* under the terms of the license (GNU LGPL) which comes with this package. */
#include "gras_config.h"
#include <unistd.h>
+
#ifndef _XBT_WIN32
#include <sys/syscall.h>
#endif
#ifdef HAVE_FUTEX_H
- #include <linux/futex.h>
-#else
- #include "xbt/xbt_os_thread.h"
+#include <linux/futex.h>
#endif
-#include <errno.h>
-#include "parmap_private.h"
+
+#include "xbt/parmap.h"
+#include "xbt/log.h"
+#include "xbt/function_types.h"
+#include "xbt/dynar.h"
+#include "xbt/xbt_os_thread.h"
+#include "xbt/sysdep.h"
XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_parmap, xbt, "parmap: parallel map");
XBT_LOG_NEW_SUBCATEGORY(xbt_parmap_unit, xbt_parmap, "parmap unit testing");
-static void *_xbt_parmap_worker_main(void *parmap);
+typedef enum {
+ PARMAP_WORK = 0,
+ PARMAP_DESTROY
+} e_xbt_parmap_flag_t;
+
+static void xbt_parmap_start(xbt_parmap_t parmap);
+static void xbt_parmap_signal(xbt_parmap_t parmap);
+static void xbt_parmap_wait(xbt_parmap_t parmap);
+static void xbt_parmap_end(xbt_parmap_t parmap);
+static void *xbt_parmap_worker_main(void *parmap);
+
#ifdef HAVE_FUTEX_H
- static void futex_wait(int *uaddr, int val);
- static void futex_wake(int *uaddr, int val);
+static void futex_wait(int *uaddr, int val);
+static void futex_wake(int *uaddr, int val);
#endif
+
+/**
+ * \brief Parallel map structure
+ */
+typedef struct s_xbt_parmap {
+ e_xbt_parmap_flag_t status; /* is the parmap active or being destroyed? */
+
+ int work; /* index of the current round (1 is the first) */
+ int done; /* number of rounds already done */
+ unsigned int thread_counter; /* number of threads currently working */
+ unsigned int num_workers; /* total number of worker threads */
+ unsigned int workers_max_id; /* id of the next worker thread to create */
+ void_f_pvoid_t fun; /* function to run in parallel on each element of data */
+ xbt_dynar_t data; /* parameters to pass to fun in parallel */
+ unsigned int index; /* index of the next element of data to pick */
+} s_xbt_parmap_t;
+
+/**
+ * \brief Creates a parallel map object
+ * \param num_workers number of worker threads to create
+ * \return the parmap created
+ */
xbt_parmap_t xbt_parmap_new(unsigned int num_workers)
{
unsigned int i;
/* Initialize the thread pool data structure */
xbt_parmap_t parmap = xbt_new0(s_xbt_parmap_t, 1);
+
parmap->num_workers = num_workers;
parmap->status = PARMAP_WORK;
- parmap->workers_ready = xbt_new0(s_xbt_barrier_t, 1);
- xbt_barrier_init(parmap->workers_ready, num_workers + 1);
- parmap->workers_done = xbt_new0(s_xbt_barrier_t, 1);
- xbt_barrier_init(parmap->workers_done, num_workers + 1);
-#ifndef HAVE_FUTEX_H
- parmap->workers_ready->mutex = xbt_os_mutex_init();
- parmap->workers_ready->cond = xbt_os_cond_init();
-#endif
/* Create the pool of worker threads */
- for(i=0; i < num_workers; i++){
- worker = xbt_os_thread_create(NULL, _xbt_parmap_worker_main, parmap, NULL);
+ for (i = 0; i < num_workers; i++) {
+ worker = xbt_os_thread_create(NULL, xbt_parmap_worker_main, parmap, NULL);
xbt_os_thread_detach(worker);
}
-
+ xbt_parmap_start(parmap);
return parmap;
}
+/**
+ * \brief Destroys a parmap
+ * \param parmap the parmap to destroy
+ */
void xbt_parmap_destroy(xbt_parmap_t parmap)
-{
- XBT_DEBUG("Destroy parmap %p", parmap);
-
+{
parmap->status = PARMAP_DESTROY;
-
- xbt_barrier_wait(parmap->workers_ready);
- XBT_DEBUG("Kill job sent");
- xbt_barrier_wait(parmap->workers_done);
-#ifndef HAVE_FUTEX_H
- xbt_os_mutex_destroy(parmap->workers_ready->mutex);
- xbt_os_cond_destroy(parmap->workers_ready->cond);
-#endif
- xbt_free(parmap->workers_ready);
- xbt_free(parmap->workers_done);
+ xbt_parmap_signal(parmap);
xbt_free(parmap);
}
- void xbt_parmap_apply(xbt_parmap_t parmap, void_f_pvoid_t fun, xbt_dynar_t data)
+/**
+ * \brief Applies a list of tasks in parallel.
