X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/a889c5815b75beb11f858bab68b2314c8dc724c2..d8308c2cacc831e01b98fa8e0d593f1480c25892:/src/xbt/parmap.c

diff --git a/src/xbt/parmap.c b/src/xbt/parmap.c
index f4f92cd9f0..b6de91b177 100644
--- a/src/xbt/parmap.c
+++ b/src/xbt/parmap.c
@@ -3,144 +3,156 @@
 
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <linux/futex.h>
+#include <errno.h>
+#include "parmap_private.h"
 
-#include "threadpool_private.h"
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_parmap, xbt, "parmap: parallel map");
+XBT_LOG_NEW_SUBCATEGORY(xbt_parmap_unit, xbt_parmap, "parmap unit testing");
 
-XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_threadpool, xbt,
-                                "threadpool: pool of worker threads");
+static void *_xbt_parmap_worker_main(void *parmap);
 
-static void *_xbt_tpool_worker_main(void *tpool);
+static void futex_wait(int *uaddr, int val);
+static void futex_wake(int *uaddr, int val);
 
-unsigned long tpoolcounter = 0;  /* Debug purposes */
-
-xbt_tpool_t xbt_tpool_new(unsigned int num_workers, unsigned int max_jobs)
+xbt_parmap_t xbt_parmap_new(unsigned int num_workers)
 {
   unsigned int i;
   xbt_os_thread_t worker = NULL;
 
-  DEBUG2("Create new thread pool (%u, %u)", num_workers, max_jobs);
-
-  /* Initialize thread pool data structure */
-  xbt_tpool_t tpool = xbt_new0(s_xbt_tpool_t, 1);
-  tpool->mutex = xbt_os_mutex_init();
-  tpool->job_posted = xbt_os_cond_init();
-  tpool->job_taken = xbt_os_cond_init();
-  tpool->idle_worker = xbt_os_cond_init();
-  tpool->jobs_queue = xbt_dynar_new(sizeof(s_xbt_tpool_job_t), NULL);
-  tpool->num_workers = num_workers;
-  tpool->num_idle_workers = 0;
-  tpool->max_jobs = max_jobs;
-  
+  DEBUG1("Create new parmap (%u workers)", 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);
+
   /* Create the pool of worker threads */
   for(i=0; i < num_workers; i++){
-    worker = xbt_os_thread_create(NULL, _xbt_tpool_worker_main, tpool, NULL);
+    worker = xbt_os_thread_create(NULL, _xbt_parmap_worker_main, parmap, NULL);
     xbt_os_thread_detach(worker);
   }
   
-  return tpool;
+  return parmap;
 }
 
-void xbt_tpool_destroy(xbt_tpool_t tpool)
+void xbt_parmap_destroy(xbt_parmap_t parmap)
 { 
-  DEBUG1("Destroy thread pool %p", tpool);
+  DEBUG1("Destroy parmap %p", parmap);
 
-  /* Lock the pool, then signal every worker an wait for each to finish */
-  xbt_os_mutex_acquire(tpool->mutex);
-  tpool->flags = TPOOL_DESTROY; 
+  parmap->status = PARMAP_DESTROY;
 
-  while(tpool->num_workers){
-    DEBUG1("Still %u workers, waiting...", tpool->num_workers);
-    xbt_os_cond_signal(tpool->job_posted);
-    xbt_os_cond_wait(tpool->job_taken, tpool->mutex);
-  }
+  xbt_barrier_wait(parmap->workers_ready);
+  DEBUG0("Kill job sent");
+  xbt_barrier_wait(parmap->workers_done);
 
-  /* Destroy pool's data structures */
-  xbt_os_cond_destroy(tpool->job_posted);
-  xbt_os_cond_destroy(tpool->job_taken);
-  xbt_os_cond_destroy(tpool->idle_worker);
-  xbt_os_mutex_release(tpool->mutex);
-  xbt_os_mutex_destroy(tpool->mutex);  
-  xbt_free(tpool);
+  xbt_free(parmap->workers_ready);
+  xbt_free(parmap->workers_done);
+  xbt_free(parmap);
 }
 
