add arena stats

include/mimalloc/types.h

@@ -547,6 +547,9 @@ typedef struct mi_stats_s {
   mi_stat_counter_t normal_count;
   mi_stat_counter_t huge_count;
   mi_stat_counter_t giant_count;
+  mi_stat_counter_t arena_count;
+  mi_stat_counter_t arena_crossover_count;
+  mi_stat_counter_t arena_rollback_count;
 #if MI_STAT>1
   mi_stat_count_t normal_bins[MI_BIN_HUGE+1];
 #endif

src/arena.c

@@ -207,10 +207,10 @@ static void* mi_arena_block_start(mi_arena_t* arena, mi_bitmap_index_t bindex) {
 ----------------------------------------------------------- */
 
 // claim the `blocks_inuse` bits
-static bool mi_arena_try_claim(mi_arena_t* arena, size_t blocks, mi_bitmap_index_t* bitmap_idx)
+static bool mi_arena_try_claim(mi_arena_t* arena, size_t blocks, mi_bitmap_index_t* bitmap_idx, mi_stats_t* stats)
 {
   size_t idx = 0; // mi_atomic_load_relaxed(&arena->search_idx);  // start from last search; ok to be relaxed as the exact start does not matter
-  if (_mi_bitmap_try_find_from_claim_across(arena->blocks_inuse, arena->field_count, idx, blocks, bitmap_idx)) {
+  if (_mi_bitmap_try_find_from_claim_across(arena->blocks_inuse, arena->field_count, idx, blocks, bitmap_idx, stats)) {
     mi_atomic_store_relaxed(&arena->search_idx, mi_bitmap_index_field(*bitmap_idx));  // start search from found location next time around
     return true;
   };
@@ -229,7 +229,7 @@ static mi_decl_noinline void* mi_arena_try_alloc_at(mi_arena_t* arena, size_t ar
   mi_assert_internal(mi_arena_id_index(arena->id) == arena_index);
 
   mi_bitmap_index_t bitmap_index;
-  if (!mi_arena_try_claim(arena, needed_bcount, &bitmap_index)) return NULL;
+  if (!mi_arena_try_claim(arena, needed_bcount, &bitmap_index, tld->stats)) return NULL;
 
   // claimed it!
   void* p = mi_arena_block_start(arena, bitmap_index);
@@ -735,7 +735,7 @@ bool _mi_arena_contains(const void* p) {
   Add an arena.
 ----------------------------------------------------------- */
 
-static bool mi_arena_add(mi_arena_t* arena, mi_arena_id_t* arena_id) {
+static bool mi_arena_add(mi_arena_t* arena, mi_arena_id_t* arena_id, mi_stats_t* stats) {
   mi_assert_internal(arena != NULL);
   mi_assert_internal((uintptr_t)mi_atomic_load_ptr_relaxed(uint8_t,&arena->start) % MI_SEGMENT_ALIGN == 0);
   mi_assert_internal(arena->block_count > 0);
@@ -746,6 +746,7 @@ static bool mi_arena_add(mi_arena_t* arena, mi_arena_id_t* arena_id) {
     mi_atomic_decrement_acq_rel(&mi_arena_count);
     return false;
   }
+  mi_stat_counter_increase(stats->arena_count,1);
   arena->id = mi_arena_id_create(i);
   mi_atomic_store_ptr_release(mi_arena_t,&mi_arenas[i], arena);
   if (arena_id != NULL) { *arena_id = arena->id; }
@@ -799,7 +800,7 @@ static bool mi_manage_os_memory_ex2(void* start, size_t size, bool is_large, int
     mi_bitmap_index_t postidx = mi_bitmap_index_create(fields - 1, MI_BITMAP_FIELD_BITS - post);
     _mi_bitmap_claim(arena->blocks_inuse, fields, post, postidx, NULL);
   }
-  return mi_arena_add(arena, arena_id);
+  return mi_arena_add(arena, arena_id, &_mi_stats_main);
 
 }
 

src/bitmap.c

@@ -182,7 +182,7 @@ bool _mi_bitmap_is_any_claimed(mi_bitmap_t bitmap, size_t bitmap_fields, size_t
 // Try to atomically claim a sequence of `count` bits starting from the field
 // at `idx` in `bitmap` and crossing into subsequent fields. Returns `true` on success.
 // Only needs to consider crossing into the next fields (see `mi_bitmap_try_find_from_claim_across`)
-static bool mi_bitmap_try_find_claim_field_across(mi_bitmap_t bitmap, size_t bitmap_fields, size_t idx, const size_t count, const size_t retries, mi_bitmap_index_t* bitmap_idx)
+static bool mi_bitmap_try_find_claim_field_across(mi_bitmap_t bitmap, size_t bitmap_fields, size_t idx, const size_t count, const size_t retries, mi_bitmap_index_t* bitmap_idx, mi_stats_t* stats)
 {
   mi_assert_internal(bitmap_idx != NULL);
 
