Adds support for PE performance metrics in the D3D9 backend

Source/Plugins/Plugin_VideoDX9/Src/PerfQuery.h

@@ -0,0 +1,46 @@
+#ifndef _PERFQUERY_H_
+#define _PERFQUERY_H_
+
+#include "PerfQueryBase.h"
+
+namespace DX9 {
+
+class PerfQuery : public PerfQueryBase
+{
+public:
+	PerfQuery();
+	~PerfQuery();
+
+	void EnableQuery(PerfQueryGroup type);
+	void DisableQuery(PerfQueryGroup type);
+	void ResetQuery();
+	u32 GetQueryResult(PerfQueryType type);
+	void FlushResults();
+	bool IsFlushed() const;
+
+private:
+	struct ActiveQuery
+	{
+		IDirect3DQuery9* query;
+		PerfQueryGroup query_type;
+	};
+
+	void WeakFlush();
+
+	// Only use when non-empty
+	void FlushOne();
+
+	// when testing in SMS: 64 was too small, 128 was ok
+	static const int PERF_QUERY_BUFFER_SIZE = 512;
+
+	ActiveQuery m_query_buffer[PERF_QUERY_BUFFER_SIZE];
+	int m_query_read_pos;
+
+	// TODO: sloppy
+	volatile int m_query_count;
+	volatile u32 m_results[PQG_NUM_MEMBERS];
+};
+
+} // namespace
+
+#endif // _PERFQUERY_H_