1 /* Copyright (c) 2004-2017. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
8 #include "src/internal_config.h"
14 #include <sys/syscall.h>
18 #include <linux/futex.h>
22 #include "xbt/parmap.h"
24 #include "xbt/function_types.h"
25 #include "xbt/dynar.h"
26 #include "xbt/xbt_os_thread.h"
27 #include "xbt/sysdep.h"
28 #include "src/simix/smx_private.h"
30 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_parmap, xbt, "parmap: parallel map");
35 } e_xbt_parmap_flag_t;
37 static void xbt_parmap_set_mode(xbt_parmap_t parmap, e_xbt_parmap_mode_t mode);
38 static void *xbt_parmap_worker_main(void *parmap);
39 static void xbt_parmap_work(xbt_parmap_t parmap);
41 static void xbt_parmap_posix_master_wait(xbt_parmap_t parmap);
42 static void xbt_parmap_posix_worker_signal(xbt_parmap_t parmap);
43 static void xbt_parmap_posix_master_signal(xbt_parmap_t parmap);
44 static void xbt_parmap_posix_worker_wait(xbt_parmap_t parmap, unsigned round);
47 static void xbt_parmap_futex_master_wait(xbt_parmap_t parmap);
48 static void xbt_parmap_futex_worker_signal(xbt_parmap_t parmap);
49 static void xbt_parmap_futex_master_signal(xbt_parmap_t parmap);
50 static void xbt_parmap_futex_worker_wait(xbt_parmap_t parmap, unsigned round);
51 static void futex_wait(unsigned *uaddr, unsigned val);
52 static void futex_wake(unsigned *uaddr, unsigned val);
55 static void xbt_parmap_busy_master_wait(xbt_parmap_t parmap);
56 static void xbt_parmap_busy_worker_signal(xbt_parmap_t parmap);
57 static void xbt_parmap_busy_master_signal(xbt_parmap_t parmap);
58 static void xbt_parmap_busy_worker_wait(xbt_parmap_t parmap, unsigned round);
61 * \brief Parallel map structure
63 typedef struct s_xbt_parmap {
64 e_xbt_parmap_flag_t status; /**< is the parmap active or being destroyed? */
65 unsigned work; /**< index of the current round */
66 unsigned thread_counter; /**< number of workers that have done the work */
68 unsigned int num_workers; /**< total number of worker threads including the controller */
69 xbt_os_thread_t *workers; /**< worker thread handlers */
70 void_f_pvoid_t fun; /**< function to run in parallel on each element of data */
71 xbt_dynar_t data; /**< parameters to pass to fun in parallel */
72 std::atomic<unsigned int> index; /**< index of the next element of data to pick */
75 xbt_os_cond_t ready_cond;
76 xbt_os_mutex_t ready_mutex;
77 xbt_os_cond_t done_cond;
78 xbt_os_mutex_t done_mutex;
80 /* fields that depend on the synchronization mode */
81 e_xbt_parmap_mode_t mode; /**< synchronization mode */
82 void (*master_wait_f)(xbt_parmap_t); /**< wait for the workers to have done the work */
83 void (*worker_signal_f)(xbt_parmap_t); /**< signal the master that a worker has done the work */
84 void (*master_signal_f)(xbt_parmap_t); /**< wakes the workers threads to process tasks */
85 void (*worker_wait_f)(xbt_parmap_t, unsigned); /**< waits for more work */
89 * \brief Thread data transmission structure
91 typedef struct s_xbt_parmap_thread_data{
94 } s_xbt_parmap_thread_data_t;
96 typedef s_xbt_parmap_thread_data_t *xbt_parmap_thread_data_t;
99 * \brief Creates a parallel map object
100 * \param num_workers number of worker threads to create
101 * \param mode how to synchronize the worker threads
102 * \return the parmap created
