igb: change descriptor control thresholds

This change simplifies the code by setting RX_PTHRESH to 8 for
all devices, as it was unlikely that there was any advantage to
set it at 16 for earlier cards. Additionally TX_WTHRESH is
set to 1 for the 82576 NIC to improve performance by enabling
a minimal amount of write combining when writing back descriptors.

Signed-off-by: Nicholas Nunley <nicholasx.d.nunley@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Nick Nunley 2010-02-17 01:05:56 +00:00 committed by David S. Miller
parent fe0592b4be
commit 58fd62f525

View File

@ -95,13 +95,13 @@ struct vf_data_storage {
* descriptors until either it has this many to write back, or the * descriptors until either it has this many to write back, or the
* ITR timer expires. * ITR timer expires.
*/ */
#define IGB_RX_PTHRESH (hw->mac.type <= e1000_82576 ? 16 : 8) #define IGB_RX_PTHRESH 8
#define IGB_RX_HTHRESH 8 #define IGB_RX_HTHRESH 8
#define IGB_RX_WTHRESH 1 #define IGB_RX_WTHRESH 1
#define IGB_TX_PTHRESH 8 #define IGB_TX_PTHRESH 8
#define IGB_TX_HTHRESH 1 #define IGB_TX_HTHRESH 1
#define IGB_TX_WTHRESH ((hw->mac.type == e1000_82576 && \ #define IGB_TX_WTHRESH ((hw->mac.type == e1000_82576 && \
adapter->msix_entries) ? 0 : 16) adapter->msix_entries) ? 1 : 16)
/* this is the size past which hardware will drop packets when setting LPE=0 */ /* this is the size past which hardware will drop packets when setting LPE=0 */
#define MAXIMUM_ETHERNET_VLAN_SIZE 1522 #define MAXIMUM_ETHERNET_VLAN_SIZE 1522