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"
30 #include "src/simix/smx_private.hpp"
32 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_parmap, xbt, "parmap: parallel map");
37 } e_xbt_parmap_flag_t;
39 static void xbt_parmap_set_mode(xbt_parmap_t parmap, e_xbt_parmap_mode_t mode);
40 static void *xbt_parmap_worker_main(void *parmap);
41 static void xbt_parmap_work(xbt_parmap_t parmap);
43 static void xbt_parmap_posix_master_wait(xbt_parmap_t parmap);
44 static void xbt_parmap_posix_worker_signal(xbt_parmap_t parmap);
45 static void xbt_parmap_posix_master_signal(xbt_parmap_t parmap);
46 static void xbt_parmap_posix_worker_wait(xbt_parmap_t parmap, unsigned round);
49 static void xbt_parmap_futex_master_wait(xbt_parmap_t parmap);
50 static void xbt_parmap_futex_worker_signal(xbt_parmap_t parmap);
51 static void xbt_parmap_futex_master_signal(xbt_parmap_t parmap);
52 static void xbt_parmap_futex_worker_wait(xbt_parmap_t parmap, unsigned round);
53 static void futex_wait(unsigned *uaddr, unsigned val);
54 static void futex_wake(unsigned *uaddr, unsigned val);
57 static void xbt_parmap_busy_master_wait(xbt_parmap_t parmap);
58 static void xbt_parmap_busy_worker_signal(xbt_parmap_t parmap);
59 static void xbt_parmap_busy_master_signal(xbt_parmap_t parmap);
60 static void xbt_parmap_busy_worker_wait(xbt_parmap_t parmap, unsigned round);
63 * \brief Parallel map structure
65 typedef struct s_xbt_parmap {
66 e_xbt_parmap_flag_t status; /**< is the parmap active or being destroyed? */
67 unsigned work; /**< index of the current round */
68 unsigned thread_counter; /**< number of workers that have done the work */
70 unsigned int num_workers; /**< total number of worker threads including the controller */
71 xbt_os_thread_t *workers; /**< worker thread handlers */
72 void_f_pvoid_t fun; /**< function to run in parallel on each element of data */
73 xbt_dynar_t data; /**< parameters to pass to fun in parallel */
74 std::atomic<unsigned int> index; /**< index of the next element of data to pick */
77 xbt_os_cond_t ready_cond;
78 xbt_os_mutex_t ready_mutex;
79 xbt_os_cond_t done_cond;
80 xbt_os_mutex_t done_mutex;
82 /* fields that depend on the synchronization mode */
83 e_xbt_parmap_mode_t mode; /**< synchronization mode */
84 void (*master_wait_f)(xbt_parmap_t); /**< wait for the workers to have done the work */
85 void (*worker_signal_f)(xbt_parmap_t); /**< signal the master that a worker has done the work */
86 void (*master_signal_f)(xbt_parmap_t); /**< wakes the workers threads to process tasks */
87 void (*worker_wait_f)(xbt_parmap_t, unsigned); /**< waits for more work */
91 * \brief Thread data transmission structure
93 typedef struct s_xbt_parmap_thread_data{
96 } s_xbt_parmap_thread_data_t;
98 typedef s_xbt_parmap_thread_data_t *xbt_parmap_thread_data_t;
101 * \brief Creates a parallel map object
102 * \param num_workers number of worker threads to create
103 * \param mode how to synchronize the worker threads
104 * \return the parmap created
106 xbt_parmap_t xbt_parmap_new(unsigned int num_workers, e_xbt_parmap_mode_t mode)
108 XBT_DEBUG("Create new parmap (%u workers)", num_workers);
110 /* Initialize the thread pool data structure */
111 xbt_parmap_t parmap = new s_xbt_parmap_t();
112 parmap->workers = xbt_new(xbt_os_thread_t, num_workers);
114 parmap->num_workers = num_workers;
115 parmap->status = XBT_PARMAP_WORK;
116 xbt_parmap_set_mode(parmap, mode);
118 /* Create the pool of worker threads */
119 xbt_parmap_thread_data_t data;
120 parmap->workers[0] = NULL;
121 #if HAVE_PTHREAD_SETAFFINITY
124 for (unsigned int i = 1; i < num_workers; i++) {
125 data = xbt_new0(s_xbt_parmap_thread_data_t, 1);
126 data->parmap = parmap;
128 parmap->workers[i] = xbt_os_thread_create(NULL, xbt_parmap_worker_main, data, NULL);
129 #if HAVE_PTHREAD_SETAFFINITY
130 xbt_os_thread_bind(parmap->workers[i], core_bind);
131 if (core_bind != xbt_os_get_numcores())
141 * \brief Destroys a parmap
142 * \param parmap the parmap to destroy
144 void xbt_parmap_destroy(xbt_parmap_t parmap)
150 parmap->status = XBT_PARMAP_DESTROY;
151 parmap->master_signal_f(parmap);
154 for (i = 1; i < parmap->num_workers; i++)
155 xbt_os_thread_join(parmap->workers[i], NULL);
157 xbt_os_cond_destroy(parmap->ready_cond);
158 xbt_os_mutex_destroy(parmap->ready_mutex);
159 xbt_os_cond_destroy(parmap->done_cond);
160 xbt_os_mutex_destroy(parmap->done_mutex);
162 xbt_free(parmap->workers);
167 * \brief Sets the synchronization mode of a parmap.
