From 9e3873d1df10f780b0bf1d2c1f4e35ce27a27980 Mon Sep 17 00:00:00 2001
From: ergo720 <45463469+ergo720@users.noreply.github.com>
Date: Sun, 12 Mar 2023 16:51:38 +0100
Subject: [PATCH] Place nvnet in its own thread

---
 src/common/Timer.cpp                |  3 ---
 src/devices/network/NVNetDevice.cpp | 16 ++++++++++++----
 src/devices/network/NVNetDevice.h   |  2 --
 3 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/src/common/Timer.cpp b/src/common/Timer.cpp
index b605654a9..969308279 100644
--- a/src/common/Timer.cpp
+++ b/src/common/Timer.cpp
@@ -115,9 +115,6 @@ static void update_non_periodic_events()
 	// update dsound
 	dsound_worker();
 
-	// check nvnet
-	NVNetRecv();
-
 	// check for hw interrupts, but skip the gpu interrupt since that is serviced in vblank_next
 	for (int i = 0; i < 3; i++) {
 		// If the interrupt is pending and connected, process it
diff --git a/src/devices/network/NVNetDevice.cpp b/src/devices/network/NVNetDevice.cpp
index 72e405c22..8b6b62740 100644
--- a/src/devices/network/NVNetDevice.cpp
+++ b/src/devices/network/NVNetDevice.cpp
@@ -475,12 +475,19 @@ void EmuNVNet_Write(xbox::addr_xt addr, uint32_t value, int size)
 	EmuLog(LOG_LEVEL::DEBUG, "Write%d: %s (0x%.8X) = 0x%.8X", size * 8, EmuNVNet_GetRegisterName(addr), addr, value);
 }
 
-void NVNetRecv()
+std::thread NVNetRecvThread;
+void NVNetRecvThreadProc()
 {
+	// NOTE: profiling shows that the winpcap function can take up to 1/6th of the total cpu time of the loader process, so avoid placing
+	// this function in system_events
+	g_AffinityPolicy->SetAffinityOther();
 	static std::unique_ptr<uint8_t[]> packet(new uint8_t[65536]);
-	int size = g_NVNet->PCAPReceive(packet.get(), 65536);
-	if (size > 0) {
-		EmuNVNet_DMAPacketToGuest(packet.get(), size);
+	while (true) {
+		int size = g_NVNet->PCAPReceive(packet.get(), 65536);
+		if (size > 0) {
+			EmuNVNet_DMAPacketToGuest(packet.get(), size);
+		}
+		_mm_pause();
 	}
 }
 
@@ -523,6 +530,7 @@ void NVNetDevice::Init()
 	};
 
 	PCAPInit();
+	NVNetRecvThread = std::thread(NVNetRecvThreadProc);
 }
 
 void NVNetDevice::Reset()
diff --git a/src/devices/network/NVNetDevice.h b/src/devices/network/NVNetDevice.h
index f7a1c3e97..d2a069396 100644
--- a/src/devices/network/NVNetDevice.h
+++ b/src/devices/network/NVNetDevice.h
@@ -229,5 +229,3 @@ private:
 	mac_address m_GuestMacAddress = { 0x00, 0x50, 0xF2, 0x00, 0x00, 0x34 };
 	mac_address m_BroadcastMacAddress = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
 };
-
-void NVNetRecv();