-void xbt_tpool_queue_job(xbt_tpool_t tpool, void_f_pvoid_t fun, void* fun_arg)
+ void xbt_parmap_apply(xbt_parmap_t parmap, void_f_pvoid_t fun, xbt_dynar_t data)
 {
-  s_xbt_tpool_job_t job;
-  job.fun = fun;
-  job.fun_arg = fun_arg;
-
-  /* Wait until we can lock on the pool with some space on it for the job */
-  xbt_os_mutex_acquire(tpool->mutex);
-  while(xbt_dynar_length(tpool->jobs_queue) == tpool->max_jobs)
-    xbt_os_cond_wait(tpool->job_taken, tpool->mutex); 
-
-  DEBUG3("Queue job %p (%p) to thread pool %p", fun, fun_arg, tpool);
-
-  /* Push the job in the queue, signal the workers and unlock the pool */
-  xbt_dynar_push_as(tpool->jobs_queue, s_xbt_tpool_job_t, job);
-  xbt_os_cond_signal(tpool->job_posted);
-  xbt_os_mutex_release(tpool->mutex);    
-  return;
+  /* Assign resources to worker threads*/
+  parmap->fun = fun;
+  parmap->data = data;
+
+  /* Notify workers that there is a job */
+  xbt_barrier_wait(parmap->workers_ready);
+  DEBUG0("Job dispatched, lets wait...");
+  xbt_barrier_wait(parmap->workers_done);
+
+  DEBUG0("Job done");
+  parmap->fun = NULL;
+  parmap->data = NULL;
 }
 
-void xbt_tpool_wait_all(xbt_tpool_t tpool)
+static void *_xbt_parmap_worker_main(void *arg)
 {
-  DEBUG1("Wait all workers in thread pool %p", tpool);
-  xbt_os_mutex_acquire(tpool->mutex);
-
-  while(tpool->num_idle_workers < tpool->num_workers
-        || xbt_dynar_length(tpool->jobs_queue) > 0)
-    xbt_os_cond_wait(tpool->idle_worker, tpool->mutex);
+  unsigned int data_start, data_end, data_size, worker_id;
+  xbt_parmap_t parmap = (xbt_parmap_t)arg;
 
-  xbt_os_mutex_release(tpool->mutex);
-  DEBUG1("Wait all workers done in thread pool %p", tpool);
-  return;
-}
+  /* Fetch a worker id */
+  worker_id = __sync_fetch_and_add(&parmap->workers_max_id, 1);
 
-static void *_xbt_tpool_worker_main(void *arg)
-{
-  s_xbt_tpool_job_t job;
-  xbt_tpool_t tpool = (xbt_tpool_t)arg;
-
-  unsigned long i = tpoolcounter++; /* Debug purposes */
-  DEBUG1("New worker thread created (%lu)", i);
+  DEBUG1("New worker thread created (%u)", worker_id);
   
-
   /* Worker's main loop */
   while(1){
-    xbt_os_mutex_acquire(tpool->mutex);
+    xbt_barrier_wait(parmap->workers_ready);
 
-    tpool->num_idle_workers++;
-    xbt_os_cond_signal(tpool->idle_worker);
+    if(parmap->status == PARMAP_WORK){
+      DEBUG1("Worker %u got a job", worker_id);
 
-    /* If there are no jobs in the queue wait for one */
-    while(xbt_dynar_length(tpool->jobs_queue) == 0
-          && tpool->flags != TPOOL_DESTROY){
-      DEBUG1("Worker %lu waiting for a job", i);
-      xbt_os_cond_wait(tpool->job_posted, tpool->mutex);
-    }
+      /* 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;
 
-    DEBUG1("Worker %lu got a job", i);
+      /* 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));
 