168 * \param parmap a parallel map object
169 * \param mode the synchronization mode
171 static void xbt_parmap_set_mode(xbt_parmap_t parmap, e_xbt_parmap_mode_t mode)
173 if (mode == XBT_PARMAP_DEFAULT) {
175 mode = XBT_PARMAP_FUTEX;
177 mode = XBT_PARMAP_POSIX;
183 case XBT_PARMAP_POSIX:
184 parmap->master_wait_f = xbt_parmap_posix_master_wait;
185 parmap->worker_signal_f = xbt_parmap_posix_worker_signal;
186 parmap->master_signal_f = xbt_parmap_posix_master_signal;
187 parmap->worker_wait_f = xbt_parmap_posix_worker_wait;
189 parmap->ready_cond = xbt_os_cond_init();
190 parmap->ready_mutex = xbt_os_mutex_init();
191 parmap->done_cond = xbt_os_cond_init();
192 parmap->done_mutex = xbt_os_mutex_init();
194 case XBT_PARMAP_FUTEX:
196 parmap->master_wait_f = xbt_parmap_futex_master_wait;
197 parmap->worker_signal_f = xbt_parmap_futex_worker_signal;
198 parmap->master_signal_f = xbt_parmap_futex_master_signal;
199 parmap->worker_wait_f = xbt_parmap_futex_worker_wait;
201 xbt_os_cond_destroy(parmap->ready_cond);
202 xbt_os_mutex_destroy(parmap->ready_mutex);
203 xbt_os_cond_destroy(parmap->done_cond);
204 xbt_os_mutex_destroy(parmap->done_mutex);
207 xbt_die("Futex is not available on this OS.");
209 case XBT_PARMAP_BUSY_WAIT:
210 parmap->master_wait_f = xbt_parmap_busy_master_wait;
211 parmap->worker_signal_f = xbt_parmap_busy_worker_signal;
212 parmap->master_signal_f = xbt_parmap_busy_master_signal;
213 parmap->worker_wait_f = xbt_parmap_busy_worker_wait;
215 xbt_os_cond_destroy(parmap->ready_cond);
216 xbt_os_mutex_destroy(parmap->ready_mutex);
217 xbt_os_cond_destroy(parmap->done_cond);
218 xbt_os_mutex_destroy(parmap->done_mutex);
220 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 NULL 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)
263 while ((index = parmap->index++) < xbt_dynar_length(parmap->data))
264 parmap->fun(xbt_dynar_get_as(parmap->data, index, void*));
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 = (xbt_parmap_thread_data_t) arg;
274 xbt_parmap_t parmap = data->parmap;
276 smx_context_t context = SIMIX_context_new(NULL, 0, NULL, NULL, NULL);
277 SIMIX_context_set_current(context);
279 XBT_DEBUG("New worker thread created");
281 /* Worker's main loop */
283 parmap->worker_wait_f(parmap, ++round);
284 if (parmap->status == XBT_PARMAP_WORK) {
285 XBT_DEBUG("Worker %d got a job", data->worker_id);
287 xbt_parmap_work(parmap);
288 parmap->worker_signal_f(parmap);
290 XBT_DEBUG("Worker %d has finished", data->worker_id);
291 /* We are destroying the parmap */
293 SIMIX_context_free(context);
301 static void futex_wait(unsigned *uaddr, unsigned val)
303 XBT_VERB("Waiting on futex %p", uaddr);
304 syscall(SYS_futex, uaddr, FUTEX_WAIT_PRIVATE, val, NULL, NULL, 0);
307 static void futex_wake(unsigned *uaddr, unsigned val)
309 XBT_VERB("Waking futex %p", uaddr);
310 syscall(SYS_futex, uaddr, FUTEX_WAKE_PRIVATE, val, NULL, NULL, 0);
315 * \brief Starts the parmap: waits for all workers to be ready and returns.
317 * This function is called by the controller thread.
