1 /* Copyright (c) 2004, 2005, 2007, 2009, 2010. 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. */
6 #include "gras_config.h"
10 #include <sys/syscall.h>
14 #include <linux/futex.h>
17 #include "xbt/parmap.h"
19 #include "xbt/function_types.h"
20 #include "xbt/dynar.h"
21 #include "xbt/xbt_os_thread.h"
22 #include "xbt/sysdep.h"
24 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_parmap, xbt, "parmap: parallel map");
25 XBT_LOG_NEW_SUBCATEGORY(xbt_parmap_unit, xbt_parmap, "parmap unit testing");
30 } e_xbt_parmap_flag_t;
32 static void xbt_parmap_set_mode(xbt_parmap_t parmap, e_xbt_parmap_mode_t mode);
33 static void *xbt_parmap_worker_main(void *parmap);
35 static void xbt_parmap_posix_start(xbt_parmap_t parmap);
36 static void xbt_parmap_posix_end(xbt_parmap_t parmap);
37 static void xbt_parmap_posix_signal(xbt_parmap_t parmap);
38 static void xbt_parmap_posix_wait(xbt_parmap_t parmap);
41 static void xbt_parmap_futex_start(xbt_parmap_t parmap);
42 static void xbt_parmap_futex_end(xbt_parmap_t parmap);
43 static void xbt_parmap_futex_signal(xbt_parmap_t parmap);
44 static void xbt_parmap_futex_wait(xbt_parmap_t parmap);
45 static void futex_wait(int *uaddr, int val);
46 static void futex_wake(int *uaddr, int val);
49 static void xbt_parmap_busy_start(xbt_parmap_t parmap);
50 static void xbt_parmap_busy_end(xbt_parmap_t parmap);
51 static void xbt_parmap_busy_signal(xbt_parmap_t parmap);
52 static void xbt_parmap_busy_wait(xbt_parmap_t parmap);
56 * \brief Parallel map structure
58 typedef struct s_xbt_parmap {
59 e_xbt_parmap_flag_t status; /**< is the parmap active or being destroyed? */
60 int work; /**< index of the current round (1 is the first) */
61 int done; /**< number of rounds already done (futexes only) */
62 unsigned int thread_counter; /**< number of threads currently working */
63 unsigned int num_workers; /**< total number of worker threads including the controller */
64 void_f_pvoid_t fun; /**< function to run in parallel on each element of data */
65 xbt_dynar_t data; /**< parameters to pass to fun in parallel */
66 unsigned int index; /**< index of the next element of data to pick */
68 /* fields that depend on the synchronization mode */
69 e_xbt_parmap_mode_t mode; /**< synchronization mode */
70 void (*start_f)(xbt_parmap_t); /**< initializes the worker threads */
71 void (*end_f)(xbt_parmap_t); /**< finalizes the worker threads */
72 void (*signal_f)(xbt_parmap_t); /**< wakes the workers threads to process tasks */
73 void (*wait_f)(xbt_parmap_t); /**< waits for more work */
77 * \brief Creates a parallel map object
78 * \param num_workers number of worker threads to create
79 * \param mode how to synchronize the worker threads
80 * \return the parmap created
82 xbt_parmap_t xbt_parmap_new(unsigned int num_workers, e_xbt_parmap_mode_t mode)
85 xbt_os_thread_t worker = NULL;
87 XBT_DEBUG("Create new parmap (%u workers)", num_workers);
89 /* Initialize the thread pool data structure */
90 xbt_parmap_t parmap = xbt_new0(s_xbt_parmap_t, 1);
92 parmap->num_workers = num_workers;
93 parmap->status = XBT_PARMAP_WORK;
94 xbt_parmap_set_mode(parmap, mode);
96 /* Create the pool of worker threads */
97 for (i = 0; i < num_workers - 1; i++) {
98 worker = xbt_os_thread_create(NULL, xbt_parmap_worker_main, parmap, NULL);
99 xbt_os_thread_detach(worker);
101 parmap->start_f(parmap);
106 * \brief Destroys a parmap
107 * \param parmap the parmap to destroy
109 void xbt_parmap_destroy(xbt_parmap_t parmap)
111 parmap->status = XBT_PARMAP_DESTROY;
112 parmap->signal_f(parmap);
117 * \brief Sets the synchronization mode of a parmap.
