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GH-117108: Change the size of the GC increment to about 1% of the total heap size. (GH-117120)

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Mark Shannon 2024-03-22 18:43:25 +00:00 • committed by GitHub
parent e2e0b4b4b9
commit e28477f214
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6 changed files with 47 additions and 28 deletions
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30
Python/gc.c
View file

@ -182,6 +182,7 @@ _PyGC_Init(PyInterpreterState *interp)
if (gcstate->callbacks == NULL) {
return _PyStatus_NO_MEMORY();
}
gcstate->heap_size = 0;
return _PyStatus_OK();
}
@ -1232,7 +1233,7 @@ gc_collect_region(PyThreadState *tstate,
struct gc_collection_stats *stats);
static inline Py_ssize_t
gc_list_set_space(PyGC_Head *list, uintptr_t space)
gc_list_set_space(PyGC_Head *list, int space)
{
Py_ssize_t size = 0;
PyGC_Head *gc;
@ -1258,9 +1259,9 @@ gc_list_set_space(PyGC_Head *list, uintptr_t space)
* N == 1.4 (1 + 4/threshold)
*/
/* Multiply by 4 so that the default incremental threshold of 10
* scans objects at 20% the rate of object creation */
#define SCAN_RATE_MULTIPLIER 2
/* Divide by 10, so that the default incremental threshold of 10
* scans objects at 1% of the heap size */
#define SCAN_RATE_DIVISOR 10
static void
add_stats(GCState *gcstate, int gen, struct gc_collection_stats *stats)
@ -1313,7 +1314,7 @@ gc_collect_young(PyThreadState *tstate,
if (scale_factor < 1) {
scale_factor = 1;
}
gcstate->work_to_do += survivor_count + survivor_count * SCAN_RATE_MULTIPLIER / scale_factor;
gcstate->work_to_do += gcstate->heap_size / SCAN_RATE_DIVISOR / scale_factor;
add_stats(gcstate, 0, stats);
}
@ -1384,12 +1385,12 @@ expand_region_transitively_reachable(PyGC_Head *container, PyGC_Head *gc, GCStat
static void
completed_cycle(GCState *gcstate)
{
#ifdef Py_DEBUG
PyGC_Head *not_visited = &gcstate->old[gcstate->visited_space^1].head;
assert(gc_list_is_empty(not_visited));
#endif
gcstate->visited_space = flip_old_space(gcstate->visited_space);
if (gcstate->work_to_do > 0) {
gcstate->work_to_do = 0;
}
gcstate->work_to_do = 0;
}
static void
@ -1404,13 +1405,13 @@ gc_collect_increment(PyThreadState *tstate, struct gc_collection_stats *stats)
if (scale_factor < 1) {
scale_factor = 1;
}
Py_ssize_t increment_size = 0;
gc_list_merge(&gcstate->young.head, &increment);
gcstate->young.count = 0;
if (gcstate->visited_space) {
/* objects in visited space have bit set, so we set it here */
gc_list_set_space(&increment, 1);
}
Py_ssize_t increment_size = 0;
while (increment_size < gcstate->work_to_do) {
if (gc_list_is_empty(not_visited)) {
break;
@ -1425,14 +1426,11 @@ gc_collect_increment(PyThreadState *tstate, struct gc_collection_stats *stats)
PyGC_Head survivors;
gc_list_init(&survivors);
gc_collect_region(tstate, &increment, &survivors, UNTRACK_TUPLES, stats);
Py_ssize_t survivor_count = gc_list_size(&survivors);
gc_list_merge(&survivors, visited);
assert(gc_list_is_empty(&increment));
gcstate->work_to_do += survivor_count + survivor_count * SCAN_RATE_MULTIPLIER / scale_factor;
gcstate->work_to_do += gcstate->heap_size / SCAN_RATE_DIVISOR / scale_factor;
gcstate->work_to_do -= increment_size;
if (gcstate->work_to_do < 0) {
gcstate->work_to_do = 0;
}
validate_old(gcstate);
add_stats(gcstate, 1, stats);
if (gc_list_is_empty(not_visited)) {
@ -1678,7 +1676,7 @@ _PyGC_GetReferrers(PyInterpreterState *interp, PyObject *objs)
}
PyObject *
_PyGC_GetObjects(PyInterpreterState *interp, Py_ssize_t generation)
_PyGC_GetObjects(PyInterpreterState *interp, int generation)
{
assert(generation >= -1 && generation < NUM_GENERATIONS);
GCState *gcstate = &interp->gc;
@ -1974,6 +1972,7 @@ _PyObject_GC_Link(PyObject *op)
gc->_gc_next = 0;
gc->_gc_prev = 0;
gcstate->young.count++; /* number of allocated GC objects */
gcstate->heap_size++;
if (gcstate->young.count > gcstate->young.threshold &&
gcstate->enabled &&
gcstate->young.threshold &&
@ -2095,6 +2094,7 @@ PyObject_GC_Del(void *op)
if (gcstate->young.count > 0) {
gcstate->young.count--;
}
gcstate->heap_size--;
PyObject_Free(((char *)op)-presize);
}

2
Python/gc_free_threading.c
View file

@ -1305,7 +1305,7 @@ visit_get_objects(const mi_heap_t *heap, const mi_heap_area_t *area,
}
PyObject *
_PyGC_GetObjects(PyInterpreterState *interp, Py_ssize_t generation)
_PyGC_GetObjects(PyInterpreterState *interp, int generation)
{
PyObject *result = PyList_New(0);
if (!result) {