From 906674abab0424b466a2db4bb6a890a8c477b10a Mon Sep 17 00:00:00 2001 From: Olof Johansson Date: Wed, 28 Nov 2007 20:57:09 -0600 Subject: 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 Signed-off-by: Jeff Garzik --- drivers/net/pasemi_mac.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) (limited to 'drivers/net/pasemi_mac.c') diff --git a/drivers/net/pasemi_mac.c b/drivers/net/pasemi_mac.c index 683e8de0ac89..e78aac488f3c 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)); -- cgit v1.2.3-58-ga151