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eo_ptr_ind: pack ptr, active flag and generation all together 

use of an array of the below struct instead of 3 separate arrays
leads to better cache performance and smaller memory usage
typedef struct
{
  _Eo *ptr;
  unsigned int active     : 1;
  unsigned int generation : BITS_FOR_GENERATION_COUNTER;
} _Eo_Id_Entry;
This commit is contained in:
Jérémy Zurcher 2013-04-28 00:43:23 +02:00
parent 41dc1764f3
commit 994318eebe
1 changed files with 56 additions and 55 deletions
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111
src/lib/eo/eo_ptr_indirection.c
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@ -32,9 +32,10 @@
* occur when accessing with the old id.
*
* Each table is composed of:
* - pointers to the objects
* - generations assigned to the objects
* - a boolean table indicating if an entry is active
* - entries composed of
* - a pointer to the object
* - a flag indicating if the entry is active
* - a generation assigned to the object
* - an index 'start' indicating which entry is the next one to use.
* - a queue that will help us to store the unused entries. It stores only the
* entries that have been used at least one time. The entries that have
@ -112,7 +113,7 @@ _eo_id_mem_alloc(size_t size)
return (void *)(((unsigned char *)ptr) + MEM_HEADER_SIZE);
#else
return malloc(size);
#endif
#endif
}
static void *
@ -142,15 +143,22 @@ _eo_id_mem_free(void *ptr)
#endif
}
/* Entry */
typedef struct
{
/* Pointer to the object */
_Eo *ptr;
/* Active flag */
unsigned int active : 1;
/* Generation */
unsigned int generation : BITS_FOR_GENERATION_COUNTER;
} _Eo_Id_Entry;
/* Table */
typedef struct
{
/* Pointers of objects stored in table */
_Eo *ptrs[MAX_IDS_PER_TABLE];
/* Generations */
Table_Index generation[MAX_IDS_PER_TABLE];
/* Active flags */
char active[MAX_IDS_PER_TABLE >> 3];
/* Entries of the table holding real pointers and generations */
_Eo_Id_Entry entries[MAX_IDS_PER_TABLE];
/* Queue to handle free entries */
Eina_Trash *queue;
/* Indicates where start the "never used" entries */
@ -163,20 +171,6 @@ _Eo_Ids_Table **_eo_ids_tables[MAX_IDS_TABLES] = { NULL };
/* Next generation to use when assigning a new entry to a Eo pointer */
Table_Index _eo_generation_counter;
/* Internal macro for active flag manipulation */
#define _ENTRY_ACTIVE_DO_OP(table, id_in_table, op) \
(table)->active[(id_in_table) >> 3] op (1 << ((id_in_table) % 8))
/* Macro that indicates if an entry is active */
#define IS_ENTRY_ACTIVE(table, id_in_table) \
(_ENTRY_ACTIVE_DO_OP(table, id_in_table, &))
/* Macro that activates an entry */
#define ACTIVATE_ENTRY(table, id_in_table) \
_ENTRY_ACTIVE_DO_OP(table, id_in_table, |=)
/* Macro that de-activates an entry */
#define DEACTIVATE_ENTRY(table, id_in_table) \
_ENTRY_ACTIVE_DO_OP(table, id_in_table, &=~)
/* Macro used to compose an Eo id */
#define EO_COMPOSE_ID(TABLE, INTER_TABLE, ENTRY, GENERATION) \
(Eo_Id)(((TABLE & (MAX_IDS_TABLES - 1)) << SHIFT_FOR_IDS_TABLE) | \
@ -198,14 +192,18 @@ _Eo *
_eo_obj_pointer_get(const Eo_Id obj_id)
{
#ifdef HAVE_EO_ID
_Eo_Id_Entry *entry;
Table_Index table_id, int_table_id, entry_id, generation;
EO_DECOMPOSE_ID((Table_Index) obj_id, table_id, int_table_id, entry_id, generation);
/* Checking the validity of the entry */
if (_eo_ids_tables[table_id] && ID_TABLE && IS_ENTRY_ACTIVE(ID_TABLE, entry_id) &&
ID_TABLE->generation[entry_id] == generation)
return ID_TABLE->ptrs[entry_id];
if (_eo_ids_tables[table_id] && ID_TABLE)
{
entry = &(ID_TABLE->entries[entry_id]);
