*
* \param task a target task
* \param host the host having a multi-core CPU
- * \param mask the value specifying the CPU affinity setting of the task
+ * \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)
if (mask == 0) {
/* 0 means clear */
- xbt_dict_remove_ext(task->simdata->affinity_mask_db, (char *) host, sizeof(host));
+ {
+ /* 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);
