via-velocity: Implement NAPI support

This patch adds NAPI support for VIA velocity. The new velocity_poll
function also pairs tx/rx handling twice which improves perforamance on
some workloads (e.g., netperf UDP_STREAM) significantly (that part is
from the VIA driver).

Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/via-velocity.c b/drivers/net/via-velocity.c
index 7c362b24270447a84542a5ff1f12b922b1f33178..47b28821589b4ffac0635be3c42fb4a80fa762e8 100644 (file)
--- a/drivers/net/via-velocity.c
+++ b/drivers/net/via-velocity.c
@@ -354,12 +354,6 @@ VELOCITY_PARAM(ValPktLen, "Receiving or Drop invalid 802.3 frame");
 */
 VELOCITY_PARAM(wol_opts, "Wake On Lan options");
 
-#define INT_WORKS_DEF   20
-#define INT_WORKS_MIN   10
-#define INT_WORKS_MAX   64
-
-VELOCITY_PARAM(int_works, "Number of packets per interrupt services");
-
 static int rx_copybreak = 200;
 module_param(rx_copybreak, int, 0644);
 MODULE_PARM_DESC(rx_copybreak, "Copy breakpoint for copy-only-tiny-frames");
@@ -503,7 +497,6 @@ static void __devinit velocity_get_options(struct velocity_opt *opts, int index,
        velocity_set_bool_opt(&opts->flags, ValPktLen[index], VAL_PKT_LEN_DEF, VELOCITY_FLAGS_VAL_PKT_LEN, "ValPktLen", devname);
        velocity_set_int_opt((int *) &opts->spd_dpx, speed_duplex[index], MED_LNK_MIN, MED_LNK_MAX, MED_LNK_DEF, "Media link mode", devname);
        velocity_set_int_opt((int *) &opts->wol_opts, wol_opts[index], WOL_OPT_MIN, WOL_OPT_MAX, WOL_OPT_DEF, "Wake On Lan options", devname);
-       velocity_set_int_opt((int *) &opts->int_works, int_works[index], INT_WORKS_MIN, INT_WORKS_MAX, INT_WORKS_DEF, "Interrupt service works", devname);
        opts->numrx = (opts->numrx & ~3);
 }
 
@@ -2109,13 +2102,14 @@ static int velocity_receive_frame(struct velocity_info *vptr, int idx)
  *     any received packets from the receive queue. Hand the ring
  *     slots back to the adapter for reuse.
  */
-static int velocity_rx_srv(struct velocity_info *vptr, int status)
+static int velocity_rx_srv(struct velocity_info *vptr, int status,
+               int budget_left)
 {
        struct net_device_stats *stats = &vptr->dev->stats;
        int rd_curr = vptr->rx.curr;
        int works = 0;
 
-       do {
+       while (works < budget_left) {
                struct rx_desc *rd = vptr->rx.ring + rd_curr;
 
                if (!vptr->rx.info[rd_curr].skb)
@@ -2146,7 +2140,8 @@ static int velocity_rx_srv(struct velocity_info *vptr, int status)
                rd_curr++;
                if (rd_curr >= vptr->options.numrx)
                        rd_curr = 0;
-       } while (++works <= 15);
+               works++;
+       }
 
        vptr->rx.curr = rd_curr;
 
@@ -2157,6 +2152,40 @@ static int velocity_rx_srv(struct velocity_info *vptr, int status)
        return works;
 }
 
