--- /dev/null
+/* worker thread pool based on POSIX threads
+ * author: John Tsiombikas <nuclear@member.fsf.org>
+ * This code is public domain.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <pthread.h>
+#include "tpool.h"
+
+#if defined(__APPLE__) && defined(__MACH__)
+# ifndef __unix__
+# define __unix__ 1
+# endif /* unix */
+# ifndef __bsd__
+# define __bsd__ 1
+# endif /* bsd */
+#endif /* apple */
+
+#if defined(unix) || defined(__unix__)
+#include <unistd.h>
+#include <sys/time.h>
+
+# ifdef __bsd__
+# include <sys/sysctl.h>
+# endif
+#endif
+
+#if defined(WIN32) || defined(__WIN32__)
+#include <windows.h>
+#endif
+
+
+struct work_item {
+ void *data;
+ tpool_callback work, done;
+ struct work_item *next;
+};
+
+struct thread_data {
+ int id;
+ struct thread_pool *pool;
+};
+
+struct thread_pool {
+ pthread_t *threads;
+ struct thread_data *tdata;
+ int num_threads;
+ pthread_key_t idkey;
+
+ int qsize;
+ struct work_item *workq, *workq_tail;
+ pthread_mutex_t workq_mutex;
+ pthread_cond_t workq_condvar;
+
+ int nactive; /* number of active workers (not sleeping) */
+
+ pthread_cond_t done_condvar;
+
+ int should_quit;
+ int in_batch;
+
+ int nref; /* reference count */
+
+#if defined(WIN32) || defined(__WIN32__)
+ HANDLE wait_event;
+#else
+ int wait_pipe[2];
+#endif
+};
+
+static void *thread_func(void *args);
+static void send_done_event(struct thread_pool *tpool);
+
+static struct work_item *alloc_work_item(void);
+static void free_work_item(struct work_item *w);
+
+
+struct thread_pool *tpool_create(int num_threads)
+{
+ int i;
+ struct thread_pool *tpool;
+
+ if(!(tpool = calloc(1, sizeof *tpool))) {
+ return 0;
+ }
+ pthread_mutex_init(&tpool->workq_mutex, 0);
+ pthread_cond_init(&tpool->workq_condvar, 0);
+ pthread_cond_init(&tpool->done_condvar, 0);
+ pthread_key_create(&tpool->idkey, 0);
+
+ pthread_setspecific(tpool->idkey, (void*)0xffffffff);
+
+#if !defined(WIN32) && !defined(__WIN32__)
+ tpool->wait_pipe[0] = tpool->wait_pipe[1] = -1;
+#endif
+
+ if(num_threads <= 0) {
+ num_threads = tpool_num_processors();
+ }
+ tpool->num_threads = num_threads;
+
+ if(!(tpool->threads = calloc(num_threads, sizeof *tpool->threads))) {
+ free(tpool);
+ return 0;
+ }
+ if(!(tpool->tdata = malloc(num_threads * sizeof *tpool->tdata))) {
+ free(tpool->threads);
+ free(tpool);
+ return 0;
+ }
+
+ for(i=0; i<num_threads; i++) {
+ tpool->tdata[i].id = i;
+ tpool->tdata[i].pool = tpool;
+
+ if(pthread_create(tpool->threads + i, 0, thread_func, tpool->tdata + i) == -1) {
+ /*tpool->threads[i] = 0;*/
+ tpool_destroy(tpool);
+ return 0;
+ }
+ }
+ return tpool;
+}
+
+void tpool_destroy(struct thread_pool *tpool)
+{
+ int i;
+ if(!tpool) return;
+
+ tpool_clear(tpool);
+ tpool->should_quit = 1;
+
+ pthread_cond_broadcast(&tpool->workq_condvar);
+
+ if(tpool->threads) {
+ for(i=0; i<tpool->num_threads; i++) {
+ pthread_join(tpool->threads[i], 0);
+ }
+ putchar('\n');
+ free(tpool->threads);
+ }
+ free(tpool->tdata);
+
+ /* also wake up anyone waiting on the wait* calls */
+ tpool->nactive = 0;
+ pthread_cond_broadcast(&tpool->done_condvar);
+ send_done_event(tpool);
+
+ pthread_mutex_destroy(&tpool->workq_mutex);
