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. */
9 #include "src/internal_config.h"
15 #include <sys/syscall.h>
20 #include <linux/futex.h>
23 #include "xbt/parmap.h"
25 #include "xbt/function_types.h"
26 #include "xbt/dynar.h"
27 #include "xbt/xbt_os_thread.h"
28 #include "xbt/sysdep.h"
29 #include "src/simix/smx_private.h"
31 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_parmap, xbt, "parmap: parallel map");
36 } e_xbt_parmap_flag_t;
38 static void xbt_parmap_set_mode(xbt_parmap_t parmap, e_xbt_parmap_mode_t mode);
39 static void *xbt_parmap_worker_main(void *parmap);
40 static void xbt_parmap_work(xbt_parmap_t parmap);
42 static void xbt_parmap_posix_master_wait(xbt_parmap_t parmap);
43 static void xbt_parmap_posix_worker_signal(xbt_parmap_t parmap);
44 static void xbt_parmap_posix_master_signal(xbt_parmap_t parmap);
45 static void xbt_parmap_posix_worker_wait(xbt_parmap_t parmap, unsigned round);
48 static void xbt_parmap_futex_master_wait(xbt_parmap_t parmap);
49 static void xbt_parmap_futex_worker_signal(xbt_parmap_t parmap);
50 static void xbt_parmap_futex_master_signal(xbt_parmap_t parmap);
51 static void xbt_parmap_futex_worker_wait(xbt_parmap_t parmap, unsigned round);
52 static void futex_wait(unsigned *uaddr, unsigned val);
53 static void futex_wake(unsigned *uaddr, unsigned val);
56 static void xbt_parmap_busy_master_wait(xbt_parmap_t parmap);
57 static void xbt_parmap_busy_worker_signal(xbt_parmap_t parmap);
58 static void xbt_parmap_busy_master_signal(xbt_parmap_t parmap);
59 static void xbt_parmap_busy_worker_wait(xbt_parmap_t parmap, unsigned round);
62 * \brief Parallel map structure
64 typedef struct s_xbt_parmap {
65 e_xbt_parmap_flag_t status; /**< is the parmap active or being destroyed? */
66 unsigned work; /**< index of the current round */
67 unsigned thread_counter; /**< number of workers that have done the work */
69 unsigned int num_workers; /**< total number of worker threads including the controller */
70 xbt_os_thread_t *workers; /**< worker thread handlers */
71 void_f_pvoid_t fun; /**< function to run in parallel on each element of data */
72 xbt_dynar_t data; /**< parameters to pass to fun in parallel */
73 std::atomic<unsigned int> index; /**< index of the next element of data to pick */
76 xbt_os_cond_t ready_cond;
77 xbt_os_mutex_t ready_mutex;
78 xbt_os_cond_t done_cond;
79 xbt_os_mutex_t done_mutex;
81 /* fields that depend on the synchronization mode */
82 e_xbt_parmap_mode_t mode; /**< synchronization mode */
83 void (*master_wait_f)(xbt_parmap_t); /**< wait for the workers to have done the work */
84 void (*worker_signal_f)(xbt_parmap_t); /**< signal the master that a worker has done the work */
85 void (*master_signal_f)(xbt_parmap_t); /**< wakes the workers threads to process tasks */
86 void (*worker_wait_f)(xbt_parmap_t, unsigned); /**< waits for more work */
90 * \brief Thread data transmission structure
92 typedef struct s_xbt_parmap_thread_data{
95 } s_xbt_parmap_thread_data_t;
97 typedef s_xbt_parmap_thread_data_t *xbt_parmap_thread_data_t;
100 * \brief Creates a parallel map object
101 * \param num_workers number of worker threads to create
102 * \param mode how to synchronize the worker threads
103 * \return the parmap created
105 xbt_parmap_t xbt_parmap_new(unsigned int num_workers, e_xbt_parmap_mode_t mode)
107 XBT_DEBUG("Create new parmap (%u workers)", num_workers);
109 /* Initialize the thread pool data structure */
110 xbt_parmap_t parmap = new s_xbt_parmap_t();
111 parmap->workers = xbt_new(xbt_os_thread_t, num_workers);
113 parmap->num_workers = num_workers;
114 parmap->status = XBT_PARMAP_WORK;
115 xbt_parmap_set_mode(parmap, mode);
117 /* Create the pool of worker threads */
118 parmap->workers[0] = nullptr;
119 #if HAVE_PTHREAD_SETAFFINITY
122 for (unsigned int i = 1; i < num_workers; i++) {
123 xbt_parmap_thread_data_t 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:
227 * \brief Applies a list of tasks in parallel.
