Commit 3de00b89 authored by Stephen Hemminger's avatar Stephen Hemminger Committed by Jeff Garzik
Browse files

chelsio: NAPI speed improvement 



Speedup and cleanup the receive processing by eliminating the
mmio read and a lock round trip.

Signed-off-by: default avatarStephen Hemminger <shemminger@osdl.org>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 4d22de3e

drivers/net/chelsio/sge.c

+35 −42
Original line number Diff line number Diff line
@@ -1559,6 +1559,14 @@ static int process_responses(struct adapter *adapter, int budget) 
	return budget;

}



static inline int responses_pending(const struct adapter *adapter)

{

	const struct respQ *Q = &adapter->sge->respQ;

	const struct respQ_e *e = &Q->entries[Q->cidx];



	return (e->GenerationBit == Q->genbit);

}



#ifdef CONFIG_CHELSIO_T1_NAPI

/*

 * A simpler version of process_responses() that handles only pure (i.e.,
@@ -1568,13 +1576,16 @@ static int process_responses(struct adapter *adapter, int budget) 
 * which the caller must ensure is a valid pure response.  Returns 1 if it

 * encounters a valid data-carrying response, 0 otherwise.

 */

static int process_pure_responses(struct adapter *adapter, struct respQ_e *e)

static int process_pure_responses(struct adapter *adapter)

{

	struct sge *sge = adapter->sge;

	struct respQ *q = &sge->respQ;

	struct respQ_e *e = &q->entries[q->cidx];

	unsigned int flags = 0;

	unsigned int cmdq_processed[SGE_CMDQ_N] = {0, 0};



	if (e->DataValid)

		return 1;

	do {

		flags |= e->Qsleeping;
@@ -1610,23 +1621,20 @@ static int process_pure_responses(struct adapter *adapter, struct respQ_e *e) 
int t1_poll(struct net_device *dev, int *budget)

{

	struct adapter *adapter = dev->priv;

	int effective_budget = min(*budget, dev->quota);

	int work_done = process_responses(adapter, effective_budget);

	int work_done;



	work_done = process_responses(adapter, min(*budget, dev->quota));

	*budget -= work_done;

	dev->quota -= work_done;



	if (work_done >= effective_budget)

	if (unlikely(responses_pending(adapter)))

		return 1;



	spin_lock_irq(&adapter->async_lock);

	__netif_rx_complete(dev);

	netif_rx_complete(dev);

	writel(adapter->sge->respQ.cidx, adapter->regs + A_SG_SLEEPING);

	writel(adapter->slow_intr_mask | F_PL_INTR_SGE_DATA,

	       adapter->regs + A_PL_ENABLE);

	spin_unlock_irq(&adapter->async_lock);



	return 0;



}



/*
@@ -1635,44 +1643,33 @@ int t1_poll(struct net_device *dev, int *budget) 
irqreturn_t t1_interrupt(int irq, void *data)

{

	struct adapter *adapter = data;

	struct net_device *dev = adapter->sge->netdev;

	struct sge *sge = adapter->sge;

	u32 cause;

	int handled = 0;



	cause = readl(adapter->regs + A_PL_CAUSE);

	if (cause == 0 || cause == ~0)

		return IRQ_NONE;

	int handled;



	spin_lock(&adapter->async_lock);

	if (cause & F_PL_INTR_SGE_DATA) {

		struct respQ *q = &adapter->sge->respQ;

		struct respQ_e *e = &q->entries[q->cidx];

	if (likely(responses_pending(adapter))) {

		struct net_device *dev = sge->netdev;



		handled = 1;

		writel(F_PL_INTR_SGE_DATA, adapter->regs + A_PL_CAUSE);



		if (e->GenerationBit == q->genbit &&

		    __netif_rx_schedule_prep(dev)) {

			if (e->DataValid || process_pure_responses(adapter, e)) {

				/* mask off data IRQ */

				writel(adapter->slow_intr_mask,

				       adapter->regs + A_PL_ENABLE);

				__netif_rx_schedule(sge->netdev);

				goto unlock;

			}

		if (__netif_rx_schedule_prep(dev)) {

			if (process_pure_responses(adapter))

				__netif_rx_schedule(dev);

			else {

				/* no data, no NAPI needed */

			netif_poll_enable(dev);



				writel(sge->respQ.cidx, adapter->regs + A_SG_SLEEPING);

				netif_poll_enable(dev);	/* undo schedule_prep */

			}

		writel(q->cidx, adapter->regs + A_SG_SLEEPING);

	} else

		}

		return IRQ_HANDLED;

	}



	spin_lock(&adapter->async_lock);

	handled = t1_slow_intr_handler(adapter);

	spin_unlock(&adapter->async_lock);



	if (!handled)

		sge->stats.unhandled_irqs++;

unlock:

	spin_unlock(&adapter->async_lock);



	return IRQ_RETVAL(handled != 0);

}
@@ -1695,17 +1692,13 @@ irqreturn_t t1_interrupt(int irq, void *data) 
irqreturn_t t1_interrupt(int irq, void *cookie)

{

	int work_done;

	struct respQ_e *e;

	struct adapter *adapter = cookie;

	struct respQ *Q = &adapter->sge->respQ;



	spin_lock(&adapter->async_lock);

	e = &Q->entries[Q->cidx];

	prefetch(e);



	writel(F_PL_INTR_SGE_DATA, adapter->regs + A_PL_CAUSE);



	if (likely(e->GenerationBit == Q->genbit))

	if (likely(responses_pending(adapter))

		work_done = process_responses(adapter, -1);

	else

		work_done = t1_slow_intr_handler(adapter);