this->fun = fun;
- this->data = &data;
- this->index = 0;
- this->synchro->master_signal(); // maestro runs futex_wake to wake all the minions (the working threads)
- this->work(); // maestro works with its minions
- this->synchro->master_wait(); // When there is no more work to do, then maestro waits for the last minion to stop
- XBT_CDEBUG(xbt_parmap, "Job done"); // ... and proceeds
-}
-
-/**
- * \brief Returns a next task to process.
- *
- * Worker threads call this function to get more work.
- *
- * \return the next task to process, or throws a std::out_of_range exception if there is no more work
- */
-template <typename T> boost::optional<T> Parmap<T>::next()
-{
- unsigned index = this->index.fetch_add(1, std::memory_order_relaxed);
- if (index < this->data->size())
- return (*this->data)[index];
- else
- return boost::none;
-}
-
-/**
- * \brief Main work loop: applies fun to elements in turn.
- */
-template <typename T> void Parmap<T>::work()
-{
- unsigned length = this->data->size();
- unsigned index = this->index.fetch_add(1, std::memory_order_relaxed);
- while (index < length) {
- this->fun((*this->data)[index]);
- index = this->index.fetch_add(1, std::memory_order_relaxed);
- }
-}
-
-/**
- * Get a synchronization object for given mode.
- * \param mode the synchronization mode
- */
-template <typename T> typename Parmap<T>::Synchro* Parmap<T>::new_synchro(e_xbt_parmap_mode_t mode)
-{
- if (mode == XBT_PARMAP_DEFAULT) {
-#if HAVE_FUTEX_H
- mode = XBT_PARMAP_FUTEX;
-#else
- mode = XBT_PARMAP_POSIX;
-#endif
- }
- Synchro* res;
- switch (mode) {
- case XBT_PARMAP_POSIX:
- res = new PosixSynchro(*this);
- break;
- case XBT_PARMAP_FUTEX:
-#if HAVE_FUTEX_H
- res = new FutexSynchro(*this);
-#else
- xbt_die("Futex is not available on this OS.");
-#endif
- break;
- case XBT_PARMAP_BUSY_WAIT:
- res = new BusyWaitSynchro(*this);
- break;
- default:
- THROW_IMPOSSIBLE;
- }
- return res;
-}
-
-/**
- * \brief Main function of a worker thread.
- */
-template <typename T> void* Parmap<T>::worker_main(void* arg)
-{
- ThreadData* data = static_cast<ThreadData*>(arg);
- Parmap<T>& parmap = data->parmap;
- unsigned round = 0;
- smx_context_t context = SIMIX_context_new(std::function<void()>(), nullptr, nullptr);
- SIMIX_context_set_current(context);
-
- XBT_CDEBUG(xbt_parmap, "New worker thread created");
-
- /* Worker's main loop */
- while (1) {
- round++;
- parmap.synchro->worker_wait(round);
- if (parmap.status == PARMAP_DESTROY)
- break;
-
- XBT_CDEBUG(xbt_parmap, "Worker %d got a job", data->worker_id);
- parmap.work();
- parmap.synchro->worker_signal();
- XBT_CDEBUG(xbt_parmap, "Worker %d has finished", data->worker_id);
- }
- /* We are destroying the parmap */
- delete context;
- delete data;
- return nullptr;
-}
-
-template <typename T> Parmap<T>::PosixSynchro::PosixSynchro(Parmap<T>& parmap) : Synchro(parmap)
-{
- ready_cond = xbt_os_cond_init();
- ready_mutex = xbt_os_mutex_init();
- done_cond = xbt_os_cond_init();
- done_mutex = xbt_os_mutex_init();
-}
-
-template <typename T> Parmap<T>::PosixSynchro::~PosixSynchro()
-{
- xbt_os_cond_destroy(ready_cond);
- xbt_os_mutex_destroy(ready_mutex);
- xbt_os_cond_destroy(done_cond);
- xbt_os_mutex_destroy(done_mutex);
-}
-
-template <typename T> void Parmap<T>::PosixSynchro::master_signal()
-{
- xbt_os_mutex_acquire(ready_mutex);
- this->parmap.thread_counter = 1;
- this->parmap.work_round++;
- /* wake all workers */
- xbt_os_cond_broadcast(ready_cond);
- xbt_os_mutex_release(ready_mutex);
-}
-
-template <typename T> void Parmap<T>::PosixSynchro::master_wait()
-{
