Merge branch 'skinny_task' into 'master'

Pack the task types and re-arrange the task structure to go from 80 bytes to 64 bytes.



See merge request !238

src/scheduler.c

@@ -764,8 +764,9 @@ void scheduler_set_unlocks(struct scheduler *s) {
     t->unlock_tasks = &s->unlocks[offsets[k]];
   }
 
+#ifdef SWIFT_DEBUG_CHECKS
   /* Verify that there are no duplicate unlocks. */
-  /* for (int k = 0; k < s->nr_tasks; k++) {
+  for (int k = 0; k < s->nr_tasks; k++) {
     struct task *t = &s->tasks[k];
     for (int i = 0; i < t->nr_unlock_tasks; i++) {
       for (int j = i + 1; j < t->nr_unlock_tasks; j++) {
@@ -773,7 +774,8 @@ void scheduler_set_unlocks(struct scheduler *s) {
           error("duplicate unlock!");
       }
     }
-  } */
+  }
+#endif
 
   /* Clean up. */
   free(counts);
@@ -862,9 +864,11 @@ void scheduler_reset(struct scheduler *s, int size) {
     if (s->tasks_ind != NULL) free(s->tasks_ind);
 
     /* Allocate the new lists. */
-    if ((s->tasks = (struct task *)malloc(sizeof(struct task) * size)) ==
-            NULL ||
-        (s->tasks_ind = (int *)malloc(sizeof(int) * size)) == NULL)
+    if (posix_memalign((void *)&s->tasks, task_align,
+                       size * sizeof(struct task)) != 0)
+      error("Failed to allocate task array.");
+
+    if ((s->tasks_ind = (int *)malloc(sizeof(int) * size)) == NULL)
       error("Failed to allocate task lists.");
   }
 

src/task.h

@@ -29,6 +29,8 @@
 #include "cell.h"
 #include "cycle.h"
 
+#define task_align 128
+
 /**
  * @brief The different task types.
  */
@@ -52,7 +54,7 @@ enum task_types {
   task_type_grav_up,
   task_type_grav_external,
   task_type_count
-};
+} __attribute__((packed));
 
 /**
  * @brief The different task sub-types (for pairs, selfs and sub-tasks).
@@ -65,7 +67,7 @@ enum task_subtypes {
   task_subtype_grav,
   task_subtype_tend,
   task_subtype_count
-};
+} __attribute__((packed));
 
 /**
  * @brief The type of particles/objects this task acts upon in a given cell.
@@ -94,48 +96,48 @@ extern const char *subtaskID_names[];
  */
 struct task {
 
-  /*! Type of the task */
-  enum task_types type;
+  /*! Pointers to the cells this task acts upon */
+  struct cell *ci, *cj;
 
-  /*! Sub-type of the task (for the tasks that have one */
-  enum task_subtypes subtype;
+  /*! List of tasks unlocked by this one */
+  struct task **unlock_tasks;
+
+  /*! Start and end time of this task */
+  ticks tic, toc;
+
+#ifdef WITH_MPI
+
+  /*! Buffer for this task's communications */
+  void *buff;
+
+  /*! MPI request corresponding to this task */
+  MPI_Request req;
+
+#endif
 
   /*! Flags used to carry additional information (e.g. sort directions) */
   int flags;
 
-  /*! Number of unsatisfied dependencies */
-  int wait;
-
   /*! Rank of a task in the order */
   int rank;
 
   /*! Weight of the task */
   int weight;
 
-  /*! Pointers to the cells this task acts upon */
-  struct cell *ci, *cj;
-
   /*! ID of the queue or runner owning this task */
-  int rid;
+  short int rid;
 
   /*! Number of tasks unlocked by this one */
-  int nr_unlock_tasks;
-
-  /*! List of tasks unlocked by this one */
-  struct task **unlock_tasks;
-
-#ifdef WITH_MPI
-
-  /*! Buffer for this task's communications */
-  void *buff;
+  short int nr_unlock_tasks;
 
-  /*! MPI request corresponding to this task */
-  MPI_Request req;
+  /*! Number of unsatisfied dependencies */
+  short int wait;
 
-#endif
+  /*! Type of the task */
+  enum task_types type;
 
-  /*! Start and end time of this task */
-  ticks tic, toc;
+  /*! Sub-type of the task (for the tasks that have one */
+  enum task_subtypes subtype;
 
   /*! Should the scheduler skip this task ? */
   char skip;
@@ -145,7 +147,8 @@ struct task {
 
   /*! Is this task implicit (i.e. does not do anything) ? */
   char implicit;
-};
+
+} __attribute__((aligned(32)));
 
 /* Function prototypes. */
 void task_unlock(struct task *t);