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"
8 #include <sys/syscall.h>
10 #include <linux/futex.h>
12 #include "xbt/xbt_os_thread.h"
15 #include "parmap_private.h"
17 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_parmap, xbt, "parmap: parallel map");
18 XBT_LOG_NEW_SUBCATEGORY(xbt_parmap_unit, xbt_parmap, "parmap unit testing");
20 static void *_xbt_parmap_worker_main(void *parmap);
22 static void futex_wait(int *uaddr, int val);
23 static void futex_wake(int *uaddr, int val);
25 xbt_parmap_t xbt_parmap_new(unsigned int num_workers)
28 xbt_os_thread_t worker = NULL;
30 DEBUG1("Create new parmap (%u workers)", num_workers);
32 /* Initialize the thread pool data structure */
33 xbt_parmap_t parmap = xbt_new0(s_xbt_parmap_t, 1);
34 parmap->num_workers = num_workers;
35 parmap->status = PARMAP_WORK;
37 parmap->workers_ready = xbt_new0(s_xbt_barrier_t, 1);
38 xbt_barrier_init(parmap->workers_ready, num_workers + 1);
39 parmap->workers_done = xbt_new0(s_xbt_barrier_t, 1);
40 xbt_barrier_init(parmap->workers_done, num_workers + 1);
42 parmap->workers_ready->mutex = xbt_os_mutex_init();
43 parmap->workers_ready->cond = xbt_os_cond_init();
45 /* Create the pool of worker threads */
46 for(i=0; i < num_workers; i++){
47 worker = xbt_os_thread_create(NULL, _xbt_parmap_worker_main, parmap, NULL);
48 xbt_os_thread_detach(worker);
54 void xbt_parmap_destroy(xbt_parmap_t parmap)
56 DEBUG1("Destroy parmap %p", parmap);
58 parmap->status = PARMAP_DESTROY;
60 xbt_barrier_wait(parmap->workers_ready);
61 DEBUG0("Kill job sent");
62 xbt_barrier_wait(parmap->workers_done);
64 xbt_os_mutex_destroy(parmap->workers_ready->mutex);
65 xbt_os_cond_destroy(parmap->workers_ready->cond);
67 xbt_free(parmap->workers_ready);
68 xbt_free(parmap->workers_done);
72 void xbt_parmap_apply(xbt_parmap_t parmap, void_f_pvoid_t fun, xbt_dynar_t data)
74 /* Assign resources to worker threads*/
78 /* Notify workers that there is a job */
79 xbt_barrier_wait(parmap->workers_ready);
80 DEBUG0("Job dispatched, lets wait...");
81 xbt_barrier_wait(parmap->workers_done);
88 static void *_xbt_parmap_worker_main(void *arg)
90 unsigned int data_start, data_end, data_size, worker_id;
91 xbt_parmap_t parmap = (xbt_parmap_t)arg;
93 /* Fetch a worker id */
94 worker_id = __sync_fetch_and_add(&parmap->workers_max_id, 1);
96 DEBUG1("New worker thread created (%u)", worker_id);
98 /* Worker's main loop */
100 xbt_barrier_wait(parmap->workers_ready);
102 if(parmap->status == PARMAP_WORK){
103 DEBUG1("Worker %u got a job", worker_id);
105 /* Compute how much data does every worker gets */
106 data_size = (xbt_dynar_length(parmap->data) / parmap->num_workers)
107 + ((xbt_dynar_length(parmap->data) % parmap->num_workers) ? 1 : 0);
109 /* Each worker data segment starts in a position associated with its id*/
110 data_start = data_size * worker_id;
112 /* The end of the worker data segment must be bounded by the end of the data vector */
113 data_end = MIN(data_start + data_size, xbt_dynar_length(parmap->data));
115 DEBUG4("Worker %u: data_start=%u data_end=%u (data_size=%u)",
116 worker_id, data_start, data_end, data_size);
118 /* While the worker don't pass the end of it data segment apply the function */
119 while(data_start < data_end){
120 parmap->fun(*(void **)xbt_dynar_get_ptr(parmap->data, data_start));
124 xbt_barrier_wait(parmap->workers_done);
126 /* We are destroying the parmap */
128 xbt_barrier_wait(parmap->workers_done);
129 DEBUG1("Shutting down worker %u", worker_id);
136 static void futex_wait(int *uaddr, int val)
138 DEBUG1("Waiting on futex %d", *uaddr);
139 syscall(SYS_futex, uaddr, FUTEX_WAIT_PRIVATE, val, NULL, NULL, 0);
142 static void futex_wake(int *uaddr, int val)
144 DEBUG1("Waking futex %d", *uaddr);
145 syscall(SYS_futex, uaddr, FUTEX_WAKE_PRIVATE, val, NULL, NULL, 0);
149 /* Futex based implementation of the barrier */
150 void xbt_barrier_init(xbt_barrier_t barrier, unsigned int threads_to_wait)
152 barrier->threads_to_wait = threads_to_wait;
153 barrier->thread_count = 0;
157 void xbt_barrier_wait(xbt_barrier_t barrier)
160 unsigned int mycount = 0;
162 myflag = barrier->futex;
163 mycount = __sync_add_and_fetch(&barrier->thread_count, 1);
164 if(mycount < barrier->threads_to_wait){
165 futex_wait(&barrier->futex, myflag);
167 barrier->futex = __sync_add_and_fetch(&barrier->futex, 1);
168 barrier->thread_count = 0;
169 futex_wake(&barrier->futex, barrier->threads_to_wait);
173 void xbt_barrier_wait(xbt_barrier_t barrier)
176 unsigned int mycount = 0;
178 xbt_os_mutex_acquire(barrier->mutex);
180 barrier->thread_count++;
181 if(barrier->thread_count < barrier->threads_to_wait){
182 xbt_os_cond_wait(barrier->cond,barrier->mutex);
184 barrier->thread_count = 0;
185 xbt_os_cond_broadcast(barrier->cond);
187 xbt_os_mutex_release(barrier->mutex);
195 XBT_TEST_SUITE("parmap", "Parallel Map");
196 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(xbt_parmap_unit);
206 //INFO1("I'm job %lu", (unsigned long)arg);
209 XBT_TEST_UNIT("basic", test_parmap_basic, "Basic usage")
211 xbt_test_add0("Create the parmap");
214 xbt_dynar_t data = xbt_dynar_new(sizeof(void *), NULL);
216 /* Create the parallel map */
217 parmap = xbt_parmap_new(10);
219 for(j=0; j < 100; j++){
220 xbt_dynar_push_as(data, void *, (void *)j);
224 xbt_parmap_apply(parmap, fun, data);
226 /* Destroy the parmap */
227 xbt_parmap_destroy(parmap);
230 #endif /* SIMGRID_TEST */