forcedeth: irq data path optimization

This patch optimizes the irq data paths and cleans up the code.

Signed-Off-By: Ayaz Abdulla <aabdulla@nvidia.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/net/forcedeth.c b/drivers/net/forcedeth.c
index fd91071..7c0f0cc 100644 (file)
--- a/drivers/net/forcedeth.c
+++ b/drivers/net/forcedeth.c
@@ -2777,7 +2777,6 @@ static irqreturn_t nv_nic_irq(int foo, void *data)
                        events = readl(base + NvRegMSIXIrqStatus) & NVREG_IRQSTAT_MASK;
                        writel(NVREG_IRQSTAT_MASK, base + NvRegMSIXIrqStatus);
                }
-               pci_push(base);
                dprintk(KERN_DEBUG "%s: irq: %08x\n", dev->name, events);
                if (!(events & np->irqmask))
                        break;
@@ -2786,22 +2785,46 @@ static irqreturn_t nv_nic_irq(int foo, void *data)
                nv_tx_done(dev);
                spin_unlock(&np->lock);
 
-               if (events & NVREG_IRQ_LINK) {
+#ifdef CONFIG_FORCEDETH_NAPI
+               if (events & NVREG_IRQ_RX_ALL) {
+                       netif_rx_schedule(dev);
+
+                       /* Disable furthur receive irq's */
+                       spin_lock(&np->lock);
+                       np->irqmask &= ~NVREG_IRQ_RX_ALL;
+
+                       if (np->msi_flags & NV_MSI_X_ENABLED)
+                               writel(NVREG_IRQ_RX_ALL, base + NvRegIrqMask);
+                       else
+                               writel(np->irqmask, base + NvRegIrqMask);
+                       spin_unlock(&np->lock);
+               }
+#else
+               if (nv_rx_process(dev, dev->weight)) {
+                       if (unlikely(nv_alloc_rx(dev))) {
+                               spin_lock(&np->lock);
+                               if (!np->in_shutdown)
+                                       mod_timer(&np->oom_kick, jiffies + OOM_REFILL);
+                               spin_unlock(&np->lock);
+                       }
+               }
+#endif
+               if (unlikely(events & NVREG_IRQ_LINK)) {
                        spin_lock(&np->lock);
                        nv_link_irq(dev);
                        spin_unlock(&np->lock);
                }
-               if (np->need_linktimer && time_after(jiffies, np->link_timeout)) {
+               if (unlikely(np->need_linktimer && time_after(jiffies, np->link_timeout))) {
                        spin_lock(&np->lock);
                        nv_linkchange(dev);
                        spin_unlock(&np->lock);
                        np->link_timeout = jiffies + LINK_TIMEOUT;
                }
-               if (events & (NVREG_IRQ_TX_ERR)) {
+               if (unlikely(events & (NVREG_IRQ_TX_ERR))) {
                        dprintk(KERN_DEBUG "%s: received irq with events 0x%x. Probably TX fail.\n",
                                                dev->name, events);
                }
-               if (events & (NVREG_IRQ_UNKNOWN)) {
+               if (unlikely(events & (NVREG_IRQ_UNKNOWN))) {
                        printk(KERN_DEBUG "%s: received irq with unknown events 0x%x. Please report\n",
                                                dev->name, events);
                }
@@ -2822,30 +2845,7 @@ static irqreturn_t nv_nic_irq(int foo, void *data)
                        spin_unlock(&np->lock);
                        break;
                }
-#ifdef CONFIG_FORCEDETH_NAPI
-               if (events & NVREG_IRQ_RX_ALL) {
-                       netif_rx_schedule(dev);
-
-                       /* Disable furthur receive irq's */
-                       spin_lock(&np->lock);
-                       np->irqmask &= ~NVREG_IRQ_RX_ALL;
-
-                       if (np->msi_flags & NV_MSI_X_ENABLED)
-                               writel(NVREG_IRQ_RX_ALL, base + NvRegIrqMask);
-                       else
-                               writel(np->irqmask, base + NvRegIrqMask);
-                       spin_unlock(&np->lock);
-               }
-#else
-               nv_rx_process(dev, dev->weight);
-               if (nv_alloc_rx(dev)) {
-                       spin_lock(&np->lock);
-                       if (!np->in_shutdown)
-                               mod_timer(&np->oom_kick, jiffies + OOM_REFILL);
-                       spin_unlock(&np->lock);
-               }
-#endif
-               if (i > max_interrupt_work) {
+               if (unlikely(i > max_interrupt_work)) {
                        spin_lock(&np->lock);
                        /* disable interrupts on the nic */
                        if (!(np->msi_flags & NV_MSI_X_ENABLED))
@@ -2869,6 +2869,13 @@ static irqreturn_t nv_nic_irq(int foo, void *data)
        return IRQ_RETVAL(i);
 }
 