104 xbt_parmap_t xbt_parmap_new(unsigned int num_workers, e_xbt_parmap_mode_t mode)
106 XBT_DEBUG("Create new parmap (%u workers)", num_workers);
108 /* Initialize the thread pool data structure */
109 xbt_parmap_t parmap = new s_xbt_parmap_t();
110 parmap->workers = xbt_new(xbt_os_thread_t, num_workers);
112 parmap->num_workers = num_workers;
113 parmap->status = XBT_PARMAP_WORK;
114 xbt_parmap_set_mode(parmap, mode);
116 /* Create the pool of worker threads */
117 xbt_parmap_thread_data_t data;
118 parmap->workers[0] = nullptr;
119 #if HAVE_PTHREAD_SETAFFINITY
122 for (unsigned int i = 1; i < num_workers; i++) {
123 data = xbt_new0(s_xbt_parmap_thread_data_t, 1);
124 data->parmap = parmap;
126 parmap->workers[i] = xbt_os_thread_create(nullptr, xbt_parmap_worker_main, data, nullptr);
127 #if HAVE_PTHREAD_SETAFFINITY
128 xbt_os_thread_bind(parmap->workers[i], core_bind);
129 if (core_bind != xbt_os_get_numcores() - 1)
139 * \brief Destroys a parmap
140 * \param parmap the parmap to destroy
142 void xbt_parmap_destroy(xbt_parmap_t parmap)
148 parmap->status = XBT_PARMAP_DESTROY;
149 parmap->master_signal_f(parmap);
152 for (i = 1; i < parmap->num_workers; i++)
153 xbt_os_thread_join(parmap->workers[i], nullptr);
155 xbt_os_cond_destroy(parmap->ready_cond);
156 xbt_os_mutex_destroy(parmap->ready_mutex);
157 xbt_os_cond_destroy(parmap->done_cond);
158 xbt_os_mutex_destroy(parmap->done_mutex);
160 xbt_free(parmap->workers);
165 * \brief Sets the synchronization mode of a parmap.
166 * \param parmap a parallel map object
167 * \param mode the synchronization mode
169 static void xbt_parmap_set_mode(xbt_parmap_t parmap, e_xbt_parmap_mode_t mode)
171 if (mode == XBT_PARMAP_DEFAULT) {
173 mode = XBT_PARMAP_FUTEX;
175 mode = XBT_PARMAP_POSIX;
181 case XBT_PARMAP_POSIX:
182 parmap->master_wait_f = &xbt_parmap_posix_master_wait;
183 parmap->worker_signal_f = &xbt_parmap_posix_worker_signal;
184 parmap->master_signal_f = &xbt_parmap_posix_master_signal;
185 parmap->worker_wait_f = &xbt_parmap_posix_worker_wait;
187 parmap->ready_cond = xbt_os_cond_init();
188 parmap->ready_mutex = xbt_os_mutex_init();
189 parmap->done_cond = xbt_os_cond_init();
190 parmap->done_mutex = xbt_os_mutex_init();
192 case XBT_PARMAP_FUTEX:
194 parmap->master_wait_f = &xbt_parmap_futex_master_wait;
195 parmap->worker_signal_f = &xbt_parmap_futex_worker_signal;
196 parmap->master_signal_f = &xbt_parmap_futex_master_signal;
197 parmap->worker_wait_f = &xbt_parmap_futex_worker_wait;
199 xbt_os_cond_destroy(parmap->ready_cond);
200 xbt_os_mutex_destroy(parmap->ready_mutex);
201 xbt_os_cond_destroy(parmap->done_cond);
202 xbt_os_mutex_destroy(parmap->done_mutex);
205 xbt_die("Futex is not available on this OS.");
207 case XBT_PARMAP_BUSY_WAIT:
208 parmap->master_wait_f = &xbt_parmap_busy_master_wait;
209 parmap->worker_signal_f = &xbt_parmap_busy_worker_signal;
210 parmap->master_signal_f = &xbt_parmap_busy_master_signal;
211 parmap->worker_wait_f = &xbt_parmap_busy_worker_wait;
213 xbt_os_cond_destroy(parmap->ready_cond);
214 xbt_os_mutex_destroy(parmap->ready_mutex);
215 xbt_os_cond_destroy(parmap->done_cond);
216 xbt_os_mutex_destroy(parmap->done_mutex);
218 case XBT_PARMAP_DEFAULT:
225 * \brief Applies a list of tasks in parallel.
