move the decision to delay raw memcard flushes out of the thread.

This allows the flush to work better with games which hammer
memcard accesses over short periods as it delays more of the work.

Source/Core/Core/HW/GCMemcardRaw.cpp

@@ -12,6 +12,8 @@
 #define SIZE_TO_Mb (1024 * 8 * 16)
 #define MC_HDR_SIZE 0xA000
 
+const std::chrono::seconds MemoryCard::s_flush_interval{ 15 };
+
 MemoryCard::MemoryCard(std::string filename, int _card_index, u16 sizeMb)
 	: MemoryCardBase(_card_index, sizeMb)
 	, m_filename(filename)
@@ -44,6 +46,7 @@ MemoryCard::MemoryCard(std::string filename, int _card_index, u16 sizeMb)
 
 	// Class members (including inherited ones) have now been initialized, so
 	// it's safe to startup the flush thread (which reads them).
+	m_last_flush = std::chrono::steady_clock::now();
 	m_flush_buffer = std::make_unique<u8[]>(memory_card_size);
 	m_flush_thread = std::thread(&MemoryCard::FlushThread, this);
 }
@@ -75,29 +78,10 @@ void MemoryCard::FlushThread()
 	Common::SetCurrentThreadName(
 		StringFromFormat("Memcard%x-Flush", card_index).c_str());
 
-	const auto flush_interval = std::chrono::seconds(15);
-	auto last_flush = std::chrono::steady_clock::now();
-	bool dirty = false;
-
 	for (;;)
 	{
-		bool triggered = m_flush_trigger.WaitFor(flush_interval);
+		m_flush_trigger.Wait();
 		bool do_exit = m_is_exiting.IsSet();
-		if (triggered)
-		{
-			dirty = true;
-		}
-		// Delay the flush if we're not exiting or if the event timed out and
-		// the state isn't dirty.
-		if (!do_exit)
-		{
-			auto now = std::chrono::steady_clock::now();
-			if (now - last_flush < flush_interval || !dirty)
-			{
-				continue;
-			}
-			last_flush = now;
-		}
 
 		// Opening the file is purposefully done each iteration to ensure the
 		// file doesn't disappear out from under us after the first check.
@@ -134,8 +118,6 @@ void MemoryCard::FlushThread()
 			pFile.WriteBytes(&m_flush_buffer[0], memory_card_size);
 		}
 
-		dirty = false;
-
 		if (!do_exit)
 		{
 			Core::DisplayMessage(
@@ -156,6 +138,13 @@ void MemoryCard::FlushThread()
 // be done now.
 void MemoryCard::TryFlush()
 {
+	auto now = std::chrono::steady_clock::now();
+	if (now - m_last_flush < s_flush_interval)
+	{
+		return;
+	}
+	m_last_flush = now;
+
 	if (m_flush_mutex.try_lock())
 	{
 		memcpy(&m_flush_buffer[0], &m_memcard_data[0], memory_card_size);

Source/Core/Core/HW/GCMemcardRaw.h

@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <chrono>
 #include <memory>
 #include "Common/Event.h"
 #include "Common/Flag.h"
@@ -34,4 +35,6 @@ private:
 	Common::Event m_flush_trigger;
 	Common::Flag m_is_exiting;
 	std::unique_ptr<u8[]> m_flush_buffer;
+	std::chrono::steady_clock::time_point m_last_flush;
+	static const std::chrono::seconds s_flush_interval;
 };