X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/d944fb42733105c9de064b3a357c4009b8280d7e..aff40f1fe3f794969ec0b80cd14cefd0d83cbe24:/src/msg/msg_task.c

diff --git a/src/msg/msg_task.c b/src/msg/msg_task.c
index a35198abf1..ec9a0d307f 100644
--- a/src/msg/msg_task.c
+++ b/src/msg/msg_task.c
@@ -5,6 +5,7 @@
  * under the terms of the license (GNU LGPL) which comes with this package. */
 
 #include "msg_private.h"
+#include "simix/smx_private.h"
 #include "xbt/sysdep.h"
 #include "xbt/log.h"
 
@@ -63,7 +64,7 @@ msg_task_t MSG_task_create(const char *name, double compute_duration,
   simdata->source = NULL;
   simdata->priority = 1.0;
   simdata->bound = 0;
-  simdata->affinity_mask = 0;
+  simdata->affinity_mask_db = xbt_dict_new_homogeneous(NULL);
   simdata->rate = -1.0;
   simdata->isused = 0;
 
@@ -285,6 +286,8 @@ msg_error_t MSG_task_destroy(msg_task_t task)
   /* parallel tasks only */
   xbt_free(task->simdata->host_list);
 
+  xbt_dict_free(&task->simdata->affinity_mask_db);
+
   /* free main structures */
   xbt_free(task->simdata);
   xbt_free(task);
@@ -466,13 +469,85 @@ void MSG_task_set_bound(msg_task_t task, double bound)
 /** \ingroup m_task_management
  * \brief Changes the CPU affinity of a computation task.
  *
+ * When pinning the given task to the first CPU core of the given host, use
+ * 0x01 for the mask value. Each bit of the mask value corresponds to each CPU
+ * core. See taskset(1) on Linux.
+ *
+ * \param task a target task
+ * \param host the host having a multi-core CPU
+ * \param mask the bit mask of a new CPU affinity setting for the task
+ *
+ *
+ * Usage:
+ * 0. Define a host with multiple cores.
+ *    <host id="PM0" power="1E8" core="2"/>
+ *
+ * 1. Pin a given task to the first CPU core of a host.
+ *   MSG_task_set_affinity(task, pm0, 0x01);
+ *
+ * 2. Pin a given task to the third CPU core of a host. Turn on the third bit of the mask.
+ *   MSG_task_set_affinity(task, pm0, 0x04); // 0x04 == 100B
+ *
+ * 3. Pin a given VM to the first CPU core of a host.
+ *   MSG_vm_set_affinity(vm, pm0, 0x01);
+ *
+ * See examples/msg/cloud/multicore.c for more information.
+ *
+ *
+ * Note:
+ * 1. The current code does not allow an affinity of a task to multiple cores.
+ * The mask value 0x03 (i.e., a given task will be executed on the first core
+ * or the second core) is not allowed. The mask value 0x01 or 0x02 works. See
+ * cpu_cas01.c for details.
+ *
+ * 2. It is recommended to first compare simulation results in both the Lazy
+ * and Full calculation modes (using --cfg=cpu/optim:Full or not). Fix
+ * cpu_cas01.c if you find wrong results in the Lazy mode.
+ *
  */
 void MSG_task_set_affinity(msg_task_t task, msg_host_t host, unsigned long mask)
 {
   xbt_assert(task, "Invalid parameter");
   xbt_assert(task->simdata, "Invalid parameter");
 
-  task->simdata->affinity_mask = mask;
-  if (task->simdata->compute)
+  if (mask == 0) {
+    /* 0 means clear */
+    {
+      /* We need remove_ext() not throwing exception. */
+      void *ret = xbt_dict_get_or_null_ext(task->simdata->affinity_mask_db, (char *) host, sizeof(msg_host_t));
+      if (ret != NULL)
+        xbt_dict_remove_ext(task->simdata->affinity_mask_db, (char *) host, sizeof(host));
+    }
+  } else
+    xbt_dict_set_ext(task->simdata->affinity_mask_db, (char *) host, sizeof(host), (void *) mask, NULL);
+
+  /* We set affinity data of this task. If the task is being executed, we
+   * actually change the affinity setting of the task. Otherwise, this change
+   * will be applied when the task is executed. */
+
+  if (!task->simdata->compute) {
+    /* task is not yet executed */
+    XBT_INFO("set affinity(0x%04lx@%s) for %s (not active now)", mask, MSG_host_get_name(host), MSG_task_get_name(task));
+    return;
+  }
+
+  {
+    smx_action_t compute = task->simdata->compute;
+    msg_host_t host_now = compute->execution.host;  // simix_private.h is necessary
+    if (host_now != host) {
+      /* task is not yet executed on this host */
+      XBT_INFO("set affinity(0x%04lx@%s) for %s (not active now)", mask, MSG_host_get_name(host), MSG_task_get_name(task));
+      return;
+    }
+
+    /* task is being executed on this host. so change the affinity now */
+    {
+      /* check it works. remove me if it works. */
+      unsigned long affinity_mask = (unsigned long) xbt_dict_get_or_null_ext(task->simdata->affinity_mask_db, (char *) host, sizeof(msg_host_t));
+      xbt_assert(affinity_mask == mask);
+    }
+
+    XBT_INFO("set affinity(0x%04lx@%s) for %s", mask, MSG_host_get_name(host), MSG_task_get_name(task));
     simcall_host_execution_set_affinity(task->simdata->compute, host, mask);
+  }
 }