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 including the controller */
53 void_f_pvoid_t fun; /* function to run in parallel on each element of data */
54 xbt_dynar_t data; /* parameters to pass to fun in parallel */
55 unsigned int index; /* index of the next element of data to pick */
59 * \brief Creates a parallel map object
60 * \param num_workers number of worker threads to create
61 * \return the parmap created
63 xbt_parmap_t xbt_parmap_new(unsigned int num_workers)
66 xbt_os_thread_t worker = NULL;
68 XBT_DEBUG("Create new parmap (%u workers)", num_workers);
70 /* Initialize the thread pool data structure */
71 xbt_parmap_t parmap = xbt_new0(s_xbt_parmap_t, 1);
73 parmap->num_workers = num_workers;
74 parmap->status = PARMAP_WORK;
76 /* Create the pool of worker threads */
77 for (i = 0; i < num_workers - 1; i++) {
78 worker = xbt_os_thread_create(NULL, xbt_parmap_worker_main, parmap, NULL);
79 xbt_os_thread_detach(worker);
81 xbt_parmap_start(parmap);
86 * \brief Destroys a parmap
87 * \param parmap the parmap to destroy
89 void xbt_parmap_destroy(xbt_parmap_t parmap)
91 parmap->status = PARMAP_DESTROY;
92 xbt_parmap_signal(parmap);
97 * \brief Applies a list of tasks in parallel.
98 * \param parmap a parallel map object
99 * \param fun the function to call in parallel
100 * \param data each element of this dynar will be passed as an argument to fun
102 void xbt_parmap_apply(xbt_parmap_t parmap, void_f_pvoid_t fun, xbt_dynar_t data)
104 /* Assign resources to worker threads */
108 xbt_parmap_signal(parmap);
109 XBT_DEBUG("Job done");
113 * \brief Returns a next task to process.
115 * Worker threads call this function to get more work.
117 * \return the next task to process, or NULL if there is no more work
119 void* xbt_parmap_next(xbt_parmap_t parmap)
121 unsigned int index = __sync_fetch_and_add(&parmap->index, 1);
122 if (index < xbt_dynar_length(parmap->data)) {
123 return xbt_dynar_get_as(parmap->data, index, void*);
129 * \brief Main function of a worker thread.
130 * \param arg the parmap
132 static void *xbt_parmap_worker_main(void *arg)
134 xbt_parmap_t parmap = (xbt_parmap_t) arg;
136 XBT_DEBUG("New worker thread created");
138 /* Worker's main loop */
140 xbt_parmap_wait(parmap);
141 if (parmap->status == PARMAP_WORK) {
143 XBT_DEBUG("Worker got a job");
145 void* work = xbt_parmap_next(parmap);
150 XBT_DEBUG("Worker has finished");
152 /* We are destroying the parmap */
154 xbt_parmap_end(parmap);
155 XBT_DEBUG("Shutting down worker");
162 static void futex_wait(int *uaddr, int val)
164 XBT_VERB("Waiting on futex %p", uaddr);
165 syscall(SYS_futex, uaddr, FUTEX_WAIT_PRIVATE, val, NULL, NULL, 0);
168 static void futex_wake(int *uaddr, int val)
170 XBT_VERB("Waking futex %p", uaddr);
171 syscall(SYS_futex, uaddr, FUTEX_WAKE_PRIVATE, val, NULL, NULL, 0);
176 * \brief Starts the parmap: waits for all workers to be ready and returns.
178 * This function is called by the controller thread.
180 * \param parmap a parmap
182 static void xbt_parmap_start(xbt_parmap_t parmap)
185 int myflag = parmap->done;
186 __sync_fetch_and_add(&parmap->thread_counter, 1);
187 if (parmap->thread_counter < parmap->num_workers) {
188 /* wait for all workers to be ready */
189 futex_wait(&parmap->done, myflag);
195 * \brief Wakes all workers and waits for them to finish the tasks.
197 * This function is called by the controller thread.
199 * \param parmap a parmap
201 static void xbt_parmap_signal(xbt_parmap_t parmap)
204 int myflag = parmap->done;
205 parmap->thread_counter = 0;
208 /* wake all workers */
209 futex_wake(&parmap->work, parmap->num_workers);
211 if (parmap->status == PARMAP_WORK) {
212 /* also work myself */
213 void* work = xbt_parmap_next(parmap);
219 unsigned int mycount = __sync_add_and_fetch(&parmap->thread_counter, 1);
220 if (mycount < parmap->num_workers) {
221 /* some workers have not finished yet */
222 futex_wait(&parmap->done, myflag);
229 * \brief Waits for some work to process.
231 * This function is called by each worker when it has no more work to do.
233 * \param parmap a parmap
235 static void xbt_parmap_wait(xbt_parmap_t parmap)
239 unsigned int mycount;
241 myflag = parmap->work;
242 mycount = __sync_add_and_fetch(&parmap->thread_counter, 1);
243 if (mycount == parmap->num_workers) {
244 /* all workers have finished, wake the controller */
246 futex_wake(&parmap->done, 1);
249 /* wait for more work */
250 futex_wait(&parmap->work, myflag);
255 * \brief Ends the parmap: wakes the controller thread when all workers terminate.
257 * This function is called by all worker threads when they end.
259 * \param parmap a parmap
261 static void xbt_parmap_end(xbt_parmap_t parmap)
264 unsigned int mycount;
266 mycount = __sync_add_and_fetch(&parmap->thread_counter, 1);
267 if (mycount == parmap->num_workers) {
268 /* all workers have finished, wake the controller */
270 futex_wake(&parmap->done, 1);
279 XBT_TEST_SUITE("parmap", "Parallel Map");
280 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(xbt_parmap_unit);
288 //XBT_INFO("I'm job %lu", (unsigned long)arg);
291 XBT_TEST_UNIT("basic", test_parmap_basic, "Basic usage")
293 xbt_test_add("Create the parmap");
296 xbt_dynar_t data = xbt_dynar_new(sizeof(void *), NULL);
298 /* Create the parallel map */
299 parmap = xbt_parmap_new(10);
301 for (j = 0; j < 100; j++) {
302 xbt_dynar_push_as(data, void *, (void *)j);
305 for (i = 0; i < 5; i++) {
306 xbt_parmap_apply(parmap, fun, data);
309 /* Destroy the parmap */
310 xbt_parmap_destroy(parmap);
311 xbt_dynar_free(&data);
314 #endif /* SIMGRID_TEST */