nuclear@6: #include <stdio.h>
nuclear@6: #include <stdlib.h>
nuclear@6: #include <string.h>
nuclear@6: #include <pthread.h>
nuclear@6: #include "threadpool.h"
nuclear@6: 
nuclear@6: struct work_item {
nuclear@6: 	void *data;
nuclear@6: 	struct work_item *next;
nuclear@6: };
nuclear@6: 
nuclear@6: struct thread_pool {
nuclear@6: 	pthread_t *workers;
nuclear@6: 	int num_workers;
nuclear@6: 
nuclear@6: 	pthread_mutex_t work_lock;
nuclear@6: 	pthread_cond_t work_cond;
nuclear@6: 
nuclear@6: 	tpool_work_func work_func;
nuclear@6: 	void *cls;
nuclear@6: 
nuclear@6: 	struct work_item *work_list, *work_list_tail;
nuclear@6: 	int work_count;
nuclear@6: };
nuclear@6: 
nuclear@6: 
nuclear@6: static void *thread_func(void *tp);
nuclear@6: static struct work_item *alloc_node(void);
nuclear@6: static void free_node(struct work_item *node);
nuclear@6: static int get_processor_count(void);
nuclear@6: 
nuclear@6: 
nuclear@6: 
nuclear@6: int tpool_init(struct thread_pool *tpool, int num_threads)
nuclear@6: {
nuclear@6: 	int i;
nuclear@6: 
nuclear@6: 	memset(tpool, 0, sizeof *tpool);
nuclear@6: 
nuclear@6: 	if(num_threads <= 0) {
nuclear@6: 		num_threads = get_processor_count();
nuclear@6: 	}
nuclear@6: 	tpool->num_workers = num_threads;
nuclear@6: 
nuclear@6: 	printf("initializing thread pool with %d worker threads\n", num_threads);
nuclear@6: 
nuclear@6: 	for(i=0; i<num_threads; i++) {
nuclear@6: 		if(pthread_create(tpool->workers + i, 0, thread_func, tpool) == -1) {
nuclear@6: 			fprintf(stderr, "%s: failed to create thread %d\n", __FUNCTION__, i);
nuclear@6: 			tpool_destroy(tpool);
nuclear@6: 			return -1;
nuclear@6: 		}
nuclear@6: 	}
nuclear@6: 
nuclear@6: 	pthread_mutex_init(&tpool->work_lock, 0);
nuclear@6: 	pthread_cond_init(&tpool->work_cond, 0);
nuclear@6: 	return 0;
nuclear@6: }
nuclear@6: 
nuclear@6: void tpool_destroy(struct thread_pool *tpool)
nuclear@6: {
nuclear@6: 	int i;
nuclear@6: 	for(i=0; i<tpool->num_workers; i++) {
nuclear@6: 		void *ret;
nuclear@6: 		pthread_join(tpool->workers[i], &ret);
nuclear@6: 	}
nuclear@6: 
nuclear@6: 	pthread_mutex_destroy(&tpool->work_lock);
nuclear@6: 	pthread_cond_destroy(&tpool->work_cond);
nuclear@6: }
nuclear@6: 
nuclear@6: void tpool_set_work_func(struct thread_pool *tpool, tpool_work_func func, void *cls)
nuclear@6: {
nuclear@6: 	tpool->work_func = func;
nuclear@6: 	tpool->cls = cls;
nuclear@6: }
nuclear@6: 
nuclear@6: int tpool_add_work(struct thread_pool *tpool, void *data)
nuclear@6: {
nuclear@6: 	struct work_item *node;
nuclear@6: 
nuclear@6: 	if(!(node = alloc_node())) {
nuclear@6: 		fprintf(stderr, "%s: failed to allocate new work item node\n", __FUNCTION__);
nuclear@6: 		return -1;
nuclear@6: 	}
nuclear@6: 	node->data = data;
nuclear@6: 	node->next = 0;
nuclear@6: 
nuclear@6: 	pthread_mutex_lock(&tpool->work_lock);
nuclear@6: 
nuclear@6: 	if(!tpool->work_list) {
nuclear@6: 		tpool->work_list = tpool->work_list_tail = node;
nuclear@6: 	} else {
nuclear@6: 		tpool->work_list_tail->next = node;
nuclear@6: 		tpool->work_list_tail = node;
nuclear@6: 	}
nuclear@6: 