- xbt_os_mutex_acquire(done_mutex);
- while (this->parmap.thread_counter < this->parmap.num_workers) {
- /* wait for all workers to be ready */
- xbt_os_cond_wait(done_cond, done_mutex);
- }
- xbt_os_mutex_release(done_mutex);
-}
-
-template <typename T> void Parmap<T>::PosixSynchro::worker_signal()
-{
- xbt_os_mutex_acquire(done_mutex);
- this->parmap.thread_counter++;
- if (this->parmap.thread_counter == this->parmap.num_workers) {
- /* all workers have finished, wake the controller */
- xbt_os_cond_signal(done_cond);
- }
- xbt_os_mutex_release(done_mutex);
-}
-
-template <typename T> void Parmap<T>::PosixSynchro::worker_wait(unsigned round)
-{
- xbt_os_mutex_acquire(ready_mutex);
- /* wait for more work */
- while (this->parmap.work_round != round) {
- xbt_os_cond_wait(ready_cond, ready_mutex);
- }
- xbt_os_mutex_release(ready_mutex);
-}
-
-#if HAVE_FUTEX_H
-template <typename T> inline void Parmap<T>::FutexSynchro::futex_wait(unsigned* uaddr, unsigned val)
-{
- XBT_CVERB(xbt_parmap, "Waiting on futex %p", uaddr);
- syscall(SYS_futex, uaddr, FUTEX_WAIT_PRIVATE, val, nullptr, nullptr, 0);
-}
-
-template <typename T> inline void Parmap<T>::FutexSynchro::futex_wake(unsigned* uaddr, unsigned val)
-{
- XBT_CVERB(xbt_parmap, "Waking futex %p", uaddr);
- syscall(SYS_futex, uaddr, FUTEX_WAKE_PRIVATE, val, nullptr, nullptr, 0);
-}
-
-template <typename T> void Parmap<T>::FutexSynchro::master_signal()
-{
- __atomic_store_n(&this->parmap.thread_counter, 1, __ATOMIC_SEQ_CST);
- __atomic_add_fetch(&this->parmap.work_round, 1, __ATOMIC_SEQ_CST);
- /* wake all workers */
- futex_wake(&this->parmap.work_round, std::numeric_limits<int>::max());
-}
-
-template <typename T> void Parmap<T>::FutexSynchro::master_wait()
-{
- unsigned count = __atomic_load_n(&this->parmap.thread_counter, __ATOMIC_SEQ_CST);
- while (count < this->parmap.num_workers) {
- /* wait for all workers to be ready */
- futex_wait(&this->parmap.thread_counter, count);
- count = __atomic_load_n(&this->parmap.thread_counter, __ATOMIC_SEQ_CST);
- }
-}
-
-template <typename T> void Parmap<T>::FutexSynchro::worker_signal()
-{
- unsigned count = __atomic_add_fetch(&this->parmap.thread_counter, 1, __ATOMIC_SEQ_CST);
- if (count == this->parmap.num_workers) {
- /* all workers have finished, wake the controller */
- futex_wake(&this->parmap.thread_counter, std::numeric_limits<int>::max());
- }
-}
-
-template <typename T> void Parmap<T>::FutexSynchro::worker_wait(unsigned round)
-{
- unsigned work_round = __atomic_load_n(&this->parmap.work_round, __ATOMIC_SEQ_CST);
- /* wait for more work */
- while (work_round != round) {
- futex_wait(&this->parmap.work_round, work_round);
- work_round = __atomic_load_n(&this->parmap.work_round, __ATOMIC_SEQ_CST);
- }
-}
-#endif
-
-template <typename T> void Parmap<T>::BusyWaitSynchro::master_signal()
-{
- __atomic_store_n(&this->parmap.thread_counter, 1, __ATOMIC_SEQ_CST);
- __atomic_add_fetch(&this->parmap.work_round, 1, __ATOMIC_SEQ_CST);
-}
-
-template <typename T> void Parmap<T>::BusyWaitSynchro::master_wait()
-{
- while (__atomic_load_n(&this->parmap.thread_counter, __ATOMIC_SEQ_CST) < this->parmap.num_workers) {
- xbt_os_thread_yield();
- }
-}
-
-template <typename T> void Parmap<T>::BusyWaitSynchro::worker_signal()
-{
- __atomic_add_fetch(&this->parmap.thread_counter, 1, __ATOMIC_SEQ_CST);
-}
-
-template <typename T> void Parmap<T>::BusyWaitSynchro::worker_wait(unsigned round)
-{
- /* wait for more work */
- while (__atomic_load_n(&this->parmap.work_round, __ATOMIC_SEQ_CST) != round) {
- xbt_os_thread_yield();
- }
-}
-
-/** \} */
-}
-}
-
-#endif
