X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/ee52e8901be69e4287c5ab242d0e9ca10df45bf9..c4ae2de12a09603490cc5b40cf9e4729d205bc25:/src/xbt/parmap.c diff --git a/src/xbt/parmap.c b/src/xbt/parmap.c index 25cf6ff46c..b9db0756a4 100644 --- a/src/xbt/parmap.c +++ b/src/xbt/parmap.c @@ -5,26 +5,62 @@ * under the terms of the license (GNU LGPL) which comes with this package. */ #include "gras_config.h" #include + #ifndef _XBT_WIN32 #include #endif #ifdef HAVE_FUTEX_H - #include -#else - #include "xbt/xbt_os_thread.h" +#include #endif -#include -#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; @@ -34,160 +70,195 @@ xbt_parmap_t xbt_parmap_new(unsigned int num_workers) /* 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; - - /* 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_DEBUG("New worker thread created (%u)", worker_id); - - /* Worker's main loop */ - while(1){ - xbt_barrier_wait(parmap->workers_ready); - - if(parmap->status == PARMAP_WORK){ - XBT_DEBUG("Worker %u got a job", worker_id); + 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; +} - /* 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); +/** + * \brief Main function of a worker thread. + * \param arg the parmap + */ +static void *xbt_parmap_worker_main(void *arg) +{ + xbt_parmap_t parmap = (xbt_parmap_t) arg; - /* Each worker data segment starts in a position associated with its id*/ - data_start = data_size * worker_id; + XBT_DEBUG("New worker thread created"); - /* 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)); + /* Worker's main loop */ + while (1) { + xbt_parmap_wait(parmap); + if (parmap->status == PARMAP_WORK) { - XBT_DEBUG("Worker %u: data_start=%u data_end=%u (data_size=%u)", - worker_id, data_start, data_end, data_size); + XBT_DEBUG("Worker got a job"); - /* 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 has finished"); /* We are destroying the parmap */ - }else{ - xbt_barrier_wait(parmap->workers_done); - XBT_DEBUG("Shutting down worker %u", worker_id); + } else { + xbt_parmap_end(parmap); + XBT_DEBUG("Shutting down worker"); 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 + +/** + * \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) +{ +#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 + 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 +} -/* Futex based implementation of the barrier */ -void xbt_barrier_init(xbt_barrier_t barrier, unsigned int threads_to_wait) +/** + * \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) { - barrier->threads_to_wait = threads_to_wait; - barrier->thread_count = 0; +#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 - 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); - } + 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" @@ -196,8 +267,6 @@ void xbt_barrier_init(xbt_barrier_t barrier, unsigned int threads_to_wait) XBT_TEST_SUITE("parmap", "Parallel Map"); XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(xbt_parmap_unit); - - xbt_parmap_t parmap; void fun(void *arg); @@ -211,18 +280,19 @@ XBT_TEST_UNIT("basic", test_parmap_basic, "Basic usage") { 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);