+#define TX_WORK_PER_LOOP  64
+#define RX_WORK_PER_LOOP  64
+/**
+ * All _optimized functions are used to help increase performance
+ * (reduce CPU and increase throughput). They use descripter version 3,
+ * compiler directives, and reduce memory accesses.
+ */
 static irqreturn_t nv_nic_irq_optimized(int foo, void *data)
 {
        struct net_device *dev = (struct net_device *) data;
@@ -2887,7 +2894,6 @@ static irqreturn_t nv_nic_irq_optimized(int foo, void *data)
                        events = readl(base + NvRegMSIXIrqStatus) & NVREG_IRQSTAT_MASK;
                        writel(NVREG_IRQSTAT_MASK, base + NvRegMSIXIrqStatus);
                }
-               pci_push(base);
                dprintk(KERN_DEBUG "%s: irq: %08x\n", dev->name, events);
                if (!(events & np->irqmask))
                        break;
@@ -2896,22 +2902,46 @@ static irqreturn_t nv_nic_irq_optimized(int foo, void *data)
                nv_tx_done_optimized(dev);
                spin_unlock(&np->lock);
 
-               if (events & NVREG_IRQ_LINK) {
+#ifdef CONFIG_FORCEDETH_NAPI
+               if (events & NVREG_IRQ_RX_ALL) {
+                       netif_rx_schedule(dev);
+
+                       /* Disable furthur receive irq's */
+                       spin_lock(&np->lock);
+                       np->irqmask &= ~NVREG_IRQ_RX_ALL;
+
+                       if (np->msi_flags & NV_MSI_X_ENABLED)
+                               writel(NVREG_IRQ_RX_ALL, base + NvRegIrqMask);
+                       else
+                               writel(np->irqmask, base + NvRegIrqMask);
+                       spin_unlock(&np->lock);
+               }
+#else
+               if (nv_rx_process_optimized(dev, dev->weight)) {
+                       if (unlikely(nv_alloc_rx_optimized(dev))) {
+                               spin_lock(&np->lock);
+                               if (!np->in_shutdown)
+                                       mod_timer(&np->oom_kick, jiffies + OOM_REFILL);
+                               spin_unlock(&np->lock);
+                       }
+               }
+#endif
+               if (unlikely(events & NVREG_IRQ_LINK)) {
                        spin_lock(&np->lock);
                        nv_link_irq(dev);
                        spin_unlock(&np->lock);
                }
-               if (np->need_linktimer && time_after(jiffies, np->link_timeout)) {
+               if (unlikely(np->need_linktimer && time_after(jiffies, np->link_timeout))) {
                        spin_lock(&np->lock);
                        nv_linkchange(dev);
                        spin_unlock(&np->lock);
                        np->link_timeout = jiffies + LINK_TIMEOUT;
                }
-               if (events & (NVREG_IRQ_TX_ERR)) {
+               if (unlikely(events & (NVREG_IRQ_TX_ERR))) {
                        dprintk(KERN_DEBUG "%s: received irq with events 0x%x. Probably TX fail.\n",
                                                dev->name, events);
                }
-               if (events & (NVREG_IRQ_UNKNOWN)) {
+               if (unlikely(events & (NVREG_IRQ_UNKNOWN))) {
                        printk(KERN_DEBUG "%s: received irq with unknown events 0x%x. Please report\n",
                                                dev->name, events);
                }
@@ -2933,30 +2963,7 @@ static irqreturn_t nv_nic_irq_optimized(int foo, void *data)
                        break;
                }
 
-#ifdef CONFIG_FORCEDETH_NAPI
-               if (events & NVREG_IRQ_RX_ALL) {
-                       netif_rx_schedule(dev);
-
-                       /* Disable furthur receive irq's */
-                       spin_lock(&np->lock);
-                       np->irqmask &= ~NVREG_IRQ_RX_ALL;
-
-                       if (np->msi_flags & NV_MSI_X_ENABLED)
-                               writel(NVREG_IRQ_RX_ALL, base + NvRegIrqMask);
-                       else
-                               writel(np->irqmask, base + NvRegIrqMask);
-                       spin_unlock(&np->lock);
-               }
-#else
-               nv_rx_process_optimized(dev, dev->weight);
-               if (nv_alloc_rx_optimized(dev)) {
-                       spin_lock(&np->lock);
-                       if (!np->in_shutdown)
-                               mod_timer(&np->oom_kick, jiffies + OOM_REFILL);
-                       spin_unlock(&np->lock);
-               }
-#endif
-               if (i > max_interrupt_work) {
+               if (unlikely(i > max_interrupt_work)) {
                        spin_lock(&np->lock);
                        /* disable interrupts on the nic */
                        if (!(np->msi_flags & NV_MSI_X_ENABLED))
@@ -2994,7 +3001,6 @@ static irqreturn_t nv_nic_irq_tx(int foo, void *data)
        for (i=0; ; i++) {
                events = readl(base + NvRegMSIXIrqStatus) & NVREG_IRQ_TX_ALL;
                writel(NVREG_IRQ_TX_ALL, base + NvRegMSIXIrqStatus);
-               pci_push(base);
                dprintk(KERN_DEBUG "%s: tx irq: %08x\n", dev->name, events);
                if (!(events & np->irqmask))
                        break;
@@ -3003,11 +3009,11 @@ static irqreturn_t nv_nic_irq_tx(int foo, void *data)
                nv_tx_done_optimized(dev);
                spin_unlock_irqrestore(&np->lock, flags);
 
