From 94da1e8a7e876eaae911332e3539ffcfc783cfac Mon Sep 17 00:00:00 2001
From: bunnei <bunneidev@gmail.com>
Date: Tue, 2 Mar 2021 16:57:53 -0800
Subject: video_core: rasterizer_accelerated: Use a flat array instead of
 interval_map for cached pages.

- Uses a fixed 64MB for the cache instead of an ever growing map.
- Slightly faster by using atomics instead of a single mutex for access.
- Thanks for Rodrigo for the idea.
---
 src/video_core/rasterizer_accelerated.h | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

(limited to 'src/video_core/rasterizer_accelerated.h')

diff --git a/src/video_core/rasterizer_accelerated.h b/src/video_core/rasterizer_accelerated.h
index 91866d7dd..9227a4adc 100644
--- a/src/video_core/rasterizer_accelerated.h
+++ b/src/video_core/rasterizer_accelerated.h
@@ -4,9 +4,8 @@
 
 #pragma once
 
-#include <mutex>
-
-#include <boost/icl/interval_map.hpp>
+#include <array>
+#include <atomic>
 
 #include "common/common_types.h"
 #include "video_core/rasterizer_interface.h"
@@ -26,10 +25,24 @@ public:
     void UpdatePagesCachedCount(VAddr addr, u64 size, int delta) override;
 
 private:
-    using CachedPageMap = boost::icl::interval_map<u64, int>;
-    CachedPageMap cached_pages;
-    std::mutex pages_mutex;
+    class CacheEntry final {
+    public:
+        CacheEntry() = default;
+
+        std::atomic_uint8_t& Count(std::size_t page) {
+            return values[page & 7];
+        }
+
+        const std::atomic_uint8_t& Count(std::size_t page) const {
+            return values[page & 7];
+        }
+
+    private:
+        std::array<std::atomic_uint8_t, 8> values{};
+    };
+    static_assert(sizeof(CacheEntry) == 8, "CacheEntry should be 8 bytes!");
 
+    std::array<CacheEntry, 0x800000> cached_pages;
     Core::Memory::Memory& cpu_memory;
 };
 
-- 
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