if (entry && entry->active && (entry->generation == generation))
return entry->ptr;
}
ERR("obj_id %p is not pointing to a valid object. Maybe it has already been freed.",
(void *)obj_id);
@ -220,7 +218,7 @@ Eo_Id
_eo_id_allocate(const _Eo *obj)
{
#ifdef HAVE_EO_ID
Eo_Id ret = 0;
_Eo_Id_Entry *entry = NULL;
for (Table_Index table_id = 1; table_id < MAX_IDS_TABLES; table_id++)
{
if (!_eo_ids_tables[table_id])
@ -230,44 +228,43 @@ _eo_id_allocate(const _Eo *obj)
}
for (Table_Index int_table_id = 0; int_table_id < MAX_IDS_INTER_TABLES; int_table_id++)
{
_Eo **ptr;
if (!ID_TABLE)
{
/* We allocate a new intermediate table */
ID_TABLE = _eo_id_mem_calloc(1, sizeof(_Eo_Ids_Table));
eina_trash_init(&(ID_TABLE->queue));
/* We select directly the first entry of the new table */
ptr = &(ID_TABLE->ptrs[0]);
entry = &(ID_TABLE->entries[0]);
ID_TABLE->start = 1;
}
else
{
/* We try to pop from the queue an unused entry */
ptr = (_Eo **)eina_trash_pop(&(ID_TABLE->queue));
entry = (_Eo_Id_Entry *)eina_trash_pop(&(ID_TABLE->queue));
}
if (!ptr && ID_TABLE->start < MAX_IDS_PER_TABLE)
if (!entry && ID_TABLE->start < MAX_IDS_PER_TABLE)
{
/* No more unused entries in the trash but still empty entries in the table */
ptr = &(ID_TABLE->ptrs[ID_TABLE->start]);
entry = &(ID_TABLE->entries[ID_TABLE->start]);
ID_TABLE->start++;
}
if (ptr)
if (entry)
{
/* An entry was found - need to find the entry id and fill it */
Table_Index id = ptr - ID_TABLE->ptrs;
ID_TABLE->generation[id] = _eo_generation_counter;
ACTIVATE_ENTRY(ID_TABLE, id);
*ptr = (_Eo *)obj;
ret = EO_COMPOSE_ID(table_id, int_table_id, id, _eo_generation_counter);
entry->ptr = (_Eo *)obj;
entry->active = 1;
entry->generation = _eo_generation_counter;
_eo_generation_counter++;
_eo_generation_counter %= MAX_GENERATIONS;
return ret;
return EO_COMPOSE_ID(table_id, int_table_id,
(entry - ID_TABLE->entries),
entry->generation);
}
}
}
return ret;
return 0;
#else
return (Eo_Id)obj;
#endif
@ -277,22 +274,24 @@ void
_eo_id_release(const Eo_Id obj_id)
{
#ifdef HAVE_EO_ID
_Eo_Id_Entry *entry;
Table_Index table_id, int_table_id, entry_id, generation;
EO_DECOMPOSE_ID((Table_Index) obj_id, table_id, int_table_id, entry_id, generation);
/* Checking the validity of the entry */
if (!_eo_ids_tables[table_id]) goto error;
if (!ID_TABLE) goto error;
if (ID_TABLE->generation[entry_id] != generation) goto error;
if (_eo_ids_tables[table_id] && ID_TABLE)
{
entry = &(ID_TABLE->entries[entry_id]);
if (entry && entry->active && (entry->generation == generation))
{
/* Disable the entry */
entry->active = 0;
/* Push the entry into the queue */
eina_trash_push(&(ID_TABLE->queue), entry);
return;
}
}
/* Disable the entry */
DEACTIVATE_ENTRY(ID_TABLE, entry_id);
/* Push the entry into the queue */
eina_trash_push(&(ID_TABLE->queue), &(ID_TABLE->ptrs[entry_id]));
return;
error:
ERR("obj_id %p is not pointing to a valid object. Maybe it has already been freed.", (void *)obj_id);
#else
(void) obj_id;
@ -323,6 +322,7 @@ _eo_free_ids_tables()
void
_eo_print()
{
_Eo_Id_Entry *entry;
unsigned long obj_number = 0;
for (Table_Index table_id = 0; table_id < MAX_IDS_TABLES; table_id++)
{
@ -334,12 +334,13 @@ _eo_print()
{
for (Table_Index entry_id = 0; entry_id < MAX_IDS_PER_TABLE; entry_id++)
{
if (IS_ENTRY_ACTIVE(ID_TABLE, entry_id))
entry = &(ID_TABLE->entries[entry_id]);
if (entry->active)
{
printf("%ld: %p -> (%p, %p, %p, %p)\n", obj_number++,
ID_TABLE->ptrs[entry_id],
entry->ptr,
(void *)table_id, (void *)int_table_id, (void *)entry_id,
(void *)ID_TABLE->generation[entry_id]);
(void *)entry->generation);
}
}
}