118 * \param parmap a parallel map object
119 * \param mode the synchronization mode
121 static void xbt_parmap_set_mode(xbt_parmap_t parmap, e_xbt_parmap_mode_t mode)
123 if (mode == XBT_PARMAP_DEFAULT) {
125 mode = XBT_PARMAP_FUTEX;
127 mode = XBT_PARMAP_POSIX;
134 case XBT_PARMAP_POSIX:
135 parmap->start_f = xbt_parmap_posix_start;
136 parmap->end_f = xbt_parmap_posix_end;
137 parmap->signal_f = xbt_parmap_posix_signal;
138 parmap->wait_f = xbt_parmap_posix_wait;
142 case XBT_PARMAP_FUTEX:
144 parmap->start_f = xbt_parmap_futex_start;
145 parmap->end_f = xbt_parmap_futex_end;
146 parmap->signal_f = xbt_parmap_futex_signal;
147 parmap->wait_f = xbt_parmap_futex_wait;
150 xbt_die("Futex is not available on this OS (maybe you are on a Mac).");
153 case XBT_PARMAP_BUSY_WAIT:
154 parmap->start_f = xbt_parmap_busy_start;
155 parmap->end_f = xbt_parmap_busy_end;
156 parmap->signal_f = xbt_parmap_busy_signal;
157 parmap->wait_f = xbt_parmap_busy_wait;
160 case XBT_PARMAP_DEFAULT:
167 * \brief Applies a list of tasks in parallel.
168 * \param parmap a parallel map object
169 * \param fun the function to call in parallel
170 * \param data each element of this dynar will be passed as an argument to fun
172 void xbt_parmap_apply(xbt_parmap_t parmap, void_f_pvoid_t fun, xbt_dynar_t data)
174 /* Assign resources to worker threads */
178 parmap->signal_f(parmap);
179 XBT_DEBUG("Job done");
183 * \brief Returns a next task to process.
185 * Worker threads call this function to get more work.
187 * \return the next task to process, or NULL if there is no more work
189 void* xbt_parmap_next(xbt_parmap_t parmap)
191 unsigned int index = __sync_fetch_and_add(&parmap->index, 1);
192 if (index < xbt_dynar_length(parmap->data)) {
193 return xbt_dynar_get_as(parmap->data, index, void*);
199 * \brief Main function of a worker thread.
200 * \param arg the parmap
202 static void *xbt_parmap_worker_main(void *arg)
204 xbt_parmap_t parmap = (xbt_parmap_t) arg;
206 XBT_DEBUG("New worker thread created");
208 /* Worker's main loop */
210 parmap->wait_f(parmap);
211 if (parmap->status == XBT_PARMAP_WORK) {
213 XBT_DEBUG("Worker got a job");
215 void* work = xbt_parmap_next(parmap);
216 while (work != NULL) {
218 work = xbt_parmap_next(parmap);
221 XBT_DEBUG("Worker has finished");
223 /* We are destroying the parmap */
225 parmap->end_f(parmap);
226 XBT_DEBUG("Shutting down worker");
233 static void futex_wait(int *uaddr, int val)
235 XBT_VERB("Waiting on futex %p", uaddr);
236 syscall(SYS_futex, uaddr, FUTEX_WAIT_PRIVATE, val, NULL, NULL, 0);
239 static void futex_wake(int *uaddr, int val)
241 XBT_VERB("Waking futex %p", uaddr);
242 syscall(SYS_futex, uaddr, FUTEX_WAKE_PRIVATE, val, NULL, NULL, 0);
246 static void xbt_parmap_posix_start(xbt_parmap_t parmap)
251 static void xbt_parmap_posix_end(xbt_parmap_t parmap)
256 static void xbt_parmap_posix_signal(xbt_parmap_t parmap)
261 static void xbt_parmap_posix_wait(xbt_parmap_t parmap)
268 * \brief Starts the parmap: waits for all workers to be ready and returns.
270 * This function is called by the controller thread.
272 * \param parmap a parmap
274 static void xbt_parmap_futex_start(xbt_parmap_t parmap)
276 int myflag = parmap->done;
277 __sync_fetch_and_add(&parmap->thread_counter, 1);
278 if (parmap->thread_counter < parmap->num_workers) {
279 /* wait for all workers to be ready */
280 futex_wait(&parmap->done, myflag);
285 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
287 * This function is called by all worker threads when they end (not including
290 * \param parmap a parmap
292 static void xbt_parmap_futex_end(xbt_parmap_t parmap)
294 unsigned int mycount;
296 mycount = __sync_add_and_fetch(&parmap->thread_counter, 1);
297 if (mycount == parmap->num_workers) {
298 /* all workers have finished, wake the controller */
300 futex_wake(&parmap->done, 1);
305 * \brief Wakes all workers and waits for them to finish the tasks.
