[PATCH] e1000: Fix PBA allocation calculations
Bruce Allan [Fri, 15 Dec 2006 09:39:45 +0000 (10:39 +0100)]
Assign the PBA to be large enough to contain at least 2 jumbo frames on
all adapters. This dramatically increases performance on several adapters
and fixes TX performance degradation issues where the PBA was misallocated
in the old algorithm.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/e1000/e1000_hw.h
drivers/net/e1000/e1000_main.c

index f4d01e1..15b8625 100644 (file)
@@ -2422,6 +2422,7 @@ struct e1000_host_command_info {
 #define E1000_PBA_8K 0x0008    /* 8KB, default Rx allocation */
 #define E1000_PBA_12K 0x000C    /* 12KB, default Rx allocation */
 #define E1000_PBA_16K 0x0010    /* 16KB, default TX allocation */
+#define E1000_PBA_20K 0x0014
 #define E1000_PBA_22K 0x0016
 #define E1000_PBA_24K 0x0018
 #define E1000_PBA_30K 0x001E
index e04f1ba..6c3618d 100644 (file)
@@ -661,16 +661,34 @@ e1000_reinit_locked(struct e1000_adapter *adapter)
 void
 e1000_reset(struct e1000_adapter *adapter)
 {
-       uint32_t pba;
+       uint32_t pba = 0, tx_space, min_tx_space, min_rx_space;
        uint16_t fc_high_water_mark = E1000_FC_HIGH_DIFF;
+       boolean_t legacy_pba_adjust = FALSE;
 
        /* Repartition Pba for greater than 9k mtu
         * To take effect CTRL.RST is required.
         */
 
        switch (adapter->hw.mac_type) {
+       case e1000_82542_rev2_0:
+       case e1000_82542_rev2_1:
+       case e1000_82543:
+       case e1000_82544:
+       case e1000_82540:
+       case e1000_82541:
+       case e1000_82541_rev_2:
+               legacy_pba_adjust = TRUE;
+               pba = E1000_PBA_48K;
+               break;
+       case e1000_82545:
+       case e1000_82545_rev_3:
+       case e1000_82546:
+       case e1000_82546_rev_3:
+               pba = E1000_PBA_48K;
+               break;
        case e1000_82547:
        case e1000_82547_rev_2:
+               legacy_pba_adjust = TRUE;
                pba = E1000_PBA_30K;
                break;
        case e1000_82571:
@@ -679,27 +697,80 @@ e1000_reset(struct e1000_adapter *adapter)
                pba = E1000_PBA_38K;
                break;
        case e1000_82573:
-               pba = E1000_PBA_12K;
+               pba = E1000_PBA_20K;
                break;
        case e1000_ich8lan:
                pba = E1000_PBA_8K;
-               break;
-       default:
-               pba = E1000_PBA_48K;
+       case e1000_undefined:
+       case e1000_num_macs:
                break;
        }
 
-       if ((adapter->hw.mac_type != e1000_82573) &&
-          (adapter->netdev->mtu > E1000_RXBUFFER_8192))
-               pba -= 8; /* allocate more FIFO for Tx */
+       if (legacy_pba_adjust == TRUE) {
+               if (adapter->netdev->mtu > E1000_RXBUFFER_8192)
+                       pba -= 8; /* allocate more FIFO for Tx */
 
+               if (adapter->hw.mac_type == e1000_82547) {
+                       adapter->tx_fifo_head = 0;
+                       adapter->tx_head_addr = pba << E1000_TX_HEAD_ADDR_SHIFT;
+                       adapter->tx_fifo_size =
+                               (E1000_PBA_40K - pba) << E1000_PBA_BYTES_SHIFT;
+                       atomic_set(&adapter->tx_fifo_stall, 0);
+               }
+       } else if (adapter->hw.max_frame_size > MAXIMUM_ETHERNET_FRAME_SIZE) {
+               /* adjust PBA for jumbo frames */
+               E1000_WRITE_REG(&adapter->hw, PBA, pba);
+
+               /* To maintain wire speed transmits, the Tx FIFO should be
+                * large enough to accomodate two full transmit packets,
+                * rounded up to the next 1KB and expressed in KB.  Likewise,
+                * the Rx FIFO should be large enough to accomodate at least
+                * one full receive packet and is similarly rounded up and
+                * expressed in KB. */
+               pba = E1000_READ_REG(&adapter->hw, PBA);
+               /* upper 16 bits has Tx packet buffer allocation size in KB */
+               tx_space = pba >> 16;
+               /* lower 16 bits has Rx packet buffer allocation size in KB */
+               pba &= 0xffff;
+               /* don't include ethernet FCS because hardware appends/strips */
+               min_rx_space = adapter->netdev->mtu + ENET_HEADER_SIZE +
+                              VLAN_TAG_SIZE;
+               min_tx_space = min_rx_space;
+               min_tx_space *= 2;
+               E1000_ROUNDUP(min_tx_space, 1024);
+               min_tx_space >>= 10;
+               E1000_ROUNDUP(min_rx_space, 1024);
+               min_rx_space >>= 10;
+
+               /* If current Tx allocation is less than the min Tx FIFO size,
+                * and the min Tx FIFO size is less than the current Rx FIFO
+                * allocation, take space away from current Rx allocation */
+               if (tx_space < min_tx_space &&
+                   ((min_tx_space - tx_space) < pba)) {
+                       pba = pba - (min_tx_space - tx_space);
+
+                       /* PCI/PCIx hardware has PBA alignment constraints */
+                       switch (adapter->hw.mac_type) {
+                       case e1000_82545 ... e1000_82546_rev_3:
+                               pba &= ~(E1000_PBA_8K - 1);
+                               break;
+                       default:
+                               break;
+                       }
 
-       if (adapter->hw.mac_type == e1000_82547) {
-               adapter->tx_fifo_head = 0;
-               adapter->tx_head_addr = pba << E1000_TX_HEAD_ADDR_SHIFT;
-               adapter->tx_fifo_size =
-                       (E1000_PBA_40K - pba) << E1000_PBA_BYTES_SHIFT;
-               atomic_set(&adapter->tx_fifo_stall, 0);
+                       /* if short on rx space, rx wins and must trump tx
+                        * adjustment or use Early Receive if available */
+                       if (pba < min_rx_space) {
+                               switch (adapter->hw.mac_type) {
+                               case e1000_82573:
+                                       /* ERT enabled in e1000_configure_rx */
+                                       break;
+                               default:
+                                       pba = min_rx_space;
+                                       break;
+                               }
+                       }
+               }
        }
 
        E1000_WRITE_REG(&adapter->hw, PBA, pba);