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_start(xbt_parmap_t parmap);
33 static void xbt_parmap_signal(xbt_parmap_t parmap);
34 static void xbt_parmap_wait(xbt_parmap_t parmap);
35 static void xbt_parmap_end(xbt_parmap_t parmap);
36 static void *xbt_parmap_worker_main(void *parmap);
39 static void futex_wait(int *uaddr, int val);
40 static void futex_wake(int *uaddr, int val);
44 * \brief Parallel map structure
46 typedef struct s_xbt_parmap {
47 e_xbt_parmap_flag_t status; /* is the parmap active or being destroyed? */
49 int work; /* index of the current round (1 is the first) */
50 int done; /* number of rounds already done */
51 unsigned int thread_counter; /* number of threads currently working */
52 unsigned int num_workers; /* total number of worker threads */
53 unsigned int workers_max_id; /* id of the next worker thread to create */
54 void_f_pvoid_t fun; /* function to run in parallel on each element of data */
55 xbt_dynar_t data; /* parameters to pass to fun in parallel */
56 unsigned int index; /* index of the next element of data to pick */
60 * \brief Creates a parallel map object
61 * \param num_workers number of worker threads to create
62 * \return the parmap created
64 xbt_parmap_t xbt_parmap_new(unsigned int num_workers)
67 xbt_os_thread_t worker = NULL;
69 XBT_DEBUG("Create new parmap (%u workers)", num_workers);
71 /* Initialize the thread pool data structure */
72 xbt_parmap_t parmap = xbt_new0(s_xbt_parmap_t, 1);
74 parmap->num_workers = num_workers;
75 parmap->status = PARMAP_WORK;
77 /* Create the pool of worker threads */
78 for (i = 0; i < num_workers; i++) {
79 worker = xbt_os_thread_create(NULL, xbt_parmap_worker_main, parmap, NULL);
80 xbt_os_thread_detach(worker);
82 xbt_parmap_start(parmap);
87 * \brief Destroys a parmap
88 * \param parmap the parmap to destroy
90 void xbt_parmap_destroy(xbt_parmap_t parmap)
92 parmap->status = PARMAP_DESTROY;
93 xbt_parmap_signal(parmap);
98 * \brief Applies a list of tasks in parallel.
99 * \param parmap a parallel map object
100 * \param fun the function to call in parallel
101 * \param data each element of this dynar will be passed as an argument to fun
103 void xbt_parmap_apply(xbt_parmap_t parmap, void_f_pvoid_t fun, xbt_dynar_t data)
105 /* Assign resources to worker threads*/
109 xbt_parmap_signal(parmap);
110 XBT_DEBUG("Job done");
114 * \brief Returns a next task to process.
116 * Worker threads call this function to get more work.
118 * \return the next task to process, or NULL if there is no more work
120 void* xbt_parmap_next(xbt_parmap_t parmap)
122 unsigned int index = __sync_fetch_and_add(&parmap->index, 1);
123 if (index < xbt_dynar_length(parmap->data)) {
124 return xbt_dynar_get_as(parmap->data, index, void*);
130 * \brief Returns the worker id of the current thread.
131 * \param parmap a parmap
132 * \return the worker id
134 unsigned long xbt_parmap_get_worker_id(xbt_parmap_t parmap)
136 return (unsigned long) xbt_os_thread_get_extra_data();
140 * \brief Main function of a worker thread.
141 * \param arg the parmap
143 static void *xbt_parmap_worker_main(void *arg)
145 unsigned int worker_id;
146 xbt_parmap_t parmap = (xbt_parmap_t) arg;
148 /* Fetch a worker id */
149 worker_id = __sync_fetch_and_add(&parmap->workers_max_id, 1);
150 xbt_os_thread_set_extra_data((void*) (unsigned long) worker_id);
152 XBT_DEBUG("New worker thread created (%u)", worker_id);
154 /* Worker's main loop */
156 xbt_parmap_wait(parmap);
157 if (parmap->status == PARMAP_WORK) {
159 XBT_DEBUG("Worker %u got a job", worker_id);
161 void* work = xbt_parmap_next(parmap);
166 XBT_DEBUG("Worker %u has finished", worker_id);
168 /* We are destroying the parmap */
170 xbt_parmap_end(parmap);
171 XBT_DEBUG("Shutting down worker %u", worker_id);
178 static void futex_wait(int *uaddr, int val)
180 XBT_VERB("Waiting on futex %p", uaddr);
181 syscall(SYS_futex, uaddr, FUTEX_WAIT_PRIVATE, val, NULL, NULL, 0);
184 static void futex_wake(int *uaddr, int val)
186 XBT_VERB("Waking futex %p", uaddr);
187 syscall(SYS_futex, uaddr, FUTEX_WAKE_PRIVATE, val, NULL, NULL, 0);
192 * \brief Starts the parmap: waits for all workers to be ready and returns.
194 * This function is called by the controller thread.
196 * \param parmap a parmap
198 static void xbt_parmap_start(xbt_parmap_t parmap)
201 int myflag = parmap->done;
202 if (parmap->thread_counter < parmap->num_workers) {
203 /* wait for all workers to be ready */
204 futex_wait(&parmap->done, myflag);
210 * \brief Wakes all workers and waits for them to finish the tasks.
212 * This function is called by the controller thread.
214 * \param parmap a parmap
216 static void xbt_parmap_signal(xbt_parmap_t parmap)
219 int myflag = parmap->done;
220 parmap->thread_counter = 0;
223 /* wake all workers */
224 futex_wake(&parmap->work, parmap->num_workers);
226 /* wait for all of them to finish */
227 futex_wait(&parmap->done, myflag);
232 * \brief Waits for some work to process.
234 * This function is called by each worker when it has no more work to do.
236 * \param parmap a parmap
238 static void xbt_parmap_wait(xbt_parmap_t parmap)
242 unsigned int mycount;
244 myflag = parmap->work;
245 mycount = __sync_add_and_fetch(&parmap->thread_counter, 1);
246 if (mycount == parmap->num_workers) {
247 /* all workers have finished, wake the controller */
249 futex_wake(&parmap->done, 1);
252 /* wait for more work */
253 futex_wait(&parmap->work, myflag);
258 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
260 * This function is called by all worker threads when they end.
262 * \param parmap a parmap
264 static void xbt_parmap_end(xbt_parmap_t parmap)
267 unsigned int mycount;
269 mycount = __sync_add_and_fetch(&parmap->thread_counter, 1);
270 if (mycount == parmap->num_workers) {
271 /* all workers have finished, wake the controller */
273 futex_wake(&parmap->done, 1);
282 XBT_TEST_SUITE("parmap", "Parallel Map");
283 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(xbt_parmap_unit);
291 //XBT_INFO("I'm job %lu", (unsigned long)arg);
294 XBT_TEST_UNIT("basic", test_parmap_basic, "Basic usage")
296 xbt_test_add("Create the parmap");
299 xbt_dynar_t data = xbt_dynar_new(sizeof(void *), NULL);
301 /* Create the parallel map */
302 parmap = xbt_parmap_new(10);
304 for(j = 0; j < 100; j++) {
305 xbt_dynar_push_as(data, void *, (void *)j);
308 for (i = 0; i < 5; i++) {
309 xbt_parmap_apply(parmap, fun, data);
312 /* Destroy the parmap */
313 xbt_parmap_destroy(parmap);
314 xbt_dynar_free(&data);
317 #endif /* SIMGRID_TEST */