Merge pull request #505 from unknownbrackets/cso

Small optimization to CSO support, add notes

pcsx2/CDVD/CsoFileReader.cpp

@@ -140,28 +140,44 @@ bool CsoFileReader::InitializeBuffers() {
 		return false;
 	}
 
+	m_z_stream = new z_stream;
+	m_z_stream->zalloc = Z_NULL;
+	m_z_stream->zfree = Z_NULL;
+	m_z_stream->opaque = Z_NULL;
+	if (inflateInit2(m_z_stream, -15) != Z_OK) {
+		Console.Error("Unable to initialize zlib for CSO decompression.");
+		return false;
+	}
+
 	return true;
 }
 
 void CsoFileReader::Close() {
 	m_filename.Empty();
+#if CSO_USE_CHUNKSCACHE
+	m_cache.Clear();
+#endif
 
 	if (m_src) {
 		fclose(m_src);
-		m_src = 0;
+		m_src = NULL;
+	}
+	if (m_z_stream) {
+		inflateEnd(m_z_stream);
+		m_z_stream = NULL;
 	}
 
 	if (m_readBuffer) {
 		delete[] m_readBuffer;
-		m_readBuffer = 0;
+		m_readBuffer = NULL;
 	}
 	if (m_zlibBuffer) {
 		delete[] m_zlibBuffer;
-		m_zlibBuffer = 0;
+		m_zlibBuffer = NULL;
 	}
 	if (m_index) {
 		delete[] m_index;
-		m_index = 0;
+		m_index = NULL;
 	}
 }
 
@@ -170,6 +186,9 @@ int CsoFileReader::ReadSync(void* pBuffer, uint sector, uint count) {
 		return 0;
 	}
 
+	// Note that, in practice, count will always be 1.  It seems one sector is read
+	// per interrupt, even if multiple are requested by the application.
+
 	u8* dest = (u8*)pBuffer;
 	// We do it this way in case m_blocksize is not well aligned to our frame size.
 	u64 pos = (u64)sector * (u64)m_blocksize;
@@ -177,18 +196,37 @@ int CsoFileReader::ReadSync(void* pBuffer, uint sector, uint count) {
 	int bytes = 0;
 
 	while (remaining > 0) {
-		int readBytes = ReadFromFrame(dest + bytes, pos + bytes, remaining);
-		if (readBytes == 0) {
-			// We hit EOF.
-			break;
+		int readBytes;
+
+#if CSO_USE_CHUNKSCACHE
+		// Try first to read from the cache.
+		readBytes = m_cache.Read(dest + bytes, pos + bytes, remaining);
+#else
+		readBytes = -1;
+#endif
+		if (readBytes < 0) {
+			readBytes = ReadFromFrame(dest + bytes, pos + bytes, remaining);
+			if (readBytes == 0) {
+				// We hit EOF.
+				break;
+			}
+
+#if CSO_USE_CHUNKSCACHE
+			// Add the bytes into the cache.  We need to allocate a buffer for it.
+			void *cached = malloc(readBytes);
+			memcpy(cached, dest + bytes, readBytes);
+			m_cache.Take(cached, pos + bytes, readBytes, readBytes);
+#endif
 		}
+
 		bytes += readBytes;
 		remaining -= readBytes;
 	}
+
 	return bytes;
 }
 
-int CsoFileReader::ReadFromFrame(u8 *dest, u64 pos, u64 maxBytes) {
+int CsoFileReader::ReadFromFrame(u8 *dest, u64 pos, int maxBytes) {
 	if (pos >= m_totalSize) {
 		// Can't read anything passed the end.
 		return 0;
@@ -238,41 +276,33 @@ int CsoFileReader::ReadFromFrame(u8 *dest, u64 pos, u64 maxBytes) {
 }
 
 bool CsoFileReader::DecompressFrame(u32 frame, u32 readBufferSize) {
-	z_stream z;
-	z.zalloc = Z_NULL;
-	z.zfree = Z_NULL;
-	z.opaque = Z_NULL;
-	if (inflateInit2(&z, -15) != Z_OK) {
-		Console.Error("Unable to initialize zlib for CSO decompression.");
-		return false;
-	}
+	m_z_stream->next_in = m_readBuffer;
+	m_z_stream->avail_in = readBufferSize;
+	m_z_stream->next_out = m_zlibBuffer;
+	m_z_stream->avail_out = m_frameSize;
 