+ * \param parmap a parallel map object
+ * \param fun the function to call in parallel
+ * \param data each element of this dynar will be passed as an argument to fun
+ */
+void xbt_parmap_apply(xbt_parmap_t parmap, void_f_pvoid_t fun, xbt_dynar_t data)
{
- /* Assign resources to worker threads*/
+ /* Assign resources to worker threads */
parmap->fun = fun;
parmap->data = data;
-
- /* Notify workers that there is a job */
- xbt_barrier_wait(parmap->workers_ready);
- XBT_DEBUG("Job dispatched, lets wait...");
- xbt_barrier_wait(parmap->workers_done);
-
+ parmap->index = 0;
+ xbt_parmap_signal(parmap);
XBT_DEBUG("Job done");
- parmap->fun = NULL;
- parmap->data = NULL;
}
-static void *_xbt_parmap_worker_main(void *arg)
+/**
+ * \brief Returns a next task to process.
+ *
+ * Worker threads call this function to get more work.
+ *
+ * \return the next task to process, or NULL if there is no more work
+ */
+void* xbt_parmap_next(xbt_parmap_t parmap)
{
- unsigned int data_start, data_end, data_size, worker_id;
- xbt_parmap_t parmap = (xbt_parmap_t)arg;
+ unsigned int index = __sync_fetch_and_add(&parmap->index, 1);
+ if (index < xbt_dynar_length(parmap->data)) {
+ return xbt_dynar_get_as(parmap->data, index, void*);
+ }
+ return NULL;
+}
+
+/**
+ * \brief Main function of a worker thread.
+ * \param arg the parmap
+ */
+static void *xbt_parmap_worker_main(void *arg)
+{
+ unsigned int worker_id;
+ xbt_parmap_t parmap = (xbt_parmap_t) arg;
/* Fetch a worker id */
worker_id = __sync_fetch_and_add(&parmap->workers_max_id, 1);
- xbt_os_thread_set_extra_data((void *)(unsigned long)worker_id);
+ xbt_os_thread_set_extra_data((void*) (unsigned long) worker_id);
XBT_DEBUG("New worker thread created (%u)", worker_id);
-
+
/* Worker's main loop */
- while(1){
- xbt_barrier_wait(parmap->workers_ready);
+ while (1) {
+ xbt_parmap_wait(parmap);
+ if (parmap->status == PARMAP_WORK) {
- if(parmap->status == PARMAP_WORK){
XBT_DEBUG("Worker %u got a job", worker_id);
- /* Compute how much data does every worker gets */
- data_size = (xbt_dynar_length(parmap->data) / parmap->num_workers)
- + ((xbt_dynar_length(parmap->data) % parmap->num_workers) ? 1 : 0);
-
- /* Each worker data segment starts in a position associated with its id*/
- data_start = data_size * worker_id;
-
- /* The end of the worker data segment must be bounded by the end of the data vector */
- data_end = MIN(data_start + data_size, xbt_dynar_length(parmap->data));
-
- XBT_DEBUG("Worker %u: data_start=%u data_end=%u (data_size=%u)",
- worker_id, data_start, data_end, data_size);
-
- /* While the worker don't pass the end of it data segment apply the function */
- while(data_start < data_end){
- parmap->fun(*(void **)xbt_dynar_get_ptr(parmap->data, data_start));
- data_start++;
+ void* work = xbt_parmap_next(parmap);
+ if (work != NULL) {
+ parmap->fun(work);
}
- xbt_barrier_wait(parmap->workers_done);
+ XBT_DEBUG("Worker %u has finished", worker_id);
/* We are destroying the parmap */
- }else{
- xbt_barrier_wait(parmap->workers_done);
+ } else {
+ xbt_parmap_end(parmap);
XBT_DEBUG("Shutting down worker %u", worker_id);
return NULL;
}
}
#ifdef HAVE_FUTEX_H
- static void futex_wait(int *uaddr, int val)
- {
- XBT_DEBUG("Waiting on futex %d", *uaddr);
- syscall(SYS_futex, uaddr, FUTEX_WAIT_PRIVATE, val, NULL, NULL, 0);
- }
-
- static void futex_wake(int *uaddr, int val)
- {
- XBT_DEBUG("Waking futex %d", *uaddr);
- syscall(SYS_futex, uaddr, FUTEX_WAKE_PRIVATE, val, NULL, NULL, 0);
- }
+static void futex_wait(int *uaddr, int val)
+{
+ XBT_VERB("Waiting on futex %p", uaddr);
+ syscall(SYS_futex, uaddr, FUTEX_WAIT_PRIVATE, val, NULL, NULL, 0);
+}
+
+static void futex_wake(int *uaddr, int val)
+{
+ XBT_VERB("Waking futex %p", uaddr);
+ syscall(SYS_futex, uaddr, FUTEX_WAKE_PRIVATE, val, NULL, NULL, 0);
+}
#endif
-/* Futex based implementation of the barrier */
-void xbt_barrier_init(xbt_barrier_t barrier, unsigned int threads_to_wait)
+/**
+ * \brief Starts the parmap: waits for all workers to be ready and returns.
