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
|
#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;
rototiller_frame_t *frame;
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;
for (;;) {
unsigned frag_idx;
/* wait for a new frame */
pthread_mutex_lock(&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_mutex_unlock(&threads->frame_mutex);
/* render fragments */
for (frag_idx = __sync_fetch_and_add(&threads->next_fragment, 1);
frag_idx < threads->frame->n_fragments;
frag_idx = __sync_fetch_and_add(&threads->next_fragment, 1)) {
threads->render_fragment_func(threads->context, &threads->frame->fragments[frag_idx]);
}
/* report as idle */
pthread_mutex_lock(&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_mutex_unlock(&threads->idle_mutex);
}
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, rototiller_frame_t *frame, 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->frame = frame;
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;
}
|