+ pthread_cond_destroy(&tpool->workq_condvar);
+ pthread_cond_destroy(&tpool->done_condvar);
+ pthread_key_delete(tpool->idkey);
+
+#if defined(WIN32) || defined(__WIN32__)
+ if(tpool->wait_event) {
+ CloseHandle(tpool->wait_event);
+ }
+#else
+ if(tpool->wait_pipe[0] >= 0) {
+ close(tpool->wait_pipe[0]);
+ close(tpool->wait_pipe[1]);
+ }
+#endif
+}
+
+int tpool_addref(struct thread_pool *tpool)
+{
+ return ++tpool->nref;
+}
+
+int tpool_release(struct thread_pool *tpool)
+{
+ if(--tpool->nref <= 0) {
+ tpool_destroy(tpool);
+ return 0;
+ }
+ return tpool->nref;
+}
+
+void tpool_begin_batch(struct thread_pool *tpool)
+{
+ tpool->in_batch = 1;
+}
+
+void tpool_end_batch(struct thread_pool *tpool)
+{
+ tpool->in_batch = 0;
+ pthread_cond_broadcast(&tpool->workq_condvar);
+}
+
+int tpool_enqueue(struct thread_pool *tpool, void *data,
+ tpool_callback work_func, tpool_callback done_func)
+{
+ struct work_item *job;
+
+ if(!(job = alloc_work_item())) {
+ return -1;
+ }
+ job->work = work_func;
+ job->done = done_func;
+ job->data = data;
+ job->next = 0;
+
+ pthread_mutex_lock(&tpool->workq_mutex);
+ if(tpool->workq) {
+ tpool->workq_tail->next = job;
+ tpool->workq_tail = job;
+ } else {
+ tpool->workq = tpool->workq_tail = job;
+ }
+ ++tpool->qsize;
+ pthread_mutex_unlock(&tpool->workq_mutex);
+
+ if(!tpool->in_batch) {
+ pthread_cond_broadcast(&tpool->workq_condvar);
+ }
+ return 0;
+}
+
+void tpool_clear(struct thread_pool *tpool)
+{
+ pthread_mutex_lock(&tpool->workq_mutex);
+ while(tpool->workq) {
+ void *tmp = tpool->workq;
+ tpool->workq = tpool->workq->next;
+ free(tmp);
+ }
+ tpool->workq = tpool->workq_tail = 0;
+ tpool->qsize = 0;
+ pthread_mutex_unlock(&tpool->workq_mutex);
+}
+
+int tpool_queued_jobs(struct thread_pool *tpool)
+{
+ int res;
+ pthread_mutex_lock(&tpool->workq_mutex);
+ res = tpool->qsize;
+ pthread_mutex_unlock(&tpool->workq_mutex);
+ return res;
+}
+
+int tpool_active_jobs(struct thread_pool *tpool)
+{
+ int res;
+ pthread_mutex_lock(&tpool->workq_mutex);
+ res = tpool->nactive;
+ pthread_mutex_unlock(&tpool->workq_mutex);
+ return res;
+}
+
+int tpool_pending_jobs(struct thread_pool *tpool)
+{
+ int res;
+ pthread_mutex_lock(&tpool->workq_mutex);
+ res = tpool->qsize + tpool->nactive;
+ pthread_mutex_unlock(&tpool->workq_mutex);
+ return res;
+}
+
+void tpool_wait(struct thread_pool *tpool)
+{
+ pthread_mutex_lock(&tpool->workq_mutex);
+ while(tpool->nactive || tpool->qsize) {
+ pthread_cond_wait(&tpool->done_condvar, &tpool->workq_mutex);
+ }
+ pthread_mutex_unlock(&tpool->workq_mutex);
+}
+
+void tpool_wait_pending(struct thread_pool *tpool, int pending_target)
+{
+ pthread_mutex_lock(&tpool->workq_mutex);
+ while(tpool->qsize + tpool->nactive > pending_target) {
+ pthread_cond_wait(&tpool->done_condvar, &tpool->workq_mutex);
+ }
+ pthread_mutex_unlock(&tpool->workq_mutex);
+}
+
+#if defined(WIN32) || defined(__WIN32__)
+long tpool_timedwait(struct thread_pool *tpool, long timeout)
+{
+ fprintf(stderr, "tpool_timedwait currently unimplemented on windows\n");
+ abort();
+ return 0;
+}
+
+/* TODO: actually does this work with MinGW ? */
+int tpool_get_wait_fd(struct thread_pool *tpool)