+ *
+ * This function is called by the controller thread.
+ *
+ * \param parmap a parmap
+ */
+static void xbt_parmap_start(xbt_parmap_t parmap)
{
- barrier->threads_to_wait = threads_to_wait;
- barrier->thread_count = 0;
+#ifdef HAVE_FUTEX_H
+ int myflag = parmap->done;
+ if (parmap->thread_counter < parmap->num_workers) {
+ /* wait for all workers to be ready */
+ futex_wait(&parmap->done, myflag);
+ }
+#endif
}
+/**
+ * \brief Wakes all workers and waits for them to finish the tasks.
+ *
+ * This function is called by the controller thread.
+ *
+ * \param parmap a parmap
+ */
+static void xbt_parmap_signal(xbt_parmap_t parmap)
+{
#ifdef HAVE_FUTEX_H
- void xbt_barrier_wait(xbt_barrier_t barrier)
- {
- int myflag = 0;
- unsigned int mycount = 0;
-
- myflag = barrier->futex;
- mycount = __sync_add_and_fetch(&barrier->thread_count, 1);
- if(mycount < barrier->threads_to_wait){
- futex_wait(&barrier->futex, myflag);
- }else{
- barrier->futex = __sync_add_and_fetch(&barrier->futex, 1);
- barrier->thread_count = 0;
- futex_wake(&barrier->futex, barrier->threads_to_wait);
- }
- }
-#else
- void xbt_barrier_wait(xbt_barrier_t barrier)
- {
- xbt_os_mutex_acquire(barrier->mutex);
-
- barrier->thread_count++;
- if(barrier->thread_count < barrier->threads_to_wait){
- xbt_os_cond_wait(barrier->cond,barrier->mutex);
- }else{
- barrier->thread_count = 0;
- xbt_os_cond_broadcast(barrier->cond);
- }
- xbt_os_mutex_release(barrier->mutex);
- }
+ int myflag = parmap->done;
+ parmap->thread_counter = 0;
+ parmap->work++;
+
+ /* wake all workers */
+ futex_wake(&parmap->work, parmap->num_workers);
+
+ /* wait for all of them to finish */
+ futex_wait(&parmap->done, myflag);
#endif
+}
+
+/**
+ * \brief Waits for some work to process.
+ *
+ * This function is called by each worker when it has no more work to do.
+ *
+ * \param parmap a parmap
+ */
+static void xbt_parmap_wait(xbt_parmap_t parmap)
+{
+#ifdef HAVE_FUTEX_H
+ int myflag;
+ unsigned int mycount;
+
+ myflag = parmap->work;
+ mycount = __sync_add_and_fetch(&parmap->thread_counter, 1);
+ if (mycount == parmap->num_workers) {
+ /* all workers have finished, wake the controller */
+ parmap->done++;
+ futex_wake(&parmap->done, 1);
+ }
+
+ /* wait for more work */
+ futex_wait(&parmap->work, myflag);
+#endif
+}
+
+/**
+ * \brief Ends the parmap: wakes the controller thread when all workers terminate.
+ *
+ * This function is called by all worker threads when they end.
+ *
+ * \param parmap a parmap
+ */
+static void xbt_parmap_end(xbt_parmap_t parmap)
+{
+#ifdef HAVE_FUTEX_H
+ unsigned int mycount;
+
+ mycount = __sync_add_and_fetch(&parmap->thread_counter, 1);
+ if (mycount == parmap->num_workers) {
+ /* all workers have finished, wake the controller */
+ parmap->done++;
+ futex_wake(&parmap->done, 1);
+ }
+#endif
+}
#ifdef SIMGRID_TEST
#include "xbt.h"
XBT_TEST_SUITE("parmap", "Parallel Map");
XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(xbt_parmap_unit);
-
-
xbt_parmap_t parmap;
void fun(void *arg);
{
xbt_test_add("Create the parmap");
- unsigned long i,j;
+ unsigned long i, j;
xbt_dynar_t data = xbt_dynar_new(sizeof(void *), NULL);
/* Create the parallel map */
parmap = xbt_parmap_new(10);
- for(j=0; j < 100; j++){
+ for (j = 0; j < 100; j++) {
xbt_dynar_push_as(data, void *, (void *)j);
}
- for(i=0; i < 5; i++)
+ for (i = 0; i < 5; i++) {
xbt_parmap_apply(parmap, fun, data);
+ }
/* Destroy the parmap */
xbt_parmap_destroy(parmap);
+ xbt_dynar_free(&data);
}
#endif /* SIMGRID_TEST */
