Bug #8122

[patch] gc: GC.stat improvements and related cleanup

Added by Aman Gupta about 2 years ago. Updated over 1 year ago.

[ruby-core:53523]
Status:Closed
Priority:Normal
Assignee:Koichi Sasada
ruby -v:ruby 2.1.0dev (2013-03-19 trunk 39816) [x86_64-darwin12.2.1] Backport:

Description

I propose 4 related patches below. The end result is more information from GC.stat about mark and sweep activity.

1) Rename heap.free_num to heap.swept_num
This is a purely cosmetic change, to make the purpose of the variable more clear and avoid problems due to misuse later (like we saw in r39811)
I considered some other names: heap.freelisted_num, heap.reused_num

2) Add heap.sweep_num
We already calculate heap.marked_num during mark. This is inverse of marked_num calculated at the end of mark cycle.
Using this you can monitor progress of sweep cycle: (100% * heap.swept_num / heap.sweep_num)
I considered also: heap.sweeping_num

3) Remove rest_sweep() from GC.stat
Currently sweep is a side-effect of GC.stat. It makes GC.stat difficult to use for statistics, because it is not constant time operation.
Also, after rest_sweep(), heap.swept_num == heap.sweep_num, so GC.stat cannot be used to track progress of sweep cycle.

4) Expose new mark/sweep counters via GC.stat

Author: Aman Gupta aman@tmm1.net
Date: Mon Mar 18 18:11:27 2013 -0700

rename heap.free_num to heap.swept_num

diff --git a/gc.c b/gc.c
index 635e3ec..f654e19 100644
--- a/gc.c
+++ b/gc.c
@@ -229,7 +229,7 @@ typedef struct rb_objspace {
RVALUE range[2];
struct heaps_header *freed;
size_t marked_num;
- size_t free_num;
+ size_t swept_num;
size_t free_min;
size_t final_num;
size_t do_heap_free;
@@ -1434,7 +1434,7 @@ finalize_list(rb_objspace_t *objspace, RVALUE *p)
objspace->total_freed_object_num++;
if (!FL_TEST(p, FL_SINGLETON)) { /
not freeing page */
add_slot_local_freelist(objspace, p);
- objspace->heap.free_num++;
+ objspace->heap.swept_num++;
}
else {
struct heaps_slot *slot = (struct heaps_slot *)(VALUE)RDATA(p)->dmark;
@@ -1921,7 +1921,7 @@ slot_sweep(rb_objspace_t *objspace, struct heaps_slot *sweep_slot)
}
gc_clear_slot_bits(sweep_slot);
if (final_num + freed_num + empty_num == sweep_slot->header->limit &&
- objspace->heap.free_num > objspace->heap.do_heap_free) {
+ objspace->heap.swept_num > objspace->heap.do_heap_free) {
RVALUE *pp;

     for (pp = deferred_final_list; pp != final; pp = pp->as.free.next) {

@@ -1938,7 +1938,7 @@ slot_sweep(rb_objspace_t *objspace, struct heaps_slot *sweep_slot)
else {
sweep_slot->free_next = NULL;
}
- objspace->heap.free_num += freed_num + empty_num;
+ objspace->heap.swept_num += freed_num + empty_num;
}
objspace->total_freed_object_num += freed_num;
objspace->heap.final_num += final_num;
@@ -1977,7 +1977,7 @@ before_gc_sweep(rb_objspace_t *objspace)
objspace->heap.do_heap_free = initial_free_min;
}
objspace->heap.sweep_slots = heaps;
- objspace->heap.free_num = 0;
+ objspace->heap.swept_num = 0;
objspace->heap.free_slots = NULL;