+{
+ static int once;
+ if(!once) {
+ once = 1;
+ fprintf(stderr, "warning: tpool_get_wait_fd call on Windows does nothing\n");
+ }
+ return 0;
+}
+
+void *tpool_get_wait_handle(struct thread_pool *tpool)
+{
+ if(!tpool->wait_event) {
+ if(!(tpool->wait_event = CreateEvent(0, 0, 0, 0))) {
+ return 0;
+ }
+ }
+ return tpool->wait_event;
+}
+
+static void send_done_event(struct thread_pool *tpool)
+{
+ if(tpool->wait_event) {
+ SetEvent(tpool->wait_event);
+ }
+}
+
+#else /* UNIX */
+
+long tpool_timedwait(struct thread_pool *tpool, long timeout)
+{
+ struct timespec tout_ts;
+ struct timeval tv0, tv;
+ gettimeofday(&tv0, 0);
+
+ long sec = timeout / 1000;
+ tout_ts.tv_nsec = tv0.tv_usec * 1000 + (timeout % 1000) * 1000000;
+ tout_ts.tv_sec = tv0.tv_sec + sec;
+
+ pthread_mutex_lock(&tpool->workq_mutex);
+ while(tpool->nactive || tpool->qsize) {
+ if(pthread_cond_timedwait(&tpool->done_condvar,
+ &tpool->workq_mutex, &tout_ts) == ETIMEDOUT) {
+ break;
+ }
+ }
+ pthread_mutex_unlock(&tpool->workq_mutex);
+
+ gettimeofday(&tv, 0);
+ return (tv.tv_sec - tv0.tv_sec) * 1000 + (tv.tv_usec - tv0.tv_usec) / 1000;
+}
+
+int tpool_get_wait_fd(struct thread_pool *tpool)
+{
+ if(tpool->wait_pipe[0] < 0) {
+ if(pipe(tpool->wait_pipe) == -1) {
+ return -1;
+ }
+ }
+ return tpool->wait_pipe[0];
+}
+
+void *tpool_get_wait_handle(struct thread_pool *tpool)
+{
+ static int once;
+ if(!once) {
+ once = 1;
+ fprintf(stderr, "warning: tpool_get_wait_handle call on UNIX does nothing\n");
+ }
+ return 0;
+}
+
+static void send_done_event(struct thread_pool *tpool)
+{
+ if(tpool->wait_pipe[1] >= 0) {
+ write(tpool->wait_pipe[1], tpool, 1);
+ }
+}
+#endif /* WIN32/UNIX */
+
+static void *thread_func(void *args)
+{
+ struct thread_data *tdata = args;
+ struct thread_pool *tpool = tdata->pool;
+
+ pthread_setspecific(tpool->idkey, (void*)(intptr_t)tdata->id);
+
+ pthread_mutex_lock(&tpool->workq_mutex);
+ while(!tpool->should_quit) {
+ if(!tpool->workq) {
+ pthread_cond_wait(&tpool->workq_condvar, &tpool->workq_mutex);
+ if(tpool->should_quit) break;
+ }
+
+ while(!tpool->should_quit && tpool->workq) {
+ /* grab the first job */
+ struct work_item *job = tpool->workq;
+ tpool->workq = tpool->workq->next;
+ if(!tpool->workq)
+ tpool->workq_tail = 0;
+ ++tpool->nactive;
+ --tpool->qsize;
+ pthread_mutex_unlock(&tpool->workq_mutex);
+
+ /* do the job */
+ job->work(job->data);
+ if(job->done) {
+ job->done(job->data);
+ }
+ free_work_item(job);
+
+ pthread_mutex_lock(&tpool->workq_mutex);
+ /* notify everyone interested that we're done with this job */
+ pthread_cond_broadcast(&tpool->done_condvar);
+ send_done_event(tpool);
+ --tpool->nactive;
+ }
+ }
+ pthread_mutex_unlock(&tpool->workq_mutex);
+
+ return 0;
+}
+
+
+int tpool_thread_id(struct thread_pool *tpool)
+{
+ int id = (intptr_t)pthread_getspecific(tpool->idkey);
+ if(id >= tpool->num_threads) {
+ return -1;
+ }
+ return id;
+}
+
+
+/* The following highly platform-specific code detects the number
+ * of processors available in the system. It's used by the thread pool
+ * to autodetect how many threads to spawn.
+ * Currently works on: Linux, BSD, Darwin, and Windows.
