chelsio: NAPI speed improvement
Speedup and cleanup the receive processing by eliminating the
mmio read and a lock round trip.
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/chelsio/sge.c b/drivers/net/chelsio/sge.c
index f94d639..8e287e7 100644
--- a/drivers/net/chelsio/sge.c
+++ b/drivers/net/chelsio/sge.c
@@ -1559,6 +1559,14 @@
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 @@
* 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 @@
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 @@
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;
+ int handled;
- cause = readl(adapter->regs + A_PL_CAUSE);
- if (cause == 0 || cause == ~0)
- return IRQ_NONE;
+ if (likely(responses_pending(adapter))) {
+ struct net_device *dev = sge->netdev;
- 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];
-
- 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 */
+ writel(sge->respQ.cidx, adapter->regs + A_SG_SLEEPING);
+ netif_poll_enable(dev); /* undo schedule_prep */
}
- /* no data, no NAPI needed */
- netif_poll_enable(dev);
-
}
- writel(q->cidx, adapter->regs + A_SG_SLEEPING);
- } else
- handled = t1_slow_intr_handler(adapter);
+ 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 *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);