226 * \param parmap a parallel map object
227 * \param fun the function to call in parallel
228 * \param data each element of this dynar will be passed as an argument to fun
230 void xbt_parmap_apply(xbt_parmap_t parmap, void_f_pvoid_t fun, xbt_dynar_t data)
232 /* Assign resources to worker threads (we are maestro here)*/
236 parmap->master_signal_f(parmap); // maestro runs futex_wait to wake all the minions (the working threads)
237 xbt_parmap_work(parmap); // maestro works with its minions
238 parmap->master_wait_f(parmap); // When there is no more work to do, then maestro waits for the last minion to stop
239 XBT_DEBUG("Job done"); // ... and proceeds
243 * \brief Returns a next task to process.
245 * Worker threads call this function to get more work.
247 * \return the next task to process, or nullptr if there is no more work
249 void* xbt_parmap_next(xbt_parmap_t parmap)
251 unsigned int index = parmap->index++;
252 if (index < xbt_dynar_length(parmap->data)) {
253 return xbt_dynar_get_as(parmap->data, index, void*);
258 static void xbt_parmap_work(xbt_parmap_t parmap)
260 unsigned int index = parmap->index++;
261 while (index < xbt_dynar_length(parmap->data)){
262 parmap->fun(xbt_dynar_get_as(parmap->data, index, void*));
263 index = parmap->index++;
268 * \brief Main function of a worker thread.
269 * \param arg the parmap
271 static void *xbt_parmap_worker_main(void *arg)
273 xbt_parmap_thread_data_t data = static_cast<xbt_parmap_thread_data_t>(arg);
274 xbt_parmap_t parmap = data->parmap;
276 smx_context_t context = SIMIX_context_new(std::function<void()>(), nullptr, nullptr);
277 SIMIX_context_set_current(context);
279 XBT_DEBUG("New worker thread created");
281 /* Worker's main loop */
284 parmap->worker_wait_f(parmap, round);
285 if (parmap->status == XBT_PARMAP_WORK) {
286 XBT_DEBUG("Worker %d got a job", data->worker_id);
288 xbt_parmap_work(parmap);
289 parmap->worker_signal_f(parmap);
291 XBT_DEBUG("Worker %d has finished", data->worker_id);
292 /* We are destroying the parmap */
302 static void futex_wait(unsigned *uaddr, unsigned val)
304 XBT_VERB("Waiting on futex %p", uaddr);
305 syscall(SYS_futex, uaddr, FUTEX_WAIT_PRIVATE, val, nullptr, nullptr, 0);
308 static void futex_wake(unsigned *uaddr, unsigned val)
310 XBT_VERB("Waking futex %p", uaddr);
311 syscall(SYS_futex, uaddr, FUTEX_WAKE_PRIVATE, val, nullptr, nullptr, 0);
316 * \brief Starts the parmap: waits for all workers to be ready and returns.
318 * This function is called by the controller thread.
320 * \param parmap a parmap
322 static void xbt_parmap_posix_master_wait(xbt_parmap_t parmap)
324 xbt_os_mutex_acquire(parmap->done_mutex);
325 if (parmap->thread_counter < parmap->num_workers) {
326 /* wait for all workers to be ready */
327 xbt_os_cond_wait(parmap->done_cond, parmap->done_mutex);
329 xbt_os_mutex_release(parmap->done_mutex);
333 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
335 * This function is called by all worker threads when they end (not including the controller).
337 * \param parmap a parmap
339 static void xbt_parmap_posix_worker_signal(xbt_parmap_t parmap)
341 xbt_os_mutex_acquire(parmap->done_mutex);
342 parmap->thread_counter++;
343 if (parmap->thread_counter == parmap->num_workers) {
344 /* all workers have finished, wake the controller */
345 xbt_os_cond_signal(parmap->done_cond);
347 xbt_os_mutex_release(parmap->done_mutex);
351 * \brief Wakes all workers and waits for them to finish the tasks.