319 * \param parmap a parmap
321 static void xbt_parmap_posix_master_wait(xbt_parmap_t parmap)
323 xbt_os_mutex_acquire(parmap->done_mutex);
324 if (parmap->thread_counter < parmap->num_workers) {
325 /* wait for all workers to be ready */
326 xbt_os_cond_wait(parmap->done_cond, parmap->done_mutex);
328 xbt_os_mutex_release(parmap->done_mutex);
332 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
334 * This function is called by all worker threads when they end (not including the controller).
336 * \param parmap a parmap
338 static void xbt_parmap_posix_worker_signal(xbt_parmap_t parmap)
340 xbt_os_mutex_acquire(parmap->done_mutex);
341 if (++parmap->thread_counter == parmap->num_workers) {
342 /* all workers have finished, wake the controller */
343 xbt_os_cond_signal(parmap->done_cond);
345 xbt_os_mutex_release(parmap->done_mutex);
349 * \brief Wakes all workers and waits for them to finish the tasks.
351 * This function is called by the controller thread.
353 * \param parmap a parmap
355 static void xbt_parmap_posix_master_signal(xbt_parmap_t parmap)
357 xbt_os_mutex_acquire(parmap->ready_mutex);
358 parmap->thread_counter = 1;
360 /* wake all workers */
361 xbt_os_cond_broadcast(parmap->ready_cond);
362 xbt_os_mutex_release(parmap->ready_mutex);
366 * \brief Waits for some work to process.
368 * This function is called by each worker thread (not including the controller) when it has no more work to do.
370 * \param parmap a parmap
371 * \param round the expected round number
373 static void xbt_parmap_posix_worker_wait(xbt_parmap_t parmap, unsigned round)
375 xbt_os_mutex_acquire(parmap->ready_mutex);
376 /* wait for more work */
377 if (parmap->work != round) {
378 xbt_os_cond_wait(parmap->ready_cond, parmap->ready_mutex);
380 xbt_os_mutex_release(parmap->ready_mutex);
385 * \brief Starts the parmap: waits for all workers to be ready and returns.
387 * This function is called by the controller thread.
389 * \param parmap a parmap
391 static void xbt_parmap_futex_master_wait(xbt_parmap_t parmap)
393 unsigned count = parmap->thread_counter;
394 while (count < parmap->num_workers) {
395 /* wait for all workers to be ready */
396 futex_wait(&parmap->thread_counter, count);
397 count = parmap->thread_counter;
402 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
404 * This function is called by all worker threads when they end (not including the controller).
406 * \param parmap a parmap
408 static void xbt_parmap_futex_worker_signal(xbt_parmap_t parmap)
410 unsigned count = __sync_add_and_fetch(&parmap->thread_counter, 1);
411 if (count == parmap->num_workers) {
412 /* all workers have finished, wake the controller */
413 futex_wake(&parmap->thread_counter, INT_MAX);
418 * \brief Wakes all workers and waits for them to finish the tasks.
420 * This function is called by the controller thread.
422 * \param parmap a parmap
424 static void xbt_parmap_futex_master_signal(xbt_parmap_t parmap)
426 parmap->thread_counter = 1;
427 __sync_add_and_fetch(&parmap->work, 1);
428 /* wake all workers */
429 futex_wake(&parmap->work, INT_MAX);
433 * \brief Waits for some work to process.
435 * This function is called by each worker thread (not including the controller) when it has no more work to do.
437 * \param parmap a parmap
438 * \param round the expected round number
440 static void xbt_parmap_futex_worker_wait(xbt_parmap_t parmap, unsigned round)
442 unsigned work = parmap->work;
443 /* wait for more work */
444 while (work != round) {
445 futex_wait(&parmap->work, work);
452 * \brief Starts the parmap: waits for all workers to be ready and returns.
454 * This function is called by the controller thread.
456 * \param parmap a parmap
458 static void xbt_parmap_busy_master_wait(xbt_parmap_t parmap)
460 while (parmap->thread_counter < parmap->num_workers) {
461 xbt_os_thread_yield();
466 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
468 * This function is called by all worker threads when they end.
470 * \param parmap a parmap
472 static void xbt_parmap_busy_worker_signal(xbt_parmap_t parmap)
474 __sync_add_and_fetch(&parmap->thread_counter, 1);
478 * \brief Wakes all workers and waits for them to finish the tasks.
480 * This function is called by the controller thread.
482 * \param parmap a parmap
484 static void xbt_parmap_busy_master_signal(xbt_parmap_t parmap)
486 parmap->thread_counter = 1;
487 __sync_add_and_fetch(&parmap->work, 1);
491 * \brief Waits for some work to process.
493 * This function is called by each worker thread (not including the controller) when it has no more work to do.
495 * \param parmap a parmap
496 * \param round the expected round number
498 static void xbt_parmap_busy_worker_wait(xbt_parmap_t parmap, unsigned round)
500 /* wait for more work */
501 while (parmap->work != round) {
502 xbt_os_thread_yield();