1 /* Copyright (c) 2004-2005, 2007, 2009-2014. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
9 #include "src/internal_config.h"
15 #include <sys/syscall.h>
19 #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 xbt_parmap_thread_data_t data;
119 parmap->workers[0] = nullptr;
120 #if HAVE_PTHREAD_SETAFFINITY
123 for (unsigned int i = 1; i < num_workers; i++) {
124 data = xbt_new0(s_xbt_parmap_thread_data_t, 1);
125 data->parmap = parmap;
127 parmap->workers[i] = xbt_os_thread_create(nullptr, xbt_parmap_worker_main, data, nullptr);
128 #if HAVE_PTHREAD_SETAFFINITY
129 xbt_os_thread_bind(parmap->workers[i], core_bind);
130 if (core_bind != xbt_os_get_numcores() - 1)
140 * \brief Destroys a parmap
141 * \param parmap the parmap to destroy
143 void xbt_parmap_destroy(xbt_parmap_t parmap)
149 parmap->status = XBT_PARMAP_DESTROY;
150 parmap->master_signal_f(parmap);
153 for (i = 1; i < parmap->num_workers; i++)
154 xbt_os_thread_join(parmap->workers[i], nullptr);
156 xbt_os_cond_destroy(parmap->ready_cond);
157 xbt_os_mutex_destroy(parmap->ready_mutex);
158 xbt_os_cond_destroy(parmap->done_cond);
159 xbt_os_mutex_destroy(parmap->done_mutex);
161 xbt_free(parmap->workers);
166 * \brief Sets the synchronization mode of a parmap.
167 * \param parmap a parallel map object
168 * \param mode the synchronization mode
170 static void xbt_parmap_set_mode(xbt_parmap_t parmap, e_xbt_parmap_mode_t mode)
172 if (mode == XBT_PARMAP_DEFAULT) {
174 mode = XBT_PARMAP_FUTEX;
176 mode = XBT_PARMAP_POSIX;
182 case XBT_PARMAP_POSIX:
183 parmap->master_wait_f = xbt_parmap_posix_master_wait;
184 parmap->worker_signal_f = xbt_parmap_posix_worker_signal;
185 parmap->master_signal_f = xbt_parmap_posix_master_signal;
186 parmap->worker_wait_f = xbt_parmap_posix_worker_wait;
188 parmap->ready_cond = xbt_os_cond_init();
189 parmap->ready_mutex = xbt_os_mutex_init();
190 parmap->done_cond = xbt_os_cond_init();
191 parmap->done_mutex = xbt_os_mutex_init();
193 case XBT_PARMAP_FUTEX:
195 parmap->master_wait_f = xbt_parmap_futex_master_wait;
196 parmap->worker_signal_f = xbt_parmap_futex_worker_signal;
197 parmap->master_signal_f = xbt_parmap_futex_master_signal;
198 parmap->worker_wait_f = xbt_parmap_futex_worker_wait;
200 xbt_os_cond_destroy(parmap->ready_cond);
201 xbt_os_mutex_destroy(parmap->ready_mutex);
202 xbt_os_cond_destroy(parmap->done_cond);
203 xbt_os_mutex_destroy(parmap->done_mutex);
206 xbt_die("Futex is not available on this OS.");
208 case XBT_PARMAP_BUSY_WAIT:
209 parmap->master_wait_f = xbt_parmap_busy_master_wait;
210 parmap->worker_signal_f = xbt_parmap_busy_worker_signal;
211 parmap->master_signal_f = xbt_parmap_busy_master_signal;
212 parmap->worker_wait_f = xbt_parmap_busy_worker_wait;
214 xbt_os_cond_destroy(parmap->ready_cond);
215 xbt_os_mutex_destroy(parmap->ready_mutex);
216 xbt_os_cond_destroy(parmap->done_cond);
217 xbt_os_mutex_destroy(parmap->done_mutex);
219 case XBT_PARMAP_DEFAULT:
226 * \brief Applies a list of tasks in parallel.