+ */
+int tpool_num_processors(void)
+{
+#if defined(unix) || defined(__unix__)
+# if defined(__bsd__)
+ /* BSD systems provide the num.processors through sysctl */
+ int num, mib[] = {CTL_HW, HW_NCPU};
+ size_t len = sizeof num;
+
+ sysctl(mib, 2, &num, &len, 0, 0);
+ return num;
+
+# elif defined(__sgi)
+ /* SGI IRIX flavour of the _SC_NPROC_ONLN sysconf */
+ return sysconf(_SC_NPROC_ONLN);
+# else
+ /* Linux (and others?) have the _SC_NPROCESSORS_ONLN sysconf */
+ return sysconf(_SC_NPROCESSORS_ONLN);
+# endif /* bsd/sgi/other */
+
+#elif defined(WIN32) || defined(__WIN32__)
+ /* under windows we need to call GetSystemInfo */
+ SYSTEM_INFO info;
+ GetSystemInfo(&info);
+ return info.dwNumberOfProcessors;
+#endif
+}
+
+#define MAX_WPOOL_SIZE 64
+static pthread_mutex_t wpool_lock = PTHREAD_MUTEX_INITIALIZER;
+static struct work_item *wpool;
+static int wpool_size;
+
+/* work item allocator */
+static struct work_item *alloc_work_item(void)
+{
+ struct work_item *w;
+
+ pthread_mutex_lock(&wpool_lock);
+ if(!wpool) {
+ pthread_mutex_unlock(&wpool_lock);
+ return malloc(sizeof(struct work_item));
+ }
+
+ w = wpool;
+ wpool = wpool->next;
+ --wpool_size;
+ pthread_mutex_unlock(&wpool_lock);
+ return w;
+}
+
+static void free_work_item(struct work_item *w)
+{
+ pthread_mutex_lock(&wpool_lock);
+ if(wpool_size >= MAX_WPOOL_SIZE) {
+ free(w);
+ } else {
+ w->next = wpool;
+ wpool = w;
+ ++wpool_size;
+ }
+ pthread_mutex_unlock(&wpool_lock);
+}
--- /dev/null
+/* worker thread pool based on POSIX threads
+ * author: John Tsiombikas <nuclear@member.fsf.org>
+ * This code is public domain.
+ */
+#ifndef THREADPOOL_H_
+#define THREADPOOL_H_
+
+struct thread_pool;
+
+/* type of the function accepted as work or completion callback */
+typedef void (*tpool_callback)(void*);
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* if num_threads == 0, auto-detect how many threads to spawn */
+struct thread_pool *tpool_create(int num_threads);
+void tpool_destroy(struct thread_pool *tpool);
+
+/* optional reference counting interface for thread pool sharing */
+int tpool_addref(struct thread_pool *tpool);
+int tpool_release(struct thread_pool *tpool); /* will tpool_destroy on nref 0 */
+
+/* if begin_batch is called before an enqueue, the worker threads will not be
+ * signalled to start working until end_batch is called.
+ */
+void tpool_begin_batch(struct thread_pool *tpool);
+void tpool_end_batch(struct thread_pool *tpool);
+
+/* if enqueue is called without calling begin_batch first, it will immediately
+ * wake up the worker threads to start working on the enqueued item
+ */
+int tpool_enqueue(struct thread_pool *tpool, void *data,
+ tpool_callback work_func, tpool_callback done_func);
+/* clear the work queue. does not cancel any currently running jobs */
+void tpool_clear(struct thread_pool *tpool);
+
+/* returns the number of queued work items */
+int tpool_queued_jobs(struct thread_pool *tpool);
+/* returns the number of active (working) threads */
+int tpool_active_jobs(struct thread_pool *tpool);
+/* returns the number of pending jobs, both in queue and active */
+int tpool_pending_jobs(struct thread_pool *tpool);
+
+/* wait for all pending jobs to be completed */
+void tpool_wait(struct thread_pool *tpool);
+/* wait until the pending jobs are down to the target specified
+ * for example, to wait until a single job has been completed:
+ * tpool_wait_pending(tpool, tpool_pending_jobs(tpool) - 1);
+ * this interface is slightly awkward to avoid race conditions. */
+void tpool_wait_pending(struct thread_pool *tpool, int pending_target);
+/* wait for all pending jobs to be completed for up to "timeout" milliseconds */
+long tpool_timedwait(struct thread_pool *tpool, long timeout);
+
+/* return a file descriptor which can be used to wait for pending job
+ * completion events. A single char is written every time a job completes.
+ * You should empty the pipe every time you receive such an event.
+ *
+ * This is a UNIX-specific call. On windows it does nothing.
+ */
+int tpool_get_wait_fd(struct thread_pool *tpool);
+
+/* return an auto-resetting Event HANDLE which can be used to wait for
+ * pending job completion events.
+ *
+ * This is a Win32-specific call. On UNIX it does nothing.
+ */
+void *tpool_get_wait_handle(struct thread_pool *tpool);
+
+/* When called by a work/done callback, it returns the thread number executing
+ * it. From the main thread it returns -1.
+ */
+int tpool_thread_id(struct thread_pool *tpool);
+
+
+/* returns the number of processors on the system.
+ * individual cores in multi-core processors are counted as processors.
+ */
+int tpool_num_processors(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* THREADPOOL_H_ */
projects / cyberay / commitdiff