[RESEND][PATCH net-drivers-2.6 5/6] e100: Performance optimizations to e100 Tx Path (fwd)

Performance optimizations to e100 Tx Path

Signed-off-by: Mallikarjuna R Chilakala <redacted>
Signed-off-by: Ganesh Venkatesan <redacted>
Signed-off-by: John Ronciak <redacted>
diff -up net-drivers-2.6/drivers/net/e100.c net-drivers-2.6/drivers/net/e100.c.new

--- net-drivers-2.6/drivers/net/e100.c  2005-04-07 03:22:36.805273784 -0700
+++ net-drivers-2.6/drivers/net/e100.c.new      2005-04-07 03:22:37.251205992 -0700

@@ -777,7 +777,7 @@ static int e100_eeprom_save(struct nic *

        return 0;
 }
 
-#define E100_WAIT_SCB_TIMEOUT 40
+#define E100_WAIT_SCB_TIMEOUT 20000 /* we might have to wait 100ms!!! */
 static inline int e100_exec_cmd(struct nic *nic, u8 cmd, dma_addr_t dma_addr)
 {
        unsigned long flags;

@@ -847,6 +847,10 @@ static inline int e100_exec_cb(struct ni

                         * because the controller is too busy, so
                         * let's just queue the command and try again
                         * when another command is scheduled. */
+                       if(err == -ENOSPC) {
+                               //request a reset
+                               schedule_work(&nic->tx_timeout_task);
+                       }
                        break;
                } else {
                        nic->cuc_cmd = cuc_resume;

@@ -891,7 +895,7 @@ static void mdio_write(struct net_device

 
 static void e100_get_defaults(struct nic *nic)
 {
-       struct param_range rfds = { .min = 64, .max = 256, .count = 64 };
+       struct param_range rfds = { .min = 16, .max = 256, .count = 64 };
        struct param_range cbs  = { .min = 64, .max = 256, .count = 64 };
 
        pci_read_config_byte(nic->pdev, PCI_REVISION_ID, &nic->rev_id);

@@ -906,8 +910,9 @@ static void e100_get_defaults(struct nic

        /* Quadwords to DMA into FIFO before starting frame transmit */
        nic->tx_threshold = 0xE0;
 
-       nic->tx_command = cpu_to_le16(cb_tx | cb_i | cb_tx_sf |
-               ((nic->mac >= mac_82558_D101_A4) ? cb_cid : 0));
+       /* no interrupt for every tx completion, delay = 256us if not 557*/
+       nic->tx_command = cpu_to_le16(cb_tx | cb_tx_sf |
+               ((nic->mac >= mac_82558_D101_A4) ? cb_cid : cb_i));
 
        /* Template for a freshly allocated RFD */
        nic->blank_rfd.command = cpu_to_le16(cb_el);

@@ -1289,12 +1294,15 @@ static inline void e100_xmit_prepare(str

        struct sk_buff *skb)
 {
        cb->command = nic->tx_command;
+       /* interrupt every 16 packets regardless of delay */
+       if((nic->cbs_avail & ~15) == nic->cbs_avail) cb->command |= cb_i;
        cb->u.tcb.tbd_array = cb->dma_addr + offsetof(struct cb, u.tcb.tbd);
        cb->u.tcb.tcb_byte_count = 0;
        cb->u.tcb.threshold = nic->tx_threshold;
        cb->u.tcb.tbd_count = 1;
        cb->u.tcb.tbd.buf_addr = cpu_to_le32(pci_map_single(nic->pdev,
                skb->data, skb->len, PCI_DMA_TODEVICE));
+       // check for mapping failure?
        cb->u.tcb.tbd.size = cpu_to_le16(skb->len);
 }