From b4c065a0b018848399137ee4d1673cbe7f3fbff4 Mon Sep 17 00:00:00 2001
From: ParantezTech <12572227+par274@users.noreply.github.com>
Date: Mon, 28 Sep 2026 04:37:46 +0300
Subject: [PATCH] [GPU] performance: negative interval filter

---
 .../Gpu/Images/GuestImageCache.Tracking.cs    |  2 +-
 .../Gpu/Images/ImagePageOwnerTable.cs         | 24 ++++++++++++++++++-
 .../Gpu/Images/ImagePageOwnerTableTests.cs    | 13 ++++++++++
 3 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/src/SharpEmu.Libs/Gpu/Images/GuestImageCache.Tracking.cs b/src/SharpEmu.Libs/Gpu/Images/GuestImageCache.Tracking.cs
index a4a4541..f44ace5 100644
--- a/src/SharpEmu.Libs/Gpu/Images/GuestImageCache.Tracking.cs
+++ b/src/SharpEmu.Libs/Gpu/Images/GuestImageCache.Tracking.cs
@@ -363,7 +363,7 @@ public sealed partial class GuestImageCache
     bool IGuestImageStore.MarkCpuWrite(ulong address, ulong size)
     {
         GpuMemoryAccessProfile.CountImageCpuWrite();
-        if (!IsValidRange(address, size))
+        if (!IsValidRange(address, size) || !_pageOwners.MayHaveOwners(address, size))
         {
             return false;
         }
diff --git a/src/SharpEmu.Libs/Gpu/Images/ImagePageOwnerTable.cs b/src/SharpEmu.Libs/Gpu/Images/ImagePageOwnerTable.cs
index 96e1606..455a626 100644
--- a/src/SharpEmu.Libs/Gpu/Images/ImagePageOwnerTable.cs
+++ b/src/SharpEmu.Libs/Gpu/Images/ImagePageOwnerTable.cs
@@ -107,6 +107,7 @@ public sealed class ImagePageOwnerTable
     public const ulong AddressSpaceSize = 1UL << AddressSpaceBits;
 
     private readonly PageOwnerList?[]?[] _firstLevel = new PageOwnerList?[]?[1 << FirstLevelBits];
+    private readonly long[] _everOwnedPages = new long[PageCount / 64];
 
     public int AllocatedBucketCount { get; private set; }
 
@@ -129,7 +130,28 @@ public sealed class ImagePageOwnerTable
             AllocatedBucketCount++;
         }
 
-        return bucket[page & (BucketEntries - 1)] ??= new PageOwnerList();
+        var owners = bucket[page & (BucketEntries - 1)] ??= new PageOwnerList();
+        Interlocked.Or(ref _everOwnedPages[page / 64], 1L << (int)(page % 64));
+        return owners;
+    }
+
+    // Bits are never cleared: a false result can safely bypass the image-cache lock.
+    public bool MayHaveOwners(ulong address, ulong size)
+    {
+        if (!TryGetPageRange(address, size, out var first, out var lastExclusive))
+        {
+            return false;
+        }
+
+        for (var page = first; page < lastExclusive; page++)
+        {
+            if ((Volatile.Read(ref _everOwnedPages[page / 64]) & (1L << (int)(page % 64))) != 0)
+            {
+                return true;
+            }
+        }
+
+        return false;
     }
 
     // The half-open page interval of a non-empty byte range inside the address space.
diff --git a/tests/SharpEmu.Libs.Tests/Gpu/Images/ImagePageOwnerTableTests.cs b/tests/SharpEmu.Libs.Tests/Gpu/Images/ImagePageOwnerTableTests.cs
index 03a3e48..a166666 100644
--- a/tests/SharpEmu.Libs.Tests/Gpu/Images/ImagePageOwnerTableTests.cs
+++ b/tests/SharpEmu.Libs.Tests/Gpu/Images/ImagePageOwnerTableTests.cs
@@ -11,6 +11,19 @@ namespace SharpEmu.Libs.Tests.Gpu.Images;
 [Collection(SchedulingStateCollection.Name)]
 public sealed class ImagePageOwnerTableTests
 {
+    [Fact]
+    public void OwnerSummaryRejectsOnlyPagesThatNeverHadAnOwner()
+    {
+        var table = new ImagePageOwnerTable();
+        var page = ImagePageOwnerTable.BucketEntries;
+        var address = (ulong)page << ImagePageOwnerTable.PageBits;
+        Assert.False(table.MayHaveOwners(address, 4));
+        table.GetOrCreate((ulong)page).Add(Owner(1));
+        Assert.True(table.MayHaveOwners(address, 4));
+        Assert.True(table.MayHaveOwners(address - 4, 8));
+        Assert.False(table.MayHaveOwners(address - 4, 4));
+    }
+
     private static ResourceSlotIdentifier Owner(uint index) => new(index, 1);
 
     [Fact]