nuclear@6: 	pthread_mutex_unlock(&tpool->work_lock);
nuclear@6: 	return 0;
nuclear@6: }
nuclear@6: 
nuclear@6: 
nuclear@6: static void *thread_func(void *tp)
nuclear@6: {
nuclear@6: 	struct work_item *job;
nuclear@6: 	struct thread_pool *tpool = tp;
nuclear@6: 
nuclear@6: 	pthread_mutex_lock(&tpool->work_lock);
nuclear@6: 	for(;;) {
nuclear@6: 		/* while there aren't any work items to do go to sleep on the condvar */
nuclear@6: 		pthread_cond_wait(&tpool->work_cond, &tpool->work_lock);
nuclear@6: 		if(!tpool->work_list) {
nuclear@6: 			continue;	/* spurious wakeup, go back to sleep */
nuclear@6: 		}
nuclear@6: 
nuclear@6: 		job = tpool->work_list;
nuclear@6: 		tpool->work_list = tpool->work_list->next;
nuclear@6: 
nuclear@6: 		tpool->work_func(job->data, tpool->cls);
nuclear@6: 	}
nuclear@6: 	pthread_mutex_unlock(&tpool->work_lock);
nuclear@6: 	return 0;
nuclear@6: }
nuclear@6: 
nuclear@6: /* TODO: custom allocator */
nuclear@6: static struct work_item *alloc_node(void)
nuclear@6: {
nuclear@6: 	return malloc(sizeof(struct work_item));
nuclear@6: }
nuclear@6: 
nuclear@6: static void free_node(struct work_item *node)
nuclear@6: {
nuclear@6: 	free(node);
nuclear@6: }
nuclear@6: 
nuclear@6: /* The following highly platform-specific code detects the number
nuclear@6:  * of processors available in the system. It's used by the thread pool
nuclear@6:  * to autodetect how many threads to spawn.
nuclear@6:  * Currently works on: Linux, BSD, Darwin, and Windows.
nuclear@6:  */
nuclear@6: 
nuclear@6: #if defined(__APPLE__) && defined(__MACH__)
nuclear@6: # ifndef __unix__
nuclear@6: #  define __unix__	1
nuclear@6: # endif	/* unix */
nuclear@6: # ifndef __bsd__
nuclear@6: #  define __bsd__	1
nuclear@6: # endif	/* bsd */
nuclear@6: #endif	/* apple */
nuclear@6: 
nuclear@6: #if defined(unix) || defined(__unix__)
nuclear@6: #include <unistd.h>
nuclear@6: 
nuclear@6: # ifdef __bsd__
nuclear@6: #  include <sys/sysctl.h>
nuclear@6: # endif
nuclear@6: #endif
nuclear@6: 
nuclear@6: #if defined(WIN32) || defined(__WIN32__)
nuclear@6: #include <windows.h>
nuclear@6: #endif
nuclear@6: 
nuclear@6: 
nuclear@6: static int get_processor_count(void)
nuclear@6: {
nuclear@6: #if defined(unix) || defined(__unix__)
nuclear@6: # if defined(__bsd__)
nuclear@6: 	/* BSD systems provide the num.processors through sysctl */
nuclear@6: 	int num, mib[] = {CTL_HW, HW_NCPU};
nuclear@6: 	size_t len = sizeof num;
nuclear@6: 
nuclear@6: 	sysctl(mib, 2, &num, &len, 0, 0);
nuclear@6: 	return num;
nuclear@6: 
nuclear@6: # elif defined(__sgi)
nuclear@6: 	/* SGI IRIX flavour of the _SC_NPROC_ONLN sysconf */
nuclear@6: 	return sysconf(_SC_NPROC_ONLN);
nuclear@6: # else
nuclear@6: 	/* Linux (and others?) have the _SC_NPROCESSORS_ONLN sysconf */
nuclear@6: 	return sysconf(_SC_NPROCESSORS_ONLN);
nuclear@6: # endif	/* bsd/sgi/other */
nuclear@6: 
nuclear@6: #elif defined(WIN32) || defined(__WIN32__)
nuclear@6: 	/* under windows we need to call GetSystemInfo */
nuclear@6: 	SYSTEM_INFO info;
nuclear@6: 	GetSystemInfo(&info);
nuclear@6: 	return info.dwNumberOfProcessors;
nuclear@6: #endif
nuclear@6: }