-               if (events & (NVREG_IRQ_TX_ERR)) {
+               if (unlikely(events & (NVREG_IRQ_TX_ERR))) {
                        dprintk(KERN_DEBUG "%s: received irq with events 0x%x. Probably TX fail.\n",
                                                dev->name, events);
                }
-               if (i > max_interrupt_work) {
+               if (unlikely(i > max_interrupt_work)) {
                        spin_lock_irqsave(&np->lock, flags);
                        /* disable interrupts on the nic */
                        writel(NVREG_IRQ_TX_ALL, base + NvRegIrqMask);
@@ -3105,20 +3111,20 @@ static irqreturn_t nv_nic_irq_rx(int foo, void *data)
        for (i=0; ; i++) {
                events = readl(base + NvRegMSIXIrqStatus) & NVREG_IRQ_RX_ALL;
                writel(NVREG_IRQ_RX_ALL, base + NvRegMSIXIrqStatus);
-               pci_push(base);
                dprintk(KERN_DEBUG "%s: rx irq: %08x\n", dev->name, events);
                if (!(events & np->irqmask))
                        break;
 
-               nv_rx_process_optimized(dev, dev->weight);
-               if (nv_alloc_rx_optimized(dev)) {
-                       spin_lock_irqsave(&np->lock, flags);
-                       if (!np->in_shutdown)
-                               mod_timer(&np->oom_kick, jiffies + OOM_REFILL);
-                       spin_unlock_irqrestore(&np->lock, flags);
+               if (nv_rx_process_optimized(dev, dev->weight)) {
+                       if (unlikely(nv_alloc_rx_optimized(dev))) {
+                               spin_lock_irqsave(&np->lock, flags);
+                               if (!np->in_shutdown)
+                                       mod_timer(&np->oom_kick, jiffies + OOM_REFILL);
+                               spin_unlock_irqrestore(&np->lock, flags);
+                       }
                }
 
-               if (i > max_interrupt_work) {
+               if (unlikely(i > max_interrupt_work)) {
                        spin_lock_irqsave(&np->lock, flags);
                        /* disable interrupts on the nic */
                        writel(NVREG_IRQ_RX_ALL, base + NvRegIrqMask);
@@ -3153,7 +3159,6 @@ static irqreturn_t nv_nic_irq_other(int foo, void *data)
        for (i=0; ; i++) {
                events = readl(base + NvRegMSIXIrqStatus) & NVREG_IRQ_OTHER;
                writel(NVREG_IRQ_OTHER, base + NvRegMSIXIrqStatus);
-               pci_push(base);
                dprintk(KERN_DEBUG "%s: irq: %08x\n", dev->name, events);
                if (!(events & np->irqmask))
                        break;
@@ -3187,7 +3192,7 @@ static irqreturn_t nv_nic_irq_other(int foo, void *data)
                        printk(KERN_DEBUG "%s: received irq with unknown events 0x%x. Please report\n",
                                                dev->name, events);
                }
-               if (i > max_interrupt_work) {
+               if (unlikely(i > max_interrupt_work)) {
                        spin_lock_irqsave(&np->lock, flags);
                        /* disable interrupts on the nic */
                        writel(NVREG_IRQ_OTHER, base + NvRegIrqMask);
@@ -4969,7 +4974,7 @@ static int __devinit nv_probe(struct pci_dev *pci_dev, const struct pci_device_i
 #ifdef CONFIG_NET_POLL_CONTROLLER
        dev->poll_controller = nv_poll_controller;
 #endif
-       dev->weight = 64;
+       dev->weight = RX_WORK_PER_LOOP;
 #ifdef CONFIG_FORCEDETH_NAPI
        dev->poll = nv_napi_poll;
 #endif