-    /* If we are shutting down, signal the destroyer so it can kill the other */
-    /* workers, unlock the pool and return  */
-    if(tpool->flags == TPOOL_DESTROY){
-      DEBUG1("Shutting down worker %lu", i);
-      tpool->num_idle_workers--;
-      tpool->num_workers--;
-      xbt_os_cond_signal(tpool->job_taken);
-      xbt_os_mutex_release(tpool->mutex);
+      DEBUG4("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++;
+      }
+
+      xbt_barrier_wait(parmap->workers_done);
+
+    /* We are destroying the parmap */
+    }else{
+      xbt_barrier_wait(parmap->workers_done);
+      DEBUG1("Shutting down worker %u", worker_id);
       return NULL;
     }
+  }
+}
 
-    /* Get a job, signal the pool to inform jobs submitters and unlock it */
-    job = xbt_dynar_pop_as(tpool->jobs_queue, s_xbt_tpool_job_t);
-    xbt_os_cond_signal(tpool->job_taken);
-    tpool->num_idle_workers--;
-    xbt_os_mutex_release(tpool->mutex);
-  
-    /* Run the job and loop again ... */
-    job.fun(job.fun_arg);
+static void futex_wait(int *uaddr, int val)
+{
+  DEBUG1("Waiting on futex %d", *uaddr);
+  syscall(SYS_futex, uaddr, FUTEX_WAIT, val, NULL, NULL, 0);
+}
+
+static void futex_wake(int *uaddr, int val)
+{
+  DEBUG1("Waking futex %d", *uaddr);
+  syscall(SYS_futex, uaddr, FUTEX_WAKE, val, NULL, NULL, 0);
+}
+
+/* Futex based implementation of the barrier */
+void xbt_barrier_init(xbt_barrier_t barrier, unsigned int threads_to_wait)
+{
+  barrier->threads_to_wait = threads_to_wait;
+  barrier->thread_count = 0;
+}
+
+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);
   }
 }
 
@@ -148,36 +160,39 @@ static void *_xbt_tpool_worker_main(void *arg)
 #include "xbt.h"
 #include "xbt/ex.h"
 
-XBT_TEST_SUITE("tpool", "Thread pool");
+XBT_TEST_SUITE("parmap", "Parallel Map");
+XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(xbt_parmap_unit);
+
 
-xbt_tpool_t tpool;
 
-void job(void *arg);
+xbt_parmap_t parmap;
 
-void job (void *arg)
+void fun(void *arg);
+
+void fun(void *arg)
 {
-  xbt_test_log1("I'm job %lu", (unsigned long)arg);
+  //INFO1("I'm job %lu", (unsigned long)arg);
 }
 
-XBT_TEST_UNIT("basic", test_tpool_basic, "Basic usage")
+XBT_TEST_UNIT("basic", test_parmap_basic, "Basic usage")
 {
-  xbt_test_add0("Create thread pool");
+  xbt_test_add0("Create the parmap");
 
   unsigned long i,j;
-  /* Create thread pool */
-  tpool = xbt_tpool_new(5, 10);
+  xbt_dynar_t data = xbt_dynar_new(sizeof(void *), NULL);
 
-  for(j=0; j < 10; j++){
-    /* Queue some work */
-    for(i=0; i < 20; i++){
-      xbt_tpool_queue_job(tpool, job, (void*)i);
-    }
-    /* Wait for everyone */
-    xbt_tpool_wait_all(tpool);
+  /* Create the parallel map */
+  parmap = xbt_parmap_new(10);
+
+  for(j=0; j < 100; j++){
+    xbt_dynar_push_as(data, void *, (void *)j);
   }
 
-  /* Destroy thread pool */
-  xbt_tpool_destroy(tpool);
+  for(i=0; i < 5; i++)
+    xbt_parmap_apply(parmap, fun, data);
+
+  /* Destroy the parmap */
+  xbt_parmap_destroy(parmap);
 }
 
 #endif /* SIMGRID_TEST */