From 37829802f5cc049148fe9ae78c67d6313d716fd8 Mon Sep 17 00:00:00 2001
From: Alex Peck <alexpeck@microsoft.com>
Date: Thu, 9 May 2024 10:45:32 -0700
Subject: [PATCH] dump lru item size

---
 .../Lru/LruItemMemoryLayoutDumps.cs           | 68 +++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 BitFaster.Caching.UnitTests/Lru/LruItemMemoryLayoutDumps.cs

diff --git a/BitFaster.Caching.UnitTests/Lru/LruItemMemoryLayoutDumps.cs b/BitFaster.Caching.UnitTests/Lru/LruItemMemoryLayoutDumps.cs
new file mode 100644
index 00000000..b80ddc45
--- /dev/null
+++ b/BitFaster.Caching.UnitTests/Lru/LruItemMemoryLayoutDumps.cs
@@ -0,0 +1,68 @@
+using System;
+using BitFaster.Caching.Lru;
+using ObjectLayoutInspector;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace BitFaster.Caching.UnitTests.Lru
+{
+    public class LruItemMemoryLayoutDumps
+    {
+        private readonly ITestOutputHelper testOutputHelper;
+
+        public LruItemMemoryLayoutDumps(ITestOutputHelper testOutputHelper)
+        {
+            this.testOutputHelper = testOutputHelper;
+        }
+
+        //Type layout for 'LruItem`2'
+        //Size: 24 bytes.Paddings: 6 bytes(%25 of empty space)
+        //|===============================================|
+        //| Object Header(8 bytes)                        |
+        //|-----------------------------------------------|
+        //| Method Table Ptr(8 bytes)                     |
+        //|===============================================|
+        //|   0-7: Object Key(8 bytes)                    |
+        //|-----------------------------------------------|
+        //|  8-15: Object<Value> k__BackingField(8 bytes) |
+        //|-----------------------------------------------|
+        //|    16: Boolean wasAccessed(1 byte)            |
+        //|-----------------------------------------------|
+        //|    17: Boolean wasRemoved(1 byte)             |
+        //|-----------------------------------------------|
+        //| 18-23: padding(6 bytes)                       |
+        //|===============================================|
+        [Fact]
+        public void DumpLruItem()
+        { 
+            var layout = TypeLayout.GetLayout<LruItem<object, object>>(includePaddings: true);
+            testOutputHelper.WriteLine(layout.ToString());
+        }
+
+        //Type layout for 'LongTickCountLruItem`2'
+        //Size: 32 bytes.Paddings: 6 bytes(%18 of empty space)
+        //|==================================================|
+        //| Object Header(8 bytes)                           |
+        //|--------------------------------------------------|
+        //| Method Table Ptr(8 bytes)                        |
+        //|==================================================|
+        //|   0-7: Object Key(8 bytes)                       |
+        //|--------------------------------------------------|
+        //|  8-15: Object<Value> k__BackingField(8 bytes)    |
+        //|--------------------------------------------------|
+        //|    16: Boolean wasAccessed(1 byte)               |
+        //|--------------------------------------------------|
+        //|    17: Boolean wasRemoved(1 byte)                |
+        //|--------------------------------------------------|
+        //| 18-23: padding(6 bytes)                          |
+        //|--------------------------------------------------|
+        //| 24-31: Int64<TickCount> k__BackingField(8 bytes) |
+        //|==================================================|
+        [Fact]
+        public void DumpLongTickCountLruItem()
+        {
+            var layout = TypeLayout.GetLayout<LongTickCountLruItem<object, object>>(includePaddings: true);
+            testOutputHelper.WriteLine(layout.ToString());
+        }
+    }
+}