 /* sweep unlinked method entries */

@@ -1992,7 +1992,7 @@ after_gc_sweep(rb_objspace_t *objspace)
size_t inc;

 gc_prof_set_malloc_info(objspace);
  • if (objspace->heap.free_num < objspace->heap.free_min) {
  • if (objspace->heap.swept_num < objspace->heap.free_min) { set_heaps_increment(objspace); heaps_increment(objspace); } @@ -2972,7 +2972,7 @@ rb_gc_force_recycle(VALUE p) add_slot_local_freelist(objspace, (RVALUE *)p); } else {
  • objspace->heap.free_num++;
  • objspace->heap.swept_num++; slot = add_slot_local_freelist(objspace, (RVALUE *)p); if (slot->free_next == NULL) { link_free_heap_slot(objspace, slot); @@ -3205,7 +3205,7 @@ gc_stat(int argc, VALUE *argv, VALUE self) rb_hash_aset(hash, sym_heap_length, SIZET2NUM(objspace->heap.length)); rb_hash_aset(hash, sym_heap_increment, SIZET2NUM(objspace->heap.increment)); rb_hash_aset(hash, sym_heap_live_num, SIZET2NUM(objspace_live_num(objspace)));
  • rb_hash_aset(hash, sym_heap_free_num, SIZET2NUM(objspace->heap.free_num));
  • rb_hash_aset(hash, sym_heap_free_num, SIZET2NUM(objspace->heap.swept_num)); rb_hash_aset(hash, sym_heap_final_num, SIZET2NUM(objspace->heap.final_num)); rb_hash_aset(hash, sym_total_allocated_object, SIZET2NUM(objspace->total_allocated_object_num)); rb_hash_aset(hash, sym_total_freed_object, SIZET2NUM(objspace->total_freed_object_num));

Author: Aman Gupta aman@tmm1.net
Date: Mon Mar 18 18:32:58 2013 -0700

add sweep_num

diff --git a/gc.c b/gc.c
index b911d04..c49f1dd 100644
--- a/gc.c
+++ b/gc.c
@@ -229,6 +229,7 @@ typedef struct rb_objspace {
RVALUE *range[2];
struct heaps_header *freed;
size_t marked_num;
+ size_t sweep_num;
size_t swept_num;
size_t free_min;
size_t final_num;
@@ -2957,6 +2958,7 @@ gc_marks(rb_objspace_t *objspace)
gc_prof_mark_timer_stop(objspace);

 objspace->mark_func_data = prev_mark_func_data;
  • objspace->heap.sweep_num = (heaps_used * HEAP_OBJ_LIMIT) - objspace->heap.marked_num; }

/* GC */

Author: Aman Gupta aman@tmm1.net
Date: Mon Mar 18 18:14:10 2013 -0700

remove rest_sweep side-effect from GC.stat

diff --git a/gc.c b/gc.c
index f654e19..b911d04 100644
--- a/gc.c
+++ b/gc.c
@@ -3197,8 +3197,6 @@ gc_stat(int argc, VALUE *argv, VALUE self)
hash = rb_hash_new();
}

- rest_sweep(objspace);

 rb_hash_aset(hash, sym_count, SIZET2NUM(objspace->count));
 /* implementation dependent counters */
 rb_hash_aset(hash, sym_heap_used, SIZET2NUM(objspace->heap.used));

