svn commit: r238765 - head/sys/dev/e1000

[Luigi Rizzo]

Author: luigi
Date: Wed Jul 25 11:28:15 2012
New Revision: 238765
URL: http://svn.freebsd.org/changeset/base/238765

Log:
  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

Modified:
  head/sys/dev/e1000/if_lem.c

Modified: head/sys/dev/e1000/if_lem.c
==============================================================================
--- head/sys/dev/e1000/if_lem.c Wed Jul 25 10:55:14 2012        (r238764)
+++ head/sys/dev/e1000/if_lem.c Wed Jul 25 11:28:15 2012        (r238765)
@@ -239,6 +239,7 @@ static void     lem_enable_wakeup(device
 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
        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
                }
        }
 
+       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
          */
         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
            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;
 
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