227 * \param parmap a parallel map object
228 * \param fun the function to call in parallel
229 * \param data each element of this dynar will be passed as an argument to fun
231 void xbt_parmap_apply(xbt_parmap_t parmap, void_f_pvoid_t fun, xbt_dynar_t data)
233 /* Assign resources to worker threads (we are maestro here)*/
237 parmap->master_signal_f(parmap); // maestro runs futex_wait to wake all the minions (the working threads)
238 xbt_parmap_work(parmap); // maestro works with its minions
239 parmap->master_wait_f(parmap); // When there is no more work to do, then maestro waits for the last minion to stop
240 XBT_DEBUG("Job done"); // ... and proceeds
244 * \brief Returns a next task to process.
246 * Worker threads call this function to get more work.
248 * \return the next task to process, or nullptr if there is no more work
250 void* xbt_parmap_next(xbt_parmap_t parmap)
252 unsigned int index = parmap->index++;
253 if (index < xbt_dynar_length(parmap->data)) {
254 return xbt_dynar_get_as(parmap->data, index, void*);
259 static void xbt_parmap_work(xbt_parmap_t parmap)
261 unsigned int index = parmap->index++;
262 while (index < xbt_dynar_length(parmap->data)){
263 parmap->fun(xbt_dynar_get_as(parmap->data, index, void*));
264 index = parmap->index++;
269 * \brief Main function of a worker thread.
270 * \param arg the parmap
272 static void *xbt_parmap_worker_main(void *arg)
274 xbt_parmap_thread_data_t data = static_cast<xbt_parmap_thread_data_t>(arg);
275 xbt_parmap_t parmap = data->parmap;
277 smx_context_t context = SIMIX_context_new(std::function<void()>(), nullptr, nullptr);
278 SIMIX_context_set_current(context);
280 XBT_DEBUG("New worker thread created");
282 /* Worker's main loop */
285 parmap->worker_wait_f(parmap, round);
286 if (parmap->status == XBT_PARMAP_WORK) {
287 XBT_DEBUG("Worker %d got a job", data->worker_id);
289 xbt_parmap_work(parmap);
290 parmap->worker_signal_f(parmap);
292 XBT_DEBUG("Worker %d has finished", data->worker_id);
293 /* We are destroying the parmap */
303 static void futex_wait(unsigned *uaddr, unsigned val)
305 XBT_VERB("Waiting on futex %p", uaddr);
306 syscall(SYS_futex, uaddr, FUTEX_WAIT_PRIVATE, val, nullptr, nullptr, 0);
309 static void futex_wake(unsigned *uaddr, unsigned val)
311 XBT_VERB("Waking futex %p", uaddr);
312 syscall(SYS_futex, uaddr, FUTEX_WAKE_PRIVATE, val, nullptr, nullptr, 0);
317 * \brief Starts the parmap: waits for all workers to be ready and returns.
319 * This function is called by the controller thread.
321 * \param parmap a parmap
323 static void xbt_parmap_posix_master_wait(xbt_parmap_t parmap)
325 xbt_os_mutex_acquire(parmap->done_mutex);
326 if (parmap->thread_counter < parmap->num_workers) {
327 /* wait for all workers to be ready */
328 xbt_os_cond_wait(parmap->done_cond, parmap->done_mutex);
330 xbt_os_mutex_release(parmap->done_mutex);
334 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
336 * This function is called by all worker threads when they end (not including the controller).
338 * \param parmap a parmap
340 static void xbt_parmap_posix_worker_signal(xbt_parmap_t parmap)
342 xbt_os_mutex_acquire(parmap->done_mutex);
343 parmap->thread_counter++;
344 if (parmap->thread_counter == parmap->num_workers) {
345 /* all workers have finished, wake the controller */
346 xbt_os_cond_signal(parmap->done_cond);
348 xbt_os_mutex_release(parmap->done_mutex);
352 * \brief Wakes all workers and waits for them to finish the tasks.
354 * This function is called by the controller thread.
