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. */
7 #include <sys/syscall.h>
8 #include <linux/futex.h>
10 #include "parmap_private.h"
12 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_parmap, xbt, "parmap: parallel map");
13 XBT_LOG_NEW_SUBCATEGORY(xbt_parmap_unit, xbt_parmap, "parmap unit testing");
15 static void *_xbt_parmap_worker_main(void *parmap);
17 static void futex_wait(int *uaddr, int val);
18 static void futex_wake(int *uaddr, int val);
20 xbt_parmap_t xbt_parmap_new(unsigned int num_workers)
23 xbt_os_thread_t worker = NULL;
25 DEBUG1("Create new parmap (%u workers)", num_workers);
27 /* Initialize the thread pool data structure */
28 xbt_parmap_t parmap = xbt_new0(s_xbt_parmap_t, 1);
29 parmap->num_workers = num_workers;
30 parmap->status = PARMAP_WORK;
32 parmap->workers_ready = xbt_new0(s_xbt_barrier_t, 1);
33 xbt_barrier_init(parmap->workers_ready, num_workers + 1);
34 parmap->workers_done = xbt_new0(s_xbt_barrier_t, 1);
35 xbt_barrier_init(parmap->workers_done, num_workers + 1);
37 /* Create the pool of worker threads */
38 for(i=0; i < num_workers; i++){
39 worker = xbt_os_thread_create(NULL, _xbt_parmap_worker_main, parmap, NULL);
40 xbt_os_thread_detach(worker);
46 void xbt_parmap_destroy(xbt_parmap_t parmap)
48 DEBUG1("Destroy parmap %p", parmap);
50 parmap->status = PARMAP_DESTROY;
52 xbt_barrier_wait(parmap->workers_ready);
53 DEBUG0("Kill job sent");
54 xbt_barrier_wait(parmap->workers_done);
56 xbt_free(parmap->workers_ready);
57 xbt_free(parmap->workers_done);
61 void xbt_parmap_apply(xbt_parmap_t parmap, void_f_pvoid_t fun, xbt_dynar_t data)
63 /* Assign resources to worker threads*/
67 /* Notify workers that there is a job */
68 xbt_barrier_wait(parmap->workers_ready);
69 DEBUG0("Job dispatched, lets wait...");
70 xbt_barrier_wait(parmap->workers_done);
77 static void *_xbt_parmap_worker_main(void *arg)
79 unsigned int data_start, data_end, data_size, worker_id;
80 xbt_parmap_t parmap = (xbt_parmap_t)arg;
82 /* Fetch a worker id */
83 worker_id = __sync_fetch_and_add(&parmap->workers_max_id, 1);
85 DEBUG1("New worker thread created (%u)", worker_id);
87 /* Worker's main loop */
89 xbt_barrier_wait(parmap->workers_ready);
91 if(parmap->status == PARMAP_WORK){
92 DEBUG1("Worker %u got a job", worker_id);
94 /* Compute how much data does every worker gets */
95 data_size = (xbt_dynar_length(parmap->data) / parmap->num_workers)
96 + ((xbt_dynar_length(parmap->data) % parmap->num_workers) ? 1 : 0);
98 /* Each worker data segment starts in a position associated with its id*/
99 data_start = data_size * worker_id;
101 /* The end of the worker data segment must be bounded by the end of the data vector */
102 data_end = MIN(data_start + data_size, xbt_dynar_length(parmap->data));
104 DEBUG4("Worker %u: data_start=%u data_end=%u (data_size=%u)",
105 worker_id, data_start, data_end, data_size);
107 /* While the worker don't pass the end of it data segment apply the function */
108 while(data_start < data_end){
109 parmap->fun(*(void **)xbt_dynar_get_ptr(parmap->data, data_start));
113 xbt_barrier_wait(parmap->workers_done);
115 /* We are destroying the parmap */
117 xbt_barrier_wait(parmap->workers_done);
118 DEBUG1("Shutting down worker %u", worker_id);
124 static void futex_wait(int *uaddr, int val)
126 DEBUG1("Waiting on futex %d", *uaddr);
127 syscall(SYS_futex, uaddr, FUTEX_WAIT_PRIVATE, val, NULL, NULL, 0);
130 static void futex_wake(int *uaddr, int val)
132 DEBUG1("Waking futex %d", *uaddr);
133 syscall(SYS_futex, uaddr, FUTEX_WAKE_PRIVATE, val, NULL, NULL, 0);
136 /* Futex based implementation of the barrier */
137 void xbt_barrier_init(xbt_barrier_t barrier, unsigned int threads_to_wait)
139 barrier->threads_to_wait = threads_to_wait;
140 barrier->thread_count = 0;
143 void xbt_barrier_wait(xbt_barrier_t barrier)
146 unsigned int mycount = 0;
148 myflag = barrier->futex;
149 mycount = __sync_add_and_fetch(&barrier->thread_count, 1);
150 if(mycount < barrier->threads_to_wait){
151 futex_wait(&barrier->futex, myflag);
153 barrier->futex = __sync_add_and_fetch(&barrier->futex, 1);
154 barrier->thread_count = 0;
155 futex_wake(&barrier->futex, barrier->threads_to_wait);
163 XBT_TEST_SUITE("parmap", "Parallel Map");
164 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(xbt_parmap_unit);
174 //INFO1("I'm job %lu", (unsigned long)arg);
177 XBT_TEST_UNIT("basic", test_parmap_basic, "Basic usage")
179 xbt_test_add0("Create the parmap");
182 xbt_dynar_t data = xbt_dynar_new(sizeof(void *), NULL);
184 /* Create the parallel map */
185 parmap = xbt_parmap_new(10);
187 for(j=0; j < 100; j++){
188 xbt_dynar_push_as(data, void *, (void *)j);
192 xbt_parmap_apply(parmap, fun, data);
194 /* Destroy the parmap */
195 xbt_parmap_destroy(parmap);
198 #endif /* SIMGRID_TEST */