From 82fbf34f5bd5e0d8cd6f46751e910e56d621d49d Mon Sep 17 00:00:00 2001
From: Stenzek <stenzek@gmail.com>
Date: Thu, 23 May 2024 23:41:12 +1000
Subject: [PATCH] ImGuiOverlays: Display vsync queue size in OSD

---
 pcsx2/ImGui/ImGuiOverlays.cpp | 6 ++++--
 pcsx2/MTGS.cpp                | 5 +++++
 pcsx2/MTGS.h                  | 1 +
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/pcsx2/ImGui/ImGuiOverlays.cpp b/pcsx2/ImGui/ImGuiOverlays.cpp
index 4931182a0a..ee17844e65 100644
--- a/pcsx2/ImGui/ImGuiOverlays.cpp
+++ b/pcsx2/ImGui/ImGuiOverlays.cpp
@@ -190,8 +190,10 @@ __ri void ImGuiManager::DrawPerformanceOverlay(float& position_y, float scale, f
 		if (GSConfig.OsdShowCPU)
 		{
 			text.clear();
-			text.append_format("{:.2f}ms | {:.2f}ms | {:.2f}ms", PerformanceMetrics::GetMinimumFrameTime(),
-				PerformanceMetrics::GetAverageFrameTime(), PerformanceMetrics::GetMaximumFrameTime());
+			text.append_format("{} QF | {:.2f}ms | {:.2f}ms | {:.2f}ms",
+				MTGS::GetCurrentVsyncQueueSize() - 1, // we subtract one for the current frame
+				PerformanceMetrics::GetMinimumFrameTime(), PerformanceMetrics::GetAverageFrameTime(),
+				PerformanceMetrics::GetMaximumFrameTime());
 			DRAW_LINE(fixed_font, text.c_str(), IM_COL32(255, 255, 255, 255));
 
 			text.clear();
diff --git a/pcsx2/MTGS.cpp b/pcsx2/MTGS.cpp
index b7579b9e86..0adf798824 100644
--- a/pcsx2/MTGS.cpp
+++ b/pcsx2/MTGS.cpp
@@ -213,6 +213,11 @@ void MTGS::ResetGS(bool hardware_reset)
 		SetEvent();
 }
 
+int MTGS::GetCurrentVsyncQueueSize()
+{
+	return s_QueuedFrameCount.load(std::memory_order_acquire);
+}
+
 struct RingCmdPacket_Vsync
 {
 	u8 regset1[0x0f0];
diff --git a/pcsx2/MTGS.h b/pcsx2/MTGS.h
index 0921f8e310..94f22aa03a 100644
--- a/pcsx2/MTGS.h
+++ b/pcsx2/MTGS.h
@@ -62,6 +62,7 @@ namespace MTGS
 	void WaitForClose();
 	void Freeze(FreezeAction mode, FreezeData& data);
 
+	int GetCurrentVsyncQueueSize();
 	void PostVsyncStart(bool registers_written);
 	void InitAndReadFIFO(u8* mem, u32 qwc);