228 * \param parmap a parallel map object
229 * \param fun the function to call in parallel
230 * \param data each element of this dynar will be passed as an argument to fun
232 void xbt_parmap_apply(xbt_parmap_t parmap, void_f_pvoid_t fun, xbt_dynar_t data)
234 /* Assign resources to worker threads (we are maestro here)*/
238 parmap->master_signal_f(parmap); // maestro runs futex_wait to wake all the minions (the working threads)
239 xbt_parmap_work(parmap); // maestro works with its minions
240 parmap->master_wait_f(parmap); // When there is no more work to do, then maestro waits for the last minion to stop
241 XBT_DEBUG("Job done"); // ... and proceeds
245 * \brief Returns a next task to process.
247 * Worker threads call this function to get more work.
249 * \return the next task to process, or nullptr if there is no more work
251 void* xbt_parmap_next(xbt_parmap_t parmap)
253 unsigned int index = parmap->index++;
254 if (index < xbt_dynar_length(parmap->data)) {
255 return xbt_dynar_get_as(parmap->data, index, void*);
260 static void xbt_parmap_work(xbt_parmap_t parmap)
262 unsigned int index = parmap->index++;
263 while (index < xbt_dynar_length(parmap->data)){
264 parmap->fun(xbt_dynar_get_as(parmap->data, index, void*));
265 index = parmap->index++;
270 * \brief Main function of a worker thread.
271 * \param arg the parmap
273 static void *xbt_parmap_worker_main(void *arg)
275 xbt_parmap_thread_data_t data = static_cast<xbt_parmap_thread_data_t>(arg);
276 xbt_parmap_t parmap = data->parmap;
278 smx_context_t context = SIMIX_context_new(std::function<void()>(), nullptr, nullptr);
279 SIMIX_context_set_current(context);
281 XBT_DEBUG("New worker thread created");
283 /* Worker's main loop */
286 parmap->worker_wait_f(parmap, round);
287 if (parmap->status == XBT_PARMAP_WORK) {
288 XBT_DEBUG("Worker %d got a job", data->worker_id);
290 xbt_parmap_work(parmap);
291 parmap->worker_signal_f(parmap);
293 XBT_DEBUG("Worker %d has finished", data->worker_id);
294 /* We are destroying the parmap */
304 static void futex_wait(unsigned *uaddr, unsigned val)
306 XBT_VERB("Waiting on futex %p", uaddr);
307 syscall(SYS_futex, uaddr, FUTEX_WAIT_PRIVATE, val, nullptr, nullptr, 0);
310 static void futex_wake(unsigned *uaddr, unsigned val)
312 XBT_VERB("Waking futex %p", uaddr);
313 syscall(SYS_futex, uaddr, FUTEX_WAKE_PRIVATE, val, nullptr, nullptr, 0);
318 * \brief Starts the parmap: waits for all workers to be ready and returns.
320 * This function is called by the controller thread.
322 * \param parmap a parmap
324 static void xbt_parmap_posix_master_wait(xbt_parmap_t parmap)
326 xbt_os_mutex_acquire(parmap->done_mutex);
327 if (parmap->thread_counter < parmap->num_workers) {
328 /* wait for all workers to be ready */
329 xbt_os_cond_wait(parmap->done_cond, parmap->done_mutex);
331 xbt_os_mutex_release(parmap->done_mutex);
335 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
337 * This function is called by all worker threads when they end (not including the controller).
339 * \param parmap a parmap
341 static void xbt_parmap_posix_worker_signal(xbt_parmap_t parmap)
343 xbt_os_mutex_acquire(parmap->done_mutex);
344 parmap->thread_counter++;
345 if (parmap->thread_counter == parmap->num_workers) {
346 /* all workers have finished, wake the controller */
347 xbt_os_cond_signal(parmap->done_cond);
349 xbt_os_mutex_release(parmap->done_mutex);
353 * \brief Wakes all workers and waits for them to finish the tasks.
