Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=906674abab0424b466a2db4bb6a890a8c477b10a
Commit:     906674abab0424b466a2db4bb6a890a8c477b10a
Parent:     61cec3bddc79373a246e2f8eb13e5acdc106f46a
Author:     Olof Johansson <[EMAIL PROTECTED]>
AuthorDate: Wed Nov 28 20:57:09 2007 -0600
Committer:  David S. Miller <[EMAIL PROTECTED]>
CommitDate: Mon Jan 28 15:04:24 2008 -0800

    pasemi_mac: Improve RX interrupt mitigation
    
    pasemi_mac: Improve RX interrupt mitigation
    
    Currently the receive side interrupts will go off on the reception of
    a packet, NAPI will poll the ring and keep polling as long as there's
    a decent amount of packets to receive.
    
    This is less than optimal, especially for LRO where it's better if we
    have a more substantial amount of packets to process at once, to get
    the real LRO benefits.
    
    So, set the count threshold to a higher value and use the timeout feature
    that will give us an interrupt even if not enough packets have come in
    to set off the count threshold.
    
    FIXME: It'd be real nice to have ethtool support for users to tune this
    at runtime.
    
    Signed-off-by: Olof Johansson <[EMAIL PROTECTED]>
    Signed-off-by: Jeff Garzik <[EMAIL PROTECTED]>
---
 drivers/net/pasemi_mac.c |   18 ++++++++++--------
 1 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/net/pasemi_mac.c b/drivers/net/pasemi_mac.c
index 683e8de..e78aac4 100644
--- a/drivers/net/pasemi_mac.c
+++ b/drivers/net/pasemi_mac.c
@@ -504,15 +504,19 @@ static void pasemi_mac_replenish_rx_ring(const struct 
net_device *dev,
 
 static void pasemi_mac_restart_rx_intr(const struct pasemi_mac *mac)
 {
+       struct pasemi_mac_rxring *rx = rx_ring(mac);
        unsigned int reg, pcnt;
        /* Re-enable packet count interrupts: finally
         * ack the packet count interrupt we got in rx_intr.
         */
 
-       pcnt = *rx_ring(mac)->chan.status & PAS_STATUS_PCNT_M;
+       pcnt = *rx->chan.status & PAS_STATUS_PCNT_M;
 
        reg = PAS_IOB_DMA_RXCH_RESET_PCNT(pcnt) | PAS_IOB_DMA_RXCH_RESET_PINTC;
 
+       if (*rx->chan.status & PAS_STATUS_TIMER)
+               reg |= PAS_IOB_DMA_RXCH_RESET_TINTC;
+
        write_iob_reg(PAS_IOB_DMA_RXCH_RESET(mac->rx->chan.chno), reg);
 }
 
@@ -795,8 +799,6 @@ static irqreturn_t pasemi_mac_rx_intr(int irq, void *data)
                reg |= PAS_IOB_DMA_RXCH_RESET_SINTC;
        if (*chan->status & PAS_STATUS_ERROR)
                reg |= PAS_IOB_DMA_RXCH_RESET_DINTC;
-       if (*chan->status & PAS_STATUS_TIMER)
-               reg |= PAS_IOB_DMA_RXCH_RESET_TINTC;
 
        netif_rx_schedule(dev, &mac->napi);
 
@@ -972,10 +974,6 @@ static int pasemi_mac_open(struct net_device *dev)
 
        write_mac_reg(mac, PAS_MAC_CFG_TXP, flags);
 
-       /* 0xffffff is max value, about 16ms */
-       write_iob_reg(PAS_IOB_DMA_COM_TIMEOUTCFG,
-                     PAS_IOB_DMA_COM_TIMEOUTCFG_TCNT(0xffffff));
-
        ret = pasemi_mac_setup_rx_resources(dev);
        if (ret)
                goto out_rx_resources;
@@ -985,8 +983,12 @@ static int pasemi_mac_open(struct net_device *dev)
        if (!mac->tx)
                goto out_tx_ring;
 
+       /* 0x3ff with 33MHz clock is about 31us */
+       write_iob_reg(PAS_IOB_DMA_COM_TIMEOUTCFG,
+                     PAS_IOB_DMA_COM_TIMEOUTCFG_TCNT(0x3ff));
+
        write_iob_reg(PAS_IOB_DMA_RXCH_CFG(mac->rx->chan.chno),
-                     PAS_IOB_DMA_RXCH_CFG_CNTTH(0));
+                     PAS_IOB_DMA_RXCH_CFG_CNTTH(128));
 
        write_iob_reg(PAS_IOB_DMA_TXCH_CFG(mac->tx->chan.chno),
                      PAS_IOB_DMA_TXCH_CFG_CNTTH(32));
-
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