From 50b175bcbbd5ce5a8a6586d2738a9b8db8efd334 Mon Sep 17 00:00:00 2001
From: Vladimir Sadov <vsadov@live.com>
Date: Sat, 17 May 2025 12:20:08 -0700
Subject: [PATCH] Report collection counts non-inclusively (#51)

---
 src/coreclr/gc/satori/SatoriGC.cpp | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/coreclr/gc/satori/SatoriGC.cpp b/src/coreclr/gc/satori/SatoriGC.cpp
index 674b46c4b82..bc91fc3b79e 100644
--- a/src/coreclr/gc/satori/SatoriGC.cpp
+++ b/src/coreclr/gc/satori/SatoriGC.cpp
@@ -197,13 +197,26 @@ unsigned SatoriGC::WhichGeneration(Object* obj)
 
 int SatoriGC::CollectionCount(int generation, int get_bgc_fgc_coutn)
 {
-    //get_bgc_fgc_coutn N/A
+    // get_bgc_fgc_coutn - not sure what this is. thus N/A
+
     if ((unsigned)generation > (unsigned)2)
     {
         return 0;
     }
 
-    return (int)m_heap->Recycler()->GetCollectionCount(generation);
+    int64_t count = m_heap->Recycler()->GetCollectionCount(generation);
+
+    // in the public API GC counts are not inclusive
+    if (generation < 1)
+    {
+        count -= m_heap->Recycler()->GetCollectionCount(1);
+    }
+    else if (generation < 2)
+    {
+        count -= m_heap->Recycler()->GetCollectionCount(2);
+    }
+
+    return (int)count;
 }
 
 int SatoriGC::StartNoGCRegion(uint64_t totalSize, bool lohSizeKnown, uint64_t lohSize, bool disallowFullBlockingGC)
@@ -360,6 +373,8 @@ bool SatoriGC::IsGCInProgressHelper(bool bConsiderGCStart)
     return m_gcInProgress;
 }
 
+// this is basically a GC index
+// it is used in suspend events, and in GC stress.
 unsigned SatoriGC::GetGcCount()
 {
     if (!m_heap)
@@ -367,7 +382,7 @@ unsigned SatoriGC::GetGcCount()
         return 0;
     }
 
-    return (unsigned)(int)m_heap->Recycler()->GetCollectionCount(/*gen*/ 1);
+    return (unsigned)(int)m_heap->Recycler()->GetCollectionCount(/*gen*/ 0);
 }
 
 bool SatoriGC::IsThreadUsingAllocationContextHeap(gc_alloc_context* acontext, int thread_number)