igb: Improve multiqueue AIM support

Improve multiqueue performance
Change itr_val to reflect ITR timer value instead of ints/sec
Cleaned up AIM algorithms in general

Based on work by Mitch Williams

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Mitch Williams <mitch.a.williams@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 11 insertions, 6 deletions

diff --git a/drivers/net/igb/igb_ethtool.c b/drivers/net/igb/igb_ethtool.c
index 7db183093768..11aee1309951 100644
--- a/drivers/net/igb/igb_ethtool.c
+++ b/drivers/net/igb/igb_ethtool.c
@@ -1861,6 +1861,8 @@ static int igb_set_coalesce(struct net_device *netdev,
                             struct ethtool_coalesce *ec)
 {
         struct igb_adapter *adapter = netdev_priv(netdev);
+        struct e1000_hw *hw = &adapter->hw;
+        int i;
 
         if ((ec->rx_coalesce_usecs > IGB_MAX_ITR_USECS) ||
             ((ec->rx_coalesce_usecs > 3) &&
@@ -1869,13 +1871,16 @@ static int igb_set_coalesce(struct net_device *netdev,
                 return -EINVAL;
 
         /* convert to rate of irq's per second */
-        if (ec->rx_coalesce_usecs <= 3)
+        if (ec->rx_coalesce_usecs && ec->rx_coalesce_usecs <= 3) {
                 adapter->itr_setting = ec->rx_coalesce_usecs;
-        else
-                adapter->itr_setting = (1000000 / ec->rx_coalesce_usecs);
+                adapter->itr = IGB_START_ITR;
+        } else {
+                adapter->itr_setting = ec->rx_coalesce_usecs << 2;
+                adapter->itr = adapter->itr_setting;
+        }
 
-        if (netif_running(netdev))
-                igb_reinit_locked(adapter);
+        for (i = 0; i < adapter->num_rx_queues; i++)
+                wr32(adapter->rx_ring[i].itr_register, adapter->itr);
 
         return 0;
 }
@@ -1888,7 +1893,7 @@ static int igb_get_coalesce(struct net_device *netdev,
         if (adapter->itr_setting <= 3)
                 ec->rx_coalesce_usecs = adapter->itr_setting;
         else
-                ec->rx_coalesce_usecs = 1000000 / adapter->itr_setting;
+                ec->rx_coalesce_usecs = adapter->itr_setting >> 2;
 
         return 0;
 }