355 * This function is called by the controller thread.
357 * \param parmap a parmap
359 static void xbt_parmap_posix_master_signal(xbt_parmap_t parmap)
361 xbt_os_mutex_acquire(parmap->ready_mutex);
362 parmap->thread_counter = 1;
364 /* wake all workers */
365 xbt_os_cond_broadcast(parmap->ready_cond);
366 xbt_os_mutex_release(parmap->ready_mutex);
370 * \brief Waits for some work to process.
372 * This function is called by each worker thread (not including the controller) when it has no more work to do.
374 * \param parmap a parmap
375 * \param round the expected round number
377 static void xbt_parmap_posix_worker_wait(xbt_parmap_t parmap, unsigned round)
379 xbt_os_mutex_acquire(parmap->ready_mutex);
380 /* wait for more work */
381 if (parmap->work != round) {
382 xbt_os_cond_wait(parmap->ready_cond, parmap->ready_mutex);
384 xbt_os_mutex_release(parmap->ready_mutex);
389 * \brief Starts the parmap: waits for all workers to be ready and returns.
391 * This function is called by the controller thread.
393 * \param parmap a parmap
395 static void xbt_parmap_futex_master_wait(xbt_parmap_t parmap)
397 unsigned count = parmap->thread_counter;
398 while (count < parmap->num_workers) {
399 /* wait for all workers to be ready */
400 futex_wait(&parmap->thread_counter, count);
401 count = parmap->thread_counter;
406 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
408 * This function is called by all worker threads when they end (not including the controller).
410 * \param parmap a parmap
412 static void xbt_parmap_futex_worker_signal(xbt_parmap_t parmap)
414 unsigned count = __sync_add_and_fetch(&parmap->thread_counter, 1);
415 if (count == parmap->num_workers) {
416 /* all workers have finished, wake the controller */
417 futex_wake(&parmap->thread_counter, INT_MAX);
422 * \brief Wakes all workers and waits for them to finish the tasks.
424 * This function is called by the controller thread.
426 * \param parmap a parmap
428 static void xbt_parmap_futex_master_signal(xbt_parmap_t parmap)
430 parmap->thread_counter = 1;
431 __sync_add_and_fetch(&parmap->work, 1);
432 /* wake all workers */
433 futex_wake(&parmap->work, INT_MAX);
437 * \brief Waits for some work to process.
439 * This function is called by each worker thread (not including the controller) when it has no more work to do.
441 * \param parmap a parmap
442 * \param round the expected round number
444 static void xbt_parmap_futex_worker_wait(xbt_parmap_t parmap, unsigned round)
446 unsigned work = parmap->work;
447 /* wait for more work */
448 while (work != round) {
449 futex_wait(&parmap->work, work);
456 * \brief Starts the parmap: waits for all workers to be ready and returns.
458 * This function is called by the controller thread.
460 * \param parmap a parmap
462 static void xbt_parmap_busy_master_wait(xbt_parmap_t parmap)
464 while (parmap->thread_counter < parmap->num_workers) {
465 xbt_os_thread_yield();
470 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
472 * This function is called by all worker threads when they end.
474 * \param parmap a parmap
476 static void xbt_parmap_busy_worker_signal(xbt_parmap_t parmap)
478 __sync_add_and_fetch(&parmap->thread_counter, 1);
482 * \brief Wakes all workers and waits for them to finish the tasks.
484 * This function is called by the controller thread.
486 * \param parmap a parmap
488 static void xbt_parmap_busy_master_signal(xbt_parmap_t parmap)
490 parmap->thread_counter = 1;
491 __sync_add_and_fetch(&parmap->work, 1);
495 * \brief Waits for some work to process.
497 * This function is called by each worker thread (not including the controller) when it has no more work to do.
499 * \param parmap a parmap
500 * \param round the expected round number
502 static void xbt_parmap_busy_worker_wait(xbt_parmap_t parmap, unsigned round)
504 /* wait for more work */
505 while (parmap->work != round) {
506 xbt_os_thread_yield();