Author: Aman Gupta aman@tmm1.net
Date: Mon Mar 18 18:59:50 2013 -0700

add more stats to GC.stat

diff --git a/gc.c b/gc.c
index c49f1dd..8f458db 100644
--- a/gc.c
+++ b/gc.c
@@ -3174,18 +3174,28 @@ gc_stat(int argc, VALUE *argv, VALUE self)
{
rb_objspace_t *objspace = &rb_objspace;
VALUE hash;
+ size_t total_num, live_num;
static VALUE sym_count;
static VALUE sym_heap_used, sym_heap_length, sym_heap_increment;
- static VALUE sym_heap_live_num, sym_heap_free_num, sym_heap_final_num;
+ static VALUE sym_heap_obj_limit, sym_heap_total_num;
+ static VALUE sym_heap_live_num, sym_heap_empty_num, sym_heap_final_num;
+ static VALUE sym_heap_marked_num, sym_heap_sweep_num, sym_heap_swept_num;
+ static VALUE sym_is_lazy_sweeping;
static VALUE sym_total_allocated_object, sym_total_freed_object;
if (sym_count == 0) {
sym_count = ID2SYM(rb_intern_const("count"));
sym_heap_used = ID2SYM(rb_intern_const("heap_used"));
sym_heap_length = ID2SYM(rb_intern_const("heap_length"));
sym_heap_increment = ID2SYM(rb_intern_const("heap_increment"));
+ sym_heap_obj_limit = ID2SYM(rb_intern_const("heap_obj_limit"));
+ sym_heap_total_num = ID2SYM(rb_intern_const("heap_total_num"));
sym_heap_live_num = ID2SYM(rb_intern_const("heap_live_num"));
- sym_heap_free_num = ID2SYM(rb_intern_const("heap_free_num"));
+ sym_heap_empty_num = ID2SYM(rb_intern_const("heap_empty_num"));
sym_heap_final_num = ID2SYM(rb_intern_const("heap_final_num"));
+ sym_heap_marked_num = ID2SYM(rb_intern_const("heap_marked_num"));
+ sym_heap_sweep_num = ID2SYM(rb_intern_const("heap_sweep_num"));
+ sym_heap_swept_num = ID2SYM(rb_intern_const("heap_swept_num"));
+ sym_is_lazy_sweeping = ID2SYM(rb_intern_const("is_lazy_sweeping"));
sym_total_allocated_object = ID2SYM(rb_intern_const("total_allocated_object"));
sym_total_freed_object = ID2SYM(rb_intern_const("total_freed_object"));
}
@@ -3201,12 +3211,21 @@ gc_stat(int argc, VALUE *argv, VALUE self)

 rb_hash_aset(hash, sym_count, SIZET2NUM(objspace->count));
 /* implementation dependent counters */
  • total_num = heaps_used * HEAP_OBJ_LIMIT;
  • live_num = objspace_live_num(objspace); + rb_hash_aset(hash, sym_heap_used, SIZET2NUM(objspace->heap.used)); rb_hash_aset(hash, sym_heap_length, SIZET2NUM(objspace->heap.length)); rb_hash_aset(hash, sym_heap_increment, SIZET2NUM(objspace->heap.increment));
  • rb_hash_aset(hash, sym_heap_live_num, SIZET2NUM(objspace_live_num(objspace)));
  • rb_hash_aset(hash, sym_heap_free_num, SIZET2NUM(objspace->heap.swept_num));
  • rb_hash_aset(hash, sym_heap_obj_limit, SIZET2NUM(HEAP_OBJ_LIMIT));
  • rb_hash_aset(hash, sym_heap_total_num, SIZET2NUM(total_num));
  • rb_hash_aset(hash, sym_heap_live_num, SIZET2NUM(live_num));
  • rb_hash_aset(hash, sym_heap_empty_num, SIZET2NUM(total_num - live_num)); rb_hash_aset(hash, sym_heap_final_num, SIZET2NUM(objspace->heap.final_num));
  • rb_hash_aset(hash, sym_is_lazy_sweeping, is_lazy_sweeping(objspace) ? Qtrue : Qfalse);
  • rb_hash_aset(hash, sym_heap_marked_num, SIZET2NUM(objspace->heap.marked_num));
  • rb_hash_aset(hash, sym_heap_swept_num, SIZET2NUM(objspace->heap.swept_num));
  • rb_hash_aset(hash, sym_heap_sweep_num, SIZET2NUM(objspace->heap.sweep_num)); rb_hash_aset(hash, sym_total_allocated_object, SIZET2NUM(objspace->total_allocated_object_num)); rb_hash_aset(hash, sym_total_freed_object, SIZET2NUM(objspace->total_freed_object_num));

History

#1 Updated by Narihiro Nakamura about 2 years ago

  • Assignee changed from Narihiro Nakamura to Koichi Sasada

ko1-san, what do you think?

#2 Updated by Koichi Sasada about 2 years ago

(2013/03/19 11:58), authorNari (Narihiro Nakamura) wrote:

ko1-san, what do you think?

(1) Performance

One concern is making it fat seems slow it down.

(2) Usage

How to use new statistics?

--
// SASADA Koichi at atdot dot net

#3 Updated by Koichi Sasada over 1 year ago

  • Target version set to 2.1.0

#4 Updated by Aman Gupta over 1 year ago

  • Status changed from Open to Closed
  • % Done changed from 0 to 100

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