[GR-31106] Optimize GC.stat(key) when key is not set

PullRequest: truffleruby/2621

Author: eregon

src/main/ruby/truffleruby/core/gc.rb

@@ -34,6 +34,79 @@
 # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+module Truffle::GCOperations
+  KNOWN_KEYS = %i[
+    count
+    time
+    minor_gc_count
+    major_gc_count
+    unknown_count
+    heap_available_slots
+    heap_live_slots
+    heap_free_slots
+    used
+    committed
+    init
+    max
+  ]
+
+  def self.stat_hash(key = nil)
+    time, count, minor_count, major_count, unknown_count, heap, memory_pool_names, memory_pool_info = Primitive.gc_stat
+    used, committed, init, max = heap
+
+    # Initialize stat for statistics that come from memory pools, and populate it with some final stats (ordering similar to MRI)
+    stat = {
+        count: count,
+        time: time,
+        minor_gc_count: minor_count,
+        major_gc_count: major_count,
+        unknown_count: unknown_count, # if nonzero, major or minor count needs to be updated for this GC case
+        heap_available_slots: committed,
+        heap_live_slots: used,
+        heap_free_slots: committed - used,
+        used: used,
+        committed: committed,
+        init: init,
+        max: max,
+    }
+    stat.default = 0
+
+    unless Primitive.object_kind_of?(key, Symbol) # memory_pool_names are Strings
+      memory_pool_names.each_with_index do |memory_pool_name, i|
+        # Populate memory pool specific stats
+        info = memory_pool_info[i]
+        if info
+          stat[memory_pool_name] = data = {
+              used: info[0],
+              committed: info[1],
+              init: info[2],
+              max: info[3],
+              peak_used: info[4],
+              peak_committed: info[5],
+              peak_init: info[6],
+              peak_max: info[7],
+              last_used: info[8],
+              last_committed: info[9],
+              last_init: info[10],
+              last_max: info[11],
+          }
+
+          # Calculate stats across memory pools for peak_/last_ (we already know the values for current usage)
+          data.each_pair do |k,v|
+            stat[k] += v if k.start_with?('peak_', 'last_')
+          end
+        end
+      end
+    end
+
+    if key
+      stat[key]
+    else
+      stat
+    end
+  end
+end
+
 module GC
   def self.run(force)
     start
@@ -76,58 +149,14 @@ def garbage_collect
   end
 
   def self.stat(key = nil)
-    time, count, minor_count, major_count, unknown_count, heap, memory_pool_names, memory_pool_info = Primitive.gc_stat
-    used, committed, init, max = heap
-
-    # Initialize stat for statistics that come from memory pools, and populate it with some final stats (ordering similar to MRI)
-    stat = {
-      count: count,
-      time: time,
-      minor_gc_count: minor_count,
-      major_gc_count: major_count,
-      unknown_count: unknown_count, # if nonzero, major or minor count needs to be updated for this GC case
-      heap_available_slots: committed,
-      heap_live_slots: used,
-      heap_free_slots: committed - used,
-      used: used,
-      committed: committed,
-      init: init,
-      max: max,
-    }
-    stat.default = 0
-
-    unless Primitive.object_kind_of?(key, Symbol) # memory_pool_names are Strings
-      memory_pool_names.each_with_index do |memory_pool_name, i|
-        # Populate memory pool specific stats
-        info = memory_pool_info[i]
-        if info
-          stat[memory_pool_name] = data = {
-            used: info[0],
-            committed: info[1],
-            init: info[2],
-            max: info[3],
-            peak_used: info[4],
-            peak_committed: info[5],
-            peak_init: info[6],
-            peak_max: info[7],
-            last_used: info[8],
-            last_committed: info[9],
-            last_init: info[10],
-            last_max: info[11],
-          }
-
-          # Calculate stats across memory pools for peak_/last_ (we already know the values for current usage)
-          data.each_pair do |k,v|
-            stat[k] += v if k.start_with?('peak_', 'last_')
-          end
-        end
-      end
-    end
-
     if key
-      stat[key]
+      if Truffle::GCOperations::KNOWN_KEYS.include?(key)
+        Truffle::GCOperations.stat_hash(key)
+      else
+        0
+      end
     else
-      stat
+      Truffle::GCOperations.stat_hash
     end
   end