356 * \param parmap a parmap
358 static void xbt_parmap_posix_master_signal(xbt_parmap_t parmap)
360 xbt_os_mutex_acquire(parmap->ready_mutex);
361 parmap->thread_counter = 1;
363 /* wake all workers */
364 xbt_os_cond_broadcast(parmap->ready_cond);
365 xbt_os_mutex_release(parmap->ready_mutex);
369 * \brief Waits for some work to process.
371 * This function is called by each worker thread (not including the controller) when it has no more work to do.
373 * \param parmap a parmap
374 * \param round the expected round number
376 static void xbt_parmap_posix_worker_wait(xbt_parmap_t parmap, unsigned round)
378 xbt_os_mutex_acquire(parmap->ready_mutex);
379 /* wait for more work */
380 if (parmap->work != round) {
381 xbt_os_cond_wait(parmap->ready_cond, parmap->ready_mutex);
383 xbt_os_mutex_release(parmap->ready_mutex);
388 * \brief Starts the parmap: waits for all workers to be ready and returns.
390 * This function is called by the controller thread.
392 * \param parmap a parmap
394 static void xbt_parmap_futex_master_wait(xbt_parmap_t parmap)
396 unsigned count = parmap->thread_counter;
397 while (count < parmap->num_workers) {
398 /* wait for all workers to be ready */
399 futex_wait(&parmap->thread_counter, count);
400 count = parmap->thread_counter;
405 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
407 * This function is called by all worker threads when they end (not including the controller).
409 * \param parmap a parmap
411 static void xbt_parmap_futex_worker_signal(xbt_parmap_t parmap)
413 unsigned count = __sync_add_and_fetch(&parmap->thread_counter, 1);
414 if (count == parmap->num_workers) {
415 /* all workers have finished, wake the controller */
416 futex_wake(&parmap->thread_counter, INT_MAX);
421 * \brief Wakes all workers and waits for them to finish the tasks.
423 * This function is called by the controller thread.
425 * \param parmap a parmap
427 static void xbt_parmap_futex_master_signal(xbt_parmap_t parmap)
429 parmap->thread_counter = 1;
430 __sync_add_and_fetch(&parmap->work, 1);
431 /* wake all workers */
432 futex_wake(&parmap->work, INT_MAX);
436 * \brief Waits for some work to process.
438 * This function is called by each worker thread (not including the controller) when it has no more work to do.
440 * \param parmap a parmap
441 * \param round the expected round number
443 static void xbt_parmap_futex_worker_wait(xbt_parmap_t parmap, unsigned round)
445 unsigned work = parmap->work;
446 /* wait for more work */
447 while (work != round) {
448 futex_wait(&parmap->work, work);
455 * \brief Starts the parmap: waits for all workers to be ready and returns.
457 * This function is called by the controller thread.
459 * \param parmap a parmap
461 static void xbt_parmap_busy_master_wait(xbt_parmap_t parmap)
463 while (parmap->thread_counter < parmap->num_workers) {
464 xbt_os_thread_yield();
469 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
471 * This function is called by all worker threads when they end.
473 * \param parmap a parmap
475 static void xbt_parmap_busy_worker_signal(xbt_parmap_t parmap)
477 __sync_add_and_fetch(&parmap->thread_counter, 1);
481 * \brief Wakes all workers and waits for them to finish the tasks.
483 * This function is called by the controller thread.
485 * \param parmap a parmap
487 static void xbt_parmap_busy_master_signal(xbt_parmap_t parmap)
489 parmap->thread_counter = 1;
490 __sync_add_and_fetch(&parmap->work, 1);
494 * \brief Waits for some work to process.
496 * This function is called by each worker thread (not including the controller) when it has no more work to do.
498 * \param parmap a parmap
499 * \param round the expected round number
501 static void xbt_parmap_busy_worker_wait(xbt_parmap_t parmap, unsigned round)
503 /* wait for more work */
504 while (parmap->work != round) {
505 xbt_os_thread_yield();