@@ -242,6 +242,7 @@ static bool mi_bitmap_try_find_claim_field_across(mi_bitmap_t bitmap, size_t bit
   } while (!mi_atomic_cas_strong_acq_rel(field, &map, newmap));
 
   // claimed!
+  mi_stat_counter_increase(stats->arena_crossover_count,1);
   *bitmap_idx = mi_bitmap_index_create(idx, initial_idx);
   return true;
 
@@ -261,9 +262,10 @@ rollback:
       newmap = (map & ~initial_mask);
     } while (!mi_atomic_cas_strong_acq_rel(field, &map, newmap));
   }
+  mi_stat_counter_increase(stats->arena_rollback_count,1);
   // retry? (we make a recursive call instead of goto to be able to use const declarations)
   if (retries <= 2) {
-    return mi_bitmap_try_find_claim_field_across(bitmap, bitmap_fields, idx, count, retries+1, bitmap_idx);
+    return mi_bitmap_try_find_claim_field_across(bitmap, bitmap_fields, idx, count, retries+1, bitmap_idx, stats);
   }
   else {
     return false;
@@ -273,7 +275,7 @@ rollback:
 
 // Find `count` bits of zeros and set them to 1 atomically; returns `true` on success.
 // Starts at idx, and wraps around to search in all `bitmap_fields` fields.
-bool _mi_bitmap_try_find_from_claim_across(mi_bitmap_t bitmap, const size_t bitmap_fields, const size_t start_field_idx, const size_t count, mi_bitmap_index_t* bitmap_idx) {
+bool _mi_bitmap_try_find_from_claim_across(mi_bitmap_t bitmap, const size_t bitmap_fields, const size_t start_field_idx, const size_t count, mi_bitmap_index_t* bitmap_idx, mi_stats_t* stats) {
   mi_assert_internal(count > 0);
   if (count <= 2) {
     // we don't bother with crossover fields for small counts
@@ -285,13 +287,15 @@ bool _mi_bitmap_try_find_from_claim_across(mi_bitmap_t bitmap, const size_t bitm
   for (size_t visited = 0; visited < bitmap_fields; visited++, idx++) {
     if (idx >= bitmap_fields) { idx = 0; } // wrap
     // first try to claim inside a field
+    /*
     if (count <= MI_BITMAP_FIELD_BITS) {
       if (_mi_bitmap_try_find_claim_field(bitmap, idx, count, bitmap_idx)) {
         return true;
       }
     }
+    */
     // if that fails, then try to claim across fields
-    if (mi_bitmap_try_find_claim_field_across(bitmap, bitmap_fields, idx, count, 0, bitmap_idx)) {
+    if (mi_bitmap_try_find_claim_field_across(bitmap, bitmap_fields, idx, count, 0, bitmap_idx, stats)) {
       return true;
     }
   }

src/bitmap.h

@@ -90,7 +90,7 @@ bool _mi_bitmap_is_any_claimed(mi_bitmap_t bitmap, size_t bitmap_fields, size_t
 
 // Find `count` bits of zeros and set them to 1 atomically; returns `true` on success.
 // Starts at idx, and wraps around to search in all `bitmap_fields` fields.
-bool _mi_bitmap_try_find_from_claim_across(mi_bitmap_t bitmap, const size_t bitmap_fields, const size_t start_field_idx, const size_t count, mi_bitmap_index_t* bitmap_idx);
+bool _mi_bitmap_try_find_from_claim_across(mi_bitmap_t bitmap, const size_t bitmap_fields, const size_t start_field_idx, const size_t count, mi_bitmap_index_t* bitmap_idx, mi_stats_t* stats);
 
 // Set `count` bits at `bitmap_idx` to 0 atomically
 // Returns `true` if all `count` bits were 1 previously.

src/init.c

@@ -78,7 +78,8 @@ const mi_page_t _mi_page_empty = {
   MI_STAT_COUNT_NULL(), MI_STAT_COUNT_NULL(), \
   MI_STAT_COUNT_NULL(), \
   { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 }, \
-  { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } \
+  { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 }, \
+  { 0, 0 }, { 0, 0 }, { 0, 0 } \
   MI_STAT_COUNT_END_NULL()
 
 // --------------------------------------------------------

src/stats.c

@@ -340,6 +340,9 @@ static void _mi_stats_print(mi_stats_t* stats, mi_output_fun* out0, void* arg0)
   mi_stat_print(&stats->pages_abandoned, "-abandoned", -1, out, arg);
   mi_stat_counter_print(&stats->pages_extended, "-extended", out, arg);
   mi_stat_counter_print(&stats->page_no_retire, "-noretire", out, arg);
+  mi_stat_counter_print(&stats->arena_count, "arenas", out, arg);
+  mi_stat_counter_print(&stats->arena_crossover_count, "-crossover", out, arg);
+  mi_stat_counter_print(&stats->arena_rollback_count, "-rollback", out, arg);
   mi_stat_counter_print(&stats->mmap_calls, "mmaps", out, arg);
   mi_stat_counter_print(&stats->commit_calls, "commits", out, arg);
   mi_stat_counter_print(&stats->reset_calls, "resets", out, arg);