From e46dd1bd5f18c628a838f17a3f17c067e70d2e63 Mon Sep 17 00:00:00 2001
From: CamilleLaVey <camillelavey99@gmail.com>
Date: Sat, 8 Aug 2026 19:03:46 -0400
Subject: [PATCH] [TEST] Split downloads

---
 src/video_core/buffer_cache/buffer_cache.h | 44 ++++++++++++++++++++--
 1 file changed, 40 insertions(+), 4 deletions(-)

diff --git a/src/video_core/buffer_cache/buffer_cache.h b/src/video_core/buffer_cache/buffer_cache.h
index da86c14500..6ed3daf5f9 100644
--- a/src/video_core/buffer_cache/buffer_cache.h
+++ b/src/video_core/buffer_cache/buffer_cache.h
@@ -602,7 +602,13 @@ void BufferCache<P>::CommitAsyncFlushesHigh() {
         it++;
     }
 
-    boost::container::small_vector<std::pair<BufferCopy, BufferId>, 16> downloads;
+    struct QueuedDownload {
+        BufferCopy copy;
+        BufferId buffer_id;
+        bool written_in_place;
+    };
+
+    boost::container::small_vector<QueuedDownload, 16> downloads;
     u64 total_size_bytes = 0;
     u64 largest_copy = 0;
     for (const Common::RangeSet<DAddr>& range_set : committed_gpu_modified_ranges) {
@@ -618,7 +624,8 @@ void BufferCache<P>::CommitAsyncFlushesHigh() {
                     new_start, new_end - new_start, false,
                     [&](u64 device_addr_out, u64 range_size) {
                         const DAddr buffer_addr = buffer.CpuAddr();
-                        const auto add_download = [&](DAddr start, DAddr end) {
+                        const auto add_download = [&](DAddr start, DAddr end,
+                                                      bool written_in_place) {
                             const u64 new_offset = start - buffer_addr;
                             const u64 new_size = end - start;
                             downloads.push_back({
@@ -628,6 +635,7 @@ void BufferCache<P>::CommitAsyncFlushesHigh() {
                                     .size = new_size,
                                 },
                                 buffer_id,
+                                written_in_place,
                             });
                             // Align up to avoid cache conflicts
                             constexpr u64 align = 64ULL;
@@ -635,9 +643,23 @@ void BufferCache<P>::CommitAsyncFlushesHigh() {
                             total_size_bytes += (new_size + align - 1) & mask;
                             largest_copy = (std::max)(largest_copy, new_size);
                         };
+                        const auto split_by_in_place = [&](DAddr start, DAddr end) {
+                            DAddr cursor = start;
+                            in_place_gpu_written_ranges.ForEachInRange(
+                                start, end - start, [&](DAddr in_start, DAddr in_end) {
+                                    if (cursor < in_start) {
+                                        add_download(cursor, in_start, false);
+                                    }
+                                    add_download(in_start, in_end, true);
+                                    cursor = in_end;
+                                });
+                            if (cursor < end) {
+                                add_download(cursor, end, false);
+                            }
+                        };
 
                         gpu_modified_ranges.ForEachInRange(device_addr_out, range_size,
-                                                           add_download);
+                                                           split_by_in_place);
                     });
             });
         });
@@ -661,9 +683,18 @@ void BufferCache<P>::CommitAsyncFlushesHigh() {
     boost::container::small_vector<u64, 4> window_ids;
     UnifiedWindowGroups groups;
     u64 staging_size_bytes = 0;
-    for (auto& [copy, buffer_id] : downloads) {
+    bool has_in_place_writes = false;
+    for (auto& [copy, buffer_id, written_in_place] : downloads) {
         Buffer& buffer = slot_buffers[buffer_id];
         const DAddr orig_device_addr = buffer.CpuAddr() + copy.src_offset;
+        if (written_in_place) {
+            BufferCopy record{copy};
+            record.src_offset = static_cast<size_t>(orig_device_addr);
+            async_downloads.Add(orig_device_addr, copy.size);
+            batch.unified_copies.push_back(record);
+            has_in_place_writes = true;
+            continue;
+        }
         bool unified = false;
         if constexpr (USE_UNIFIED_MEMORY) {
             if (runtime.HasUnifiedMemory()) {
@@ -718,6 +749,11 @@ void BufferCache<P>::CommitAsyncFlushesHigh() {
             runtime.UnifiedMemoryHostBarrier();
         }
     }
+    if constexpr (USE_UNIFIED_DIRECT_BINDING) {
+        if (has_in_place_writes) {
+            runtime.UnifiedMemoryShaderWriteBarrier();
+        }
+    }
     runtime.PostCopyBarrier();
     pending_downloads.emplace_back(std::move(batch));
     async_buffers.emplace_back(std::move(download_staging));