307 * This function is called by the controller thread.
309 * \param parmap a parmap
311 static void xbt_parmap_futex_signal(xbt_parmap_t parmap)
313 int myflag = parmap->done;
314 parmap->thread_counter = 0;
317 /* wake all workers */
318 futex_wake(&parmap->work, parmap->num_workers);
320 if (parmap->status == XBT_PARMAP_WORK) {
321 /* also work myself */
322 void* work = xbt_parmap_next(parmap);
323 while (work != NULL) {
325 work = xbt_parmap_next(parmap);
329 unsigned int mycount = __sync_add_and_fetch(&parmap->thread_counter, 1);
330 if (mycount < parmap->num_workers) {
331 /* some workers have not finished yet */
332 futex_wait(&parmap->done, myflag);
337 * \brief Waits for some work to process.
339 * This function is called by each worker thread (not including the controller)
340 * when it has no more work to do.
342 * \param parmap a parmap
344 static void xbt_parmap_futex_wait(xbt_parmap_t parmap)
347 unsigned int mycount;
349 myflag = parmap->work;
350 mycount = __sync_add_and_fetch(&parmap->thread_counter, 1);
351 if (mycount == parmap->num_workers) {
352 /* all workers have finished, wake the controller */
354 futex_wake(&parmap->done, 1);
357 /* wait for more work */
358 futex_wait(&parmap->work, myflag);
363 * \brief Starts the parmap: waits for all workers to be ready and returns.
365 * This function is called by the controller thread.
367 * \param parmap a parmap
369 static void xbt_parmap_busy_start(xbt_parmap_t parmap)
371 __sync_fetch_and_add(&parmap->thread_counter, 1);
372 while (parmap->thread_counter < parmap->num_workers) {
373 xbt_os_thread_yield();
378 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
380 * This function is called by all worker threads when they end.
382 * \param parmap a parmap
384 static void xbt_parmap_busy_end(xbt_parmap_t parmap)
386 __sync_add_and_fetch(&parmap->thread_counter, 1);
390 * \brief Wakes all workers and waits for them to finish the tasks.
392 * This function is called by the controller thread.
394 * \param parmap a parmap
396 static void xbt_parmap_busy_signal(xbt_parmap_t parmap)
398 parmap->thread_counter = 0;
401 if (parmap->status == XBT_PARMAP_WORK) {
402 /* also work myself */
403 void* work = xbt_parmap_next(parmap);
404 while (work != NULL) {
406 work = xbt_parmap_next(parmap);
410 /* I have finished, wait for the others */
411 __sync_add_and_fetch(&parmap->thread_counter, 1);
412 while (parmap->thread_counter < parmap->num_workers) {
413 xbt_os_thread_yield();
418 * \brief Waits for some work to process.
420 * This function is called by each worker thread (not including the controller)
421 * when it has no more work to do.
423 * \param parmap a parmap
425 static void xbt_parmap_busy_wait(xbt_parmap_t parmap)
427 int work = parmap->work;
428 __sync_add_and_fetch(&parmap->thread_counter, 1);
430 /* wait for more work */
431 while (parmap->work == work) {
432 xbt_os_thread_yield();
440 XBT_TEST_SUITE("parmap", "Parallel Map");
441 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(xbt_parmap_unit);
449 //XBT_INFO("I'm job %lu", (unsigned long)arg);
452 XBT_TEST_UNIT("basic", test_parmap_basic, "Basic usage")
454 xbt_test_add("Create the parmap");
457 xbt_dynar_t data = xbt_dynar_new(sizeof(void *), NULL);
459 /* Create the parallel map */
461 parmap = xbt_parmap_new(10, XBT_PARMAP_FUTEX);
463 parmap = xbt_parmap_new(10, XBT_PARMAP_BUSY_WAIT);
465 for (j = 0; j < 100; j++) {
466 xbt_dynar_push_as(data, void *, (void *)j);
469 for (i = 0; i < 5; i++) {
470 xbt_parmap_apply(parmap, fun, data);
473 /* Destroy the parmap */
474 xbt_parmap_destroy(parmap);
475 xbt_dynar_free(&data);
478 #endif /* SIMGRID_TEST */