353 * This function is called by the controller thread.
355 * \param parmap a parmap
357 static void xbt_parmap_posix_master_signal(xbt_parmap_t parmap)
359 xbt_os_mutex_acquire(parmap->ready_mutex);
360 parmap->thread_counter = 1;
362 /* wake all workers */
363 xbt_os_cond_broadcast(parmap->ready_cond);
364 xbt_os_mutex_release(parmap->ready_mutex);
368 * \brief Waits for some work to process.
370 * This function is called by each worker thread (not including the controller) when it has no more work to do.
372 * \param parmap a parmap
373 * \param round the expected round number
375 static void xbt_parmap_posix_worker_wait(xbt_parmap_t parmap, unsigned round)
377 xbt_os_mutex_acquire(parmap->ready_mutex);
378 /* wait for more work */
379 if (parmap->work != round) {
380 xbt_os_cond_wait(parmap->ready_cond, parmap->ready_mutex);
382 xbt_os_mutex_release(parmap->ready_mutex);
387 * \brief Starts the parmap: waits for all workers to be ready and returns.
389 * This function is called by the controller thread.
391 * \param parmap a parmap
393 static void xbt_parmap_futex_master_wait(xbt_parmap_t parmap)
395 unsigned count = parmap->thread_counter;
396 while (count < parmap->num_workers) {
397 /* wait for all workers to be ready */
398 futex_wait(&parmap->thread_counter, count);
399 count = parmap->thread_counter;
404 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
406 * This function is called by all worker threads when they end (not including the controller).
408 * \param parmap a parmap
410 static void xbt_parmap_futex_worker_signal(xbt_parmap_t parmap)
412 unsigned count = __sync_add_and_fetch(&parmap->thread_counter, 1);
413 if (count == parmap->num_workers) {
414 /* all workers have finished, wake the controller */
415 futex_wake(&parmap->thread_counter, INT_MAX);
420 * \brief Wakes all workers and waits for them to finish the tasks.
422 * This function is called by the controller thread.
424 * \param parmap a parmap
426 static void xbt_parmap_futex_master_signal(xbt_parmap_t parmap)
428 parmap->thread_counter = 1;
429 __sync_add_and_fetch(&parmap->work, 1);
430 /* wake all workers */
431 futex_wake(&parmap->work, INT_MAX);
435 * \brief Waits for some work to process.
437 * This function is called by each worker thread (not including the controller) when it has no more work to do.
439 * \param parmap a parmap
440 * \param round the expected round number
442 static void xbt_parmap_futex_worker_wait(xbt_parmap_t parmap, unsigned round)
444 unsigned work = parmap->work;
445 /* wait for more work */
446 while (work != round) {
447 futex_wait(&parmap->work, work);
454 * \brief Starts the parmap: waits for all workers to be ready and returns.
456 * This function is called by the controller thread.
458 * \param parmap a parmap
460 static void xbt_parmap_busy_master_wait(xbt_parmap_t parmap)
462 while (parmap->thread_counter < parmap->num_workers) {
463 xbt_os_thread_yield();
468 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
470 * This function is called by all worker threads when they end.
472 * \param parmap a parmap
474 static void xbt_parmap_busy_worker_signal(xbt_parmap_t parmap)
476 __sync_add_and_fetch(&parmap->thread_counter, 1);
480 * \brief Wakes all workers and waits for them to finish the tasks.
482 * This function is called by the controller thread.
484 * \param parmap a parmap
486 static void xbt_parmap_busy_master_signal(xbt_parmap_t parmap)
488 parmap->thread_counter = 1;
489 __sync_add_and_fetch(&parmap->work, 1);
493 * \brief Waits for some work to process.
495 * This function is called by each worker thread (not including the controller) when it has no more work to do.
497 * \param parmap a parmap
498 * \param round the expected round number
500 static void xbt_parmap_busy_worker_wait(xbt_parmap_t parmap, unsigned round)
502 /* wait for more work */
503 while (parmap->work != round) {
504 xbt_os_thread_yield();