-	z.next_in = m_readBuffer;
-	z.avail_in = readBufferSize;
-	z.next_out = m_zlibBuffer;
-	z.avail_out = m_frameSize;
-
-	int status = inflate(&z, Z_FINISH);
-	if (status != Z_STREAM_END || z.total_out != m_frameSize) {
-		inflateEnd(&z);
+	int status = inflate(m_z_stream, Z_FINISH);
+	bool success = status == Z_STREAM_END && m_z_stream->total_out == m_frameSize;
+	if (success) {
+		// Our buffer now contains this frame.
+		m_zlibBufferFrame = frame;
+	} else {
 		Console.Error("Unable to decompress CSO frame using zlib.");
-		return false;
+		m_zlibBufferFrame = (u32)-1;
 	}
-	inflateEnd(&z);
 
-	// Our buffer now contains this frame.
-	m_zlibBufferFrame = frame;
-	return true;
+	inflateReset(m_z_stream);
+	return success;
 }
 
 void CsoFileReader::BeginRead(void* pBuffer, uint sector, uint count) {
 	// TODO: No async support yet, implement as sync.
-	mBytesRead = ReadSync(pBuffer, sector, count);
+	m_bytesRead = ReadSync(pBuffer, sector, count);
 }
 
 int CsoFileReader::FinishRead() {
-	int res = mBytesRead;
-	mBytesRead = -1;
+	int res = m_bytesRead;
+	m_bytesRead = -1;
 	return res;
 }
 

pcsx2/CDVD/CsoFileReader.h

@@ -15,9 +15,22 @@
 
 #pragma once
 
+// Based on testing, the overhead of using this cache is high.
+//
+// The test was done with CSO files using a block size of 16KB.
+// Cache hit rates were observed in the range of 25%.
+// Cache overhead added 35% to the overall read time.
+//
+// For this reason, it's currently disabled.
+#define CSO_USE_CHUNKSCACHE 0
+
 #include "AsyncFileReader.h"
+#include "ChunksCache.h"
 
 struct CsoHeader;
+typedef struct z_stream_s z_stream;
+
+static const uint CSO_CHUNKCACHE_SIZE_MB = 200;
 
 class CsoFileReader : public AsyncFileReader
 {
@@ -28,7 +41,12 @@ public:
 		m_zlibBuffer(0),
 		m_index(0),
 		m_totalSize(0),
-		m_src(0) {
+		m_src(0),
+		m_z_stream(0),
+#if CSO_USE_CHUNKSCACHE
+		m_cache(CSO_CHUNKCACHE_SIZE_MB),
+#endif
+		m_bytesRead(0) {
 		m_blocksize = 2048;
 	};
 
@@ -56,7 +74,7 @@ private:
 	static bool ValidateHeader(const CsoHeader& hdr);
 	bool ReadFileHeader();
 	bool InitializeBuffers();
-	int ReadFromFrame(u8 *dest, u64 pos, u64 maxBytes);
+	int ReadFromFrame(u8 *dest, u64 pos, int maxBytes);
 	bool DecompressFrame(u32 frame, u32 readBufferSize);
 
 	u32 m_frameSize;
@@ -69,6 +87,12 @@ private:
 	u64 m_totalSize;
 	// The actual source cso file handle.
 	FILE* m_src;
+	z_stream* m_z_stream;
+
+#if CSO_USE_CHUNKSCACHE
+	ChunksCache m_cache;
+#endif
+
 	// The result of a read is stored here between BeginRead() and FinishRead().
-	int mBytesRead;
+	int m_bytesRead;
 };