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] = NULL;
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(NULL, xbt_parmap_worker_main, data, NULL);
128 #if HAVE_PTHREAD_SETAFFINITY
129 xbt_os_thread_bind(parmap->workers[i], core_bind);
130 if (core_bind != xbt_os_get_numcores())
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], NULL);
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 NULL 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)
262 while ((index = parmap->index++) < xbt_dynar_length(parmap->data))
263 parmap->fun(xbt_dynar_get_as(parmap->data, index, void*));
267 * \brief Main function of a worker thread.
268 * \param arg the parmap
270 static void *xbt_parmap_worker_main(void *arg)
272 xbt_parmap_thread_data_t data = (xbt_parmap_thread_data_t) arg;
273 xbt_parmap_t parmap = data->parmap;
275 smx_context_t context = SIMIX_context_new(std::function<void()>(), NULL, NULL);
276 SIMIX_context_set_current(context);
278 XBT_DEBUG("New worker thread created");
280 /* Worker's main loop */
282 parmap->worker_wait_f(parmap, ++round);
283 if (parmap->status == XBT_PARMAP_WORK) {
284 XBT_DEBUG("Worker %d got a job", data->worker_id);
286 xbt_parmap_work(parmap);
287 parmap->worker_signal_f(parmap);
289 XBT_DEBUG("Worker %d has finished", data->worker_id);
290 /* We are destroying the parmap */
300 static void futex_wait(unsigned *uaddr, unsigned val)
302 XBT_VERB("Waiting on futex %p", uaddr);
303 syscall(SYS_futex, uaddr, FUTEX_WAIT_PRIVATE, val, NULL, NULL, 0);
306 static void futex_wake(unsigned *uaddr, unsigned val)
308 XBT_VERB("Waking futex %p", uaddr);
309 syscall(SYS_futex, uaddr, FUTEX_WAKE_PRIVATE, val, NULL, NULL, 0);
314 * \brief Starts the parmap: waits for all workers to be ready and returns.
316 * This function is called by the controller thread.
318 * \param parmap a parmap
320 static void xbt_parmap_posix_master_wait(xbt_parmap_t parmap)
322 xbt_os_mutex_acquire(parmap->done_mutex);
323 if (parmap->thread_counter < parmap->num_workers) {
324 /* wait for all workers to be ready */
325 xbt_os_cond_wait(parmap->done_cond, parmap->done_mutex);
327 xbt_os_mutex_release(parmap->done_mutex);
331 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
333 * This function is called by all worker threads when they end (not including the controller).
335 * \param parmap a parmap
337 static void xbt_parmap_posix_worker_signal(xbt_parmap_t parmap)
339 xbt_os_mutex_acquire(parmap->done_mutex);
340 if (++parmap->thread_counter == parmap->num_workers) {
341 /* all workers have finished, wake the controller */
342 xbt_os_cond_signal(parmap->done_cond);
344 xbt_os_mutex_release(parmap->done_mutex);
348 * \brief Wakes all workers and waits for them to finish the tasks.
350 * This function is called by the controller thread.
352 * \param parmap a parmap
354 static void xbt_parmap_posix_master_signal(xbt_parmap_t parmap)
356 xbt_os_mutex_acquire(parmap->ready_mutex);
357 parmap->thread_counter = 1;
359 /* wake all workers */
360 xbt_os_cond_broadcast(parmap->ready_cond);
361 xbt_os_mutex_release(parmap->ready_mutex);
365 * \brief Waits for some work to process.
367 * This function is called by each worker thread (not including the controller) when it has no more work to do.
369 * \param parmap a parmap
370 * \param round the expected round number
372 static void xbt_parmap_posix_worker_wait(xbt_parmap_t parmap, unsigned round)
374 xbt_os_mutex_acquire(parmap->ready_mutex);
375 /* wait for more work */
376 if (parmap->work != round) {
377 xbt_os_cond_wait(parmap->ready_cond, parmap->ready_mutex);
379 xbt_os_mutex_release(parmap->ready_mutex);
384 * \brief Starts the parmap: waits for all workers to be ready and returns.
386 * This function is called by the controller thread.
388 * \param parmap a parmap
390 static void xbt_parmap_futex_master_wait(xbt_parmap_t parmap)
392 unsigned count = parmap->thread_counter;
393 while (count < parmap->num_workers) {
394 /* wait for all workers to be ready */
395 futex_wait(&parmap->thread_counter, count);
396 count = parmap->thread_counter;
401 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
403 * This function is called by all worker threads when they end (not including the controller).
405 * \param parmap a parmap
407 static void xbt_parmap_futex_worker_signal(xbt_parmap_t parmap)
409 unsigned count = __sync_add_and_fetch(&parmap->thread_counter, 1);
410 if (count == parmap->num_workers) {
411 /* all workers have finished, wake the controller */
412 futex_wake(&parmap->thread_counter, INT_MAX);
417 * \brief Wakes all workers and waits for them to finish the tasks.
419 * This function is called by the controller thread.
421 * \param parmap a parmap
423 static void xbt_parmap_futex_master_signal(xbt_parmap_t parmap)
425 parmap->thread_counter = 1;
426 __sync_add_and_fetch(&parmap->work, 1);
427 /* wake all workers */
428 futex_wake(&parmap->work, INT_MAX);
432 * \brief Waits for some work to process.
434 * This function is called by each worker thread (not including the controller) when it has no more work to do.
436 * \param parmap a parmap
437 * \param round the expected round number
439 static void xbt_parmap_futex_worker_wait(xbt_parmap_t parmap, unsigned round)
441 unsigned work = parmap->work;
442 /* wait for more work */
443 while (work != round) {
444 futex_wait(&parmap->work, work);
451 * \brief Starts the parmap: waits for all workers to be ready and returns.
453 * This function is called by the controller thread.
455 * \param parmap a parmap
457 static void xbt_parmap_busy_master_wait(xbt_parmap_t parmap)
459 while (parmap->thread_counter < parmap->num_workers) {
460 xbt_os_thread_yield();
465 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
467 * This function is called by all worker threads when they end.
469 * \param parmap a parmap
471 static void xbt_parmap_busy_worker_signal(xbt_parmap_t parmap)
473 __sync_add_and_fetch(&parmap->thread_counter, 1);
477 * \brief Wakes all workers and waits for them to finish the tasks.
479 * This function is called by the controller thread.
481 * \param parmap a parmap
483 static void xbt_parmap_busy_master_signal(xbt_parmap_t parmap)
485 parmap->thread_counter = 1;
486 __sync_add_and_fetch(&parmap->work, 1);
490 * \brief Waits for some work to process.
492 * This function is called by each worker thread (not including the controller) when it has no more work to do.
494 * \param parmap a parmap
495 * \param round the expected round number
497 static void xbt_parmap_busy_worker_wait(xbt_parmap_t parmap, unsigned round)
499 /* wait for more work */
500 while (parmap->work != round) {
501 xbt_os_thread_yield();