From e08b40252790eef96337409d7dd606aa7bfa8428 Mon Sep 17 00:00:00 2001
From: Takoroka <137927095+Takoroka@users.noreply.github.com>
Date: Thu, 29 Oct 2026 01:51:42 -0400
Subject: video_core: less waiting on the GPU caches' locks

- The texture and buffer caches' mutexes spin briefly before sleeping
  (Common::SpinRecursiveMutex): the GPU thread, the fencing thread and
  CPU write traps take them tens of thousands of times a second for
  microseconds, and a sleeping waiter's wake-up took longer than that.
  Title 1's GPU thread slept 7.7% of its time there, now 3.7%.
- Fences commit and pop texture and buffer downloads separately, and
  only when there are any (one fence per compute dispatch in Switch 2
  titles): the fencing thread no longer holds both caches while it
  copies buffer downloads.
- Inline uploads and pre-draw invalidation take the caches one at a
  time again: holding one while std::lock waited for the other waited
  longer.
---
 src/video_core/renderer_vulkan/vk_rasterizer.cpp | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

(limited to 'src/video_core/renderer_vulkan/vk_rasterizer.cpp')

diff --git a/src/video_core/renderer_vulkan/vk_rasterizer.cpp b/src/video_core/renderer_vulkan/vk_rasterizer.cpp
index 886c5dbfe4..429b2d63ef 100644
--- a/src/video_core/renderer_vulkan/vk_rasterizer.cpp
+++ b/src/video_core/renderer_vulkan/vk_rasterizer.cpp
@@ -1036,11 +1036,13 @@ void RasterizerVulkan::InvalidateRegion(DAddr addr, u64 size, VideoCommon::Cache
 
 void RasterizerVulkan::InnerInvalidation(std::span<const std::pair<DAddr, std::size_t>> sequences) {
     {
-        // Both caches under one lock: this runs before most draws (constant buffer updates).
-        std::scoped_lock lock{buffer_cache.mutex, texture_cache.mutex};
+        std::scoped_lock lock{texture_cache.mutex};
         for (const auto& [addr, size] : sequences) {
             texture_cache.WriteMemory(addr, size);
         }
+    }
+    {
+        std::scoped_lock lock{buffer_cache.mutex};
         for (const auto& [addr, size] : sequences) {
             buffer_cache.WriteMemory(addr, size);
         }
@@ -1248,12 +1250,16 @@ void RasterizerVulkan::AccelerateInlineToMemory(GPUVAddr address, size_t copy_si
         return;
     }
     gpu_memory->WriteBlockUnsafe(address, memory.data(), copy_size);
+    // One cache at a time: holding both while waiting for either (std::lock) waited longer, the
+    // fencing thread and CPU write traps holding one of them most of the time.
     {
-        // Both caches under one lock (title 1 makes thousands of inline uploads a second).
-        std::scoped_lock lock{buffer_cache.mutex, texture_cache.mutex};
+        std::scoped_lock lock{buffer_cache.mutex};
         if (!buffer_cache.InlineMemory(*cpu_addr, copy_size, memory)) {
             buffer_cache.WriteMemory(*cpu_addr, copy_size);
         }
+    }
+    {
+        std::scoped_lock lock{texture_cache.mutex};
         texture_cache.WriteMemory(*cpu_addr, copy_size);
     }
     pipeline_cache.InvalidateRegion(*cpu_addr, copy_size);
-- 
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