From 8d1717963b0e9430fa22a52bc8094cc9d147dac7 Mon Sep 17 00:00:00 2001
From: Luigi Rizzo <luigi@FreeBSD.org>
Date: Wed, 25 Jul 2012 11:28:15 +0000
Subject: [PATCH] Use legacy interrupts as a default. This gives up to 10%
 speedup when used in qemu (and this driver is for non-PCIe cards, so probably
 its largest use is in virtualized environments).

Approved by:	Jack Vogel
MFC after:	3 days
---
 sys/dev/e1000/if_lem.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/sys/dev/e1000/if_lem.c b/sys/dev/e1000/if_lem.c
index b5bca6a8e4fb..a5249307fe06 100644
--- a/sys/dev/e1000/if_lem.c
+++ b/sys/dev/e1000/if_lem.c
@@ -239,6 +239,7 @@ static void     lem_enable_wakeup(device_t);
 static int	lem_enable_phy_wakeup(struct adapter *);
 static void	lem_led_func(void *, int);
 
+#define EM_LEGACY_IRQ	/* slightly faster, at least in qemu */
 #ifdef EM_LEGACY_IRQ
 static void	lem_intr(void *);
 #else /* FAST IRQ */
@@ -1549,6 +1550,13 @@ lem_xmit(struct adapter *adapter, struct mbuf **m_headp)
 	u32			txd_upper, txd_lower, txd_used, txd_saved;
 	int			error, nsegs, i, j, first, last = 0;
 
+extern int netmap_drop;
+	if (netmap_drop == 95) {
+dropme:
+			m_freem(*m_headp);
+			*m_headp = NULL;
+			return (ENOBUFS);
+	}
 	m_head = *m_headp;
 	txd_upper = txd_lower = txd_used = txd_saved = 0;
 
@@ -1688,6 +1696,9 @@ lem_xmit(struct adapter *adapter, struct mbuf **m_headp)
 		}
 	}
 
+	if (netmap_drop == 96)
+		goto dropme;
+
 	adapter->next_avail_tx_desc = i;
 
 	if (adapter->pcix_82544)
@@ -1715,6 +1726,16 @@ lem_xmit(struct adapter *adapter, struct mbuf **m_headp)
          */
         ctxd->lower.data |=
 	    htole32(E1000_TXD_CMD_EOP | E1000_TXD_CMD_RS);
+
+if (netmap_drop == 97) {
+	static int count=0;
+	if (count++ & 63 != 0)
+		 ctxd->lower.data &=
+            ~htole32(E1000_TXD_CMD_RS);
+	else
+		D("preserve RS");
+
+}
 	/*
 	 * Keep track in the first buffer which
 	 * descriptor will be written back
@@ -1733,6 +1754,12 @@ lem_xmit(struct adapter *adapter, struct mbuf **m_headp)
 	    adapter->link_duplex == HALF_DUPLEX)
 		lem_82547_move_tail(adapter);
 	else {
+extern int netmap_repeat;
+		if (netmap_repeat) {
+			int x;
+			for (x = 0; x < netmap_repeat; x++)
+				E1000_WRITE_REG(&adapter->hw, E1000_TDT(0), i);
+		}
 		E1000_WRITE_REG(&adapter->hw, E1000_TDT(0), i);
 		if (adapter->hw.mac.type == e1000_82547)
 			lem_82547_update_fifo_head(adapter,
@@ -2986,6 +3013,13 @@ lem_txeof(struct adapter *adapter)
 		return;
 	}
 #endif /* DEV_NETMAP */
+{
+	static int drops = 0;
+	if (netmap_copy && drops++ < netmap_copy)
+		return;
+	drops = 0;
+}
+
         if (adapter->num_tx_desc_avail == adapter->num_tx_desc)
                 return;