Cache default heap dom sizes once computed to avoid slowing down some…

… workflows Summary: Running a command like ``` lo 'type "Foo" 'exec "bt 'dom" ``` saw a noticeable slowdown with the previous change. Cache the default HeapDomSizes object to avoid recomputing it every time. Differential Revision: D54607644 fbshipit-source-id: bb3aac3fb38d123781a5b1d833798ea35e4eded0
facebookexperimental · Mar 7, 2024 · 83f3bb5 · 83f3bb5
1 parent dd85953
commit 83f3bb5
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Showing 3 changed files with 19 additions and 7 deletions.
diff --git a/Analysis/HeapDom.cs b/Analysis/HeapDom.cs
@@ -16,6 +16,7 @@ public sealed class HeapDom
         readonly int[] m_doms;
         readonly Dictionary<int, List<int>> m_domTree;
         readonly int m_numberOfNonLeafNodes;
+        HeapDomSizes? m_defaultHeapDomSizes;
 
         public HeapDom(IBacktracer backtracer)
         {
@@ -43,6 +44,19 @@ public int GetDominator(int nodeIndex)
             return children;
         }
 
+        public HeapDomSizes DefaultHeapDomSizes
+        {
+            get
+            {
+                if (m_defaultHeapDomSizes == null)
+                {
+                    m_defaultHeapDomSizes = new HeapDomSizes(this, typeSet: null);
+                }
+
+                return m_defaultHeapDomSizes;
+            }
+        }
+
         int[] ComputeDominators()
         {
             // Engineered algorithm from https://www.cs.rice.edu/~keith/EMBED/dom.pdf

diff --git a/CommandInfrastructure/Command.cs b/CommandInfrastructure/Command.cs
@@ -136,17 +136,15 @@ public HeapDom CurrentHeapDom
 
         public HeapDomSizes MakeHeapDomSizes(CommandLineArgument? typeIndexOrPattern, bool includeDerived)
         {
-            TypeSet? typeSet;
             if (typeIndexOrPattern != null)
             {
-                typeSet = typeIndexOrPattern.ResolveTypeIndexOrPattern(Context, includeDerived);
+                TypeSet typeSet = typeIndexOrPattern.ResolveTypeIndexOrPattern(Context, includeDerived);
+                return new HeapDomSizes(CurrentHeapDom, typeSet);
             }
             else
             {
-                typeSet = null;
+                return CurrentHeapDom.DefaultHeapDomSizes;
             }
-
-            return new HeapDomSizes(CurrentHeapDom, typeSet);
         }
 
         public void DescribeAddress(NativeWord addressOfValue, StringBuilder sb)

diff --git a/Commands/ListObjectsCommand.cs b/Commands/ListObjectsCommand.cs
@@ -155,10 +155,10 @@ internal Selection(Context context, SortOrder sortOrder)
                 m_sortOrder = sortOrder;
                 if (m_sortOrder == SortOrder.SortByDomSize)
                 {
-                    // We use a null typeSet here because the existing 'type argument is not what we want.
+                    // We use the default HeapDomSizes here because the existing 'type argument is not what we want.
                     // If we want to support sorting by dominator size for a type-filtered dominator tree,
                     // we can decide to add 'domtype and 'domincludederived arguments.
-                    m_heapDomSizes = new HeapDomSizes(m_context.CurrentHeapDom!, typeSet: null);
+                    m_heapDomSizes = m_context.CurrentHeapDom!.DefaultHeapDomSizes;
                 }
 
                 if (sortOrder == SortOrder.SortByDomSize)