summaryrefslogtreecommitdiff
path: root/src/threads.c
blob: 77ff7d1dd1f2cbd94c87f93ab8d55da40f7c9080 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
#include <assert.h>
#include <pthread.h>
#include <stdlib.h>

#include "fb.h"
#include "rototiller.h"
#include "threads.h"
#include "util.h"

typedef struct threads_t {
	unsigned		n_threads;

	pthread_mutex_t		idle_mutex;
	pthread_cond_t		idle_cond;
	unsigned		n_idle;

	pthread_mutex_t		frame_mutex;
	pthread_cond_t		frame_cond;
	void			(*render_fragment_func)(void *context, fb_fragment_t *fragment);
	void			*context;
	fb_fragment_t		*fragment;
	rototiller_fragmenter_t	fragmenter;

	unsigned		next_fragment;
	unsigned		frame_num;

	pthread_t		threads[];
} threads_t;


/* render fragments using the supplied render function */
static void * thread_func(void *_threads)
{
	threads_t	*threads = _threads;
	unsigned	prev_frame_num = 0;

	pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);

	for (;;) {

		/* wait for a new frame */
		pthread_mutex_lock(&threads->frame_mutex);
		pthread_cleanup_push((void (*)(void *))pthread_mutex_unlock, &threads->frame_mutex);
		while (threads->frame_num == prev_frame_num)
			pthread_cond_wait(&threads->frame_cond, &threads->frame_mutex);
		prev_frame_num = threads->frame_num;
		pthread_cleanup_pop(1);

		/* render fragments */
		for (;;) {
			unsigned	frag_num;
			fb_fragment_t	fragment;

			frag_num = __sync_fetch_and_add(&threads->next_fragment, 1);

			if (!threads->fragmenter(threads->context, threads->fragment, frag_num, &fragment))
				break;

			threads->render_fragment_func(threads->context, &fragment);
		}

		/* report as idle */
		pthread_mutex_lock(&threads->idle_mutex);
		pthread_cleanup_push((void (*)(void *))pthread_mutex_unlock, &threads->idle_mutex);
		threads->n_idle++;
		if (threads->n_idle == threads->n_threads)	/* Frame finished! Notify potential waiter. */
			pthread_cond_signal(&threads->idle_cond);
		pthread_cleanup_pop(1);
	}

	return NULL;
}


/* wait for all threads to be idle */
void threads_wait_idle(threads_t *threads)
{
	pthread_mutex_lock(&threads->idle_mutex);
	while (threads->n_idle < threads->n_threads)
		pthread_cond_wait(&threads->idle_cond, &threads->idle_mutex);
	pthread_mutex_unlock(&threads->idle_mutex);
}


/* submit a frame's fragments to the threads */
void threads_frame_submit(threads_t *threads, fb_fragment_t *fragment, rototiller_fragmenter_t fragmenter, void (*render_fragment_func)(void *context, fb_fragment_t *fragment), void *context)
{
	threads_wait_idle(threads);	/* XXX: likely non-blocking; already happens pre page flip */

	pthread_mutex_lock(&threads->frame_mutex);
	threads->fragment = fragment;
	threads->fragmenter = fragmenter;
	threads->render_fragment_func = render_fragment_func;
	threads->context = context;
	threads->frame_num++;
	threads->n_idle = threads->next_fragment = 0;
	pthread_cond_broadcast(&threads->frame_cond);
	pthread_mutex_unlock(&threads->frame_mutex);
}


/* create threads instance, a thread per cpu is created */
threads_t * threads_create(void)
{
	unsigned	i, num = get_ncpus();
	threads_t	*threads;

	threads = calloc(1, sizeof(threads_t) + sizeof(pthread_t) * num);
	if (!threads)
		return NULL;

	threads->n_idle = threads->n_threads = num;

	pthread_mutex_init(&threads->idle_mutex, NULL);
	pthread_cond_init(&threads->idle_cond, NULL);

	pthread_mutex_init(&threads->frame_mutex, NULL);
	pthread_cond_init(&threads->frame_cond, NULL);

	for (i = 0; i < num; i++)
		pthread_create(&threads->threads[i], NULL, thread_func, threads);

	return threads;
}


/* destroy a threads instance */
void threads_destroy(threads_t *threads)
{
	unsigned	i;

	for (i = 0; i < threads->n_threads; i++)
		pthread_cancel(threads->threads[i]);

	for (i = 0; i < threads->n_threads; i++)
		pthread_join(threads->threads[i], NULL);

	pthread_mutex_destroy(&threads->idle_mutex);
	pthread_cond_destroy(&threads->idle_cond);

	pthread_mutex_destroy(&threads->frame_mutex);
	pthread_cond_destroy(&threads->frame_cond);

	free(threads);
}


/* return the number of threads */
unsigned threads_num_threads(threads_t *threads)
{
	return threads->n_threads;
}
© All Rights Reserved