aboutsummaryrefslogtreecommitdiff
path: root/src/thread-pool.c
blob: b077fb9cc3d132c0bc8e3d81fa14331eab950f1c (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
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
/*
 * thread-pool.c
 *
 * A thread pool implementation
 *
 * (c) 2006-2010 Thomas White <taw@physics.org>
 *
 * Part of CrystFEL - crystallography with a FEL
 *
 */


#ifdef HAVE_CONFIG_H
#include <config.h>
#endif


#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>
#include <assert.h>

#include "utils.h"


static int use_status_labels = 0;
static pthread_key_t status_label_key;
pthread_mutex_t stderr_lock = PTHREAD_MUTEX_INITIALIZER;

struct worker_args
{
	struct task_queue_range *tqr;
	struct task_queue *tq;
	int id;
};


signed int get_status_label()
{
	int *cookie;

	if ( !use_status_labels ) {
		return -1;
	}

	cookie = pthread_getspecific(status_label_key);
	return *cookie;
}


/* ---------------------------------- Range --------------------------------- */

enum {
	TASK_READY,
	TASK_RUNNING,
	TASK_FINISHED,
};


struct task_queue_range
{
	pthread_mutex_t  lock;

	int              n_tasks;
	int             *status;
	int              n_done;

	void (*work)(int, void *);
	void *work_args;

	const char      *text;
};


static void *range_worker(void *pargsv)
{
	struct worker_args *w = pargsv;
	struct task_queue_range *q = w->tqr;
	int *cookie;

	cookie = malloc(sizeof(int));
	*cookie = w->id;
	pthread_setspecific(status_label_key, cookie);

	free(w);

	do {

		int i;
		int found = 0;
		int mytask = -1;

		/* Get a task */
		pthread_mutex_lock(&q->lock);
		for ( i=0; i<q->n_tasks; i++ ) {
			if ( q->status[i] == TASK_READY ) {
				mytask = i;
				found = 1;
				q->status[i] = TASK_RUNNING;
				break;
			}
		}
		pthread_mutex_unlock(&q->lock);

		/* No more tasks? */
		if ( !found ) break;

		q->work(mytask, q->work_args);

		/* Mark this task as done, update totals etc */
		pthread_mutex_lock(&q->lock);
		q->status[mytask] = TASK_FINISHED;
		q->n_done++;
		if ( q->text != NULL ) {
			progress_bar(q->n_done, q->n_tasks, q->text);
		}
		pthread_mutex_unlock(&q->lock);

	} while ( 1 );

	free(cookie);

	return NULL;
}


void run_thread_range(int n_tasks, int n_threads, const char *text,
                      void (*work)(int, void *), void *work_args)
{
	pthread_t *workers;
	int i;
	struct task_queue_range q;

	/* The nation of CrystFEL prides itself on having 0% unemployment. */
	if ( n_threads > n_tasks ) n_threads = n_tasks;

	pthread_key_create(&status_label_key, NULL);

	workers = malloc(n_threads * sizeof(pthread_t));

	q.status = malloc(n_tasks * sizeof(int));
	pthread_mutex_init(&q.lock, NULL);
	q.n_tasks = n_tasks;
	q.work = work;
	q.work_args = work_args;
	q.n_done = 0;
	q.text = text;

	for ( i=0; i<n_tasks; i++ ) {
		q.status[i] = TASK_READY;
	}

	/* Now it's safe to start using the status labels */
	if ( n_threads > 1 ) use_status_labels = 1;

	/* Start threads */
	for ( i=0; i<n_threads; i++ ) {

		struct worker_args *w;

		w = malloc(sizeof(struct worker_args));

		w->tqr = &q;
		w->tq = NULL;
		w->id = i;

		if ( pthread_create(&workers[i], NULL, range_worker, &w) ) {
			/* Not ERROR() here */
			fprintf(stderr, "Couldn't start thread %i\n", i);
			n_threads = i;
			break;
		}

	}

	/* Join threads */
	for ( i=0; i<n_threads; i++ ) {
		pthread_join(workers[i], NULL);
	}

	use_status_labels = 0;

	free(q.status);
	free(workers);
}


/* ---------------------------- Custom get_task() --------------------------- */

struct task_queue
{
	pthread_mutex_t  lock;

	int              n_started;
	int              n_completed;
	int              max;

	void *(*get_task)(void *);
	void (*finalise)(void *, void *);
	void *queue_args;
	void (*work)(void *, int);
};


static void *task_worker(void *pargsv)
{
	struct worker_args *w = pargsv;
	struct task_queue *q = w->tq;
	int *cookie;

	cookie = malloc(sizeof(int));
	*cookie = w->id;
	pthread_setspecific(status_label_key, cookie);

	free(w);

	do {

		void *task;
		int cookie;

		/* Get a task */
		pthread_mutex_lock(&q->lock);
		if ( (q->max) && (q->n_started >= q->max) ) {
			pthread_mutex_unlock(&q->lock);
			break;
		}
		task = q->get_task(q->queue_args);

		/* No more tasks? */
		if ( task == NULL ) {
			pthread_mutex_unlock(&q->lock);
			break;
		}

		q->n_started++;
		pthread_mutex_unlock(&q->lock);

		cookie = *(int *)pthread_getspecific(status_label_key);
		q->work(task, cookie);

		/* Update totals etc */
		pthread_mutex_lock(&q->lock);
		q->n_completed++;
		if ( q->finalise ) {
			q->finalise(q->queue_args, task);
		}
		pthread_mutex_unlock(&q->lock);

	} while ( 1 );

	free(cookie);

	return NULL;
}


int run_threads(int n_threads, void (*work)(void *, int),
                void *(*get_task)(void *), void (*final)(void *, void *),
                void *queue_args, int max)
{
	pthread_t *workers;
	int i;
	struct task_queue q;

	pthread_key_create(&status_label_key, NULL);

	workers = malloc(n_threads * sizeof(pthread_t));

	pthread_mutex_init(&q.lock, NULL);
	q.work = work;
	q.get_task = get_task;
	q.finalise = final;
	q.queue_args = queue_args;
	q.n_started = 0;
	q.n_completed = 0;
	q.max = max;

	/* Now it's safe to start using the status labels */
	if ( n_threads > 1 ) use_status_labels = 1;

	/* Start threads */
	for ( i=0; i<n_threads; i++ ) {

		struct worker_args *w;

		w = malloc(sizeof(struct worker_args));

		w->tq = &q;
		w->tqr = NULL;
		w->id = i;

		if ( pthread_create(&workers[i], NULL, task_worker, w) ) {
			/* Not ERROR() here */
			fprintf(stderr, "Couldn't start thread %i\n", i);
			n_threads = i;
			break;
		}

	}

	/* Join threads */
	for ( i=0; i<n_threads; i++ ) {
		pthread_join(workers[i], NULL);
	}

	use_status_labels = 0;

	free(workers);

	return q.n_completed;
}