+static int velocity_poll(struct napi_struct *napi, int budget)
+{
+       struct velocity_info *vptr = container_of(napi,
+                       struct velocity_info, napi);
+       unsigned int rx_done;
+       u32 isr_status;
+
+       spin_lock(&vptr->lock);
+       isr_status = mac_read_isr(vptr->mac_regs);
+
+       /* Ack the interrupt */
+       mac_write_isr(vptr->mac_regs, isr_status);
+       if (isr_status & (~(ISR_PRXI | ISR_PPRXI | ISR_PTXI | ISR_PPTXI)))
+               velocity_error(vptr, isr_status);
+
+       /*
+        * Do rx and tx twice for performance (taken from the VIA
+        * out-of-tree driver).
+        */
+       rx_done = velocity_rx_srv(vptr, isr_status, budget / 2);
+       velocity_tx_srv(vptr, isr_status);
+       rx_done += velocity_rx_srv(vptr, isr_status, budget - rx_done);
+       velocity_tx_srv(vptr, isr_status);
+
+       spin_unlock(&vptr->lock);
+
+       /* If budget not fully consumed, exit the polling mode */
+       if (rx_done < budget) {
+               napi_complete(napi);
+               mac_enable_int(vptr->mac_regs);
+       }
+
+       return rx_done;
+}
 
 /**
  *     velocity_intr           -       interrupt callback
@@ -2173,8 +2202,6 @@ static irqreturn_t velocity_intr(int irq, void *dev_instance)
        struct net_device *dev = dev_instance;
        struct velocity_info *vptr = netdev_priv(dev);
        u32 isr_status;
-       int max_count = 0;
-
 
        spin_lock(&vptr->lock);
        isr_status = mac_read_isr(vptr->mac_regs);
@@ -2185,32 +2212,13 @@ static irqreturn_t velocity_intr(int irq, void *dev_instance)
                return IRQ_NONE;
        }
 
-       mac_disable_int(vptr->mac_regs);
-
-       /*
-        *      Keep processing the ISR until we have completed
-        *      processing and the isr_status becomes zero
-        */
-
-       while (isr_status != 0) {
-               mac_write_isr(vptr->mac_regs, isr_status);
-               if (isr_status & (~(ISR_PRXI | ISR_PPRXI | ISR_PTXI | ISR_PPTXI)))
-                       velocity_error(vptr, isr_status);
-               if (isr_status & (ISR_PRXI | ISR_PPRXI))
-                       max_count += velocity_rx_srv(vptr, isr_status);
-               if (isr_status & (ISR_PTXI | ISR_PPTXI))
-                       max_count += velocity_tx_srv(vptr, isr_status);
-               isr_status = mac_read_isr(vptr->mac_regs);
-               if (max_count > vptr->options.int_works) {
-                       printk(KERN_WARNING "%s: excessive work at interrupt.\n",
-                               dev->name);
-                       max_count = 0;
-               }
+       if (likely(napi_schedule_prep(&vptr->napi))) {
+               mac_disable_int(vptr->mac_regs);
+               __napi_schedule(&vptr->napi);
        }
        spin_unlock(&vptr->lock);
-       mac_enable_int(vptr->mac_regs);
-       return IRQ_HANDLED;
 
+       return IRQ_HANDLED;
 }
 
 /**
@@ -2250,6 +2258,7 @@ static int velocity_open(struct net_device *dev)
 
        mac_enable_int(vptr->mac_regs);
        netif_start_queue(dev);
+       napi_enable(&vptr->napi);
        vptr->flags |= VELOCITY_FLAGS_OPENED;
 out:
        return ret;
@@ -2485,6 +2494,7 @@ static int velocity_close(struct net_device *dev)
 {
        struct velocity_info *vptr = netdev_priv(dev);
 
+       napi_disable(&vptr->napi);
        netif_stop_queue(dev);
        velocity_shutdown(vptr);
 
@@ -2803,6 +2813,7 @@ static int __devinit velocity_found1(struct pci_dev *pdev, const struct pci_devi
        dev->irq = pdev->irq;
        dev->netdev_ops = &velocity_netdev_ops;
        dev->ethtool_ops = &velocity_ethtool_ops;
+       netif_napi_add(dev, &vptr->napi, velocity_poll, VELOCITY_NAPI_WEIGHT);
 
        dev->features |= NETIF_F_HW_VLAN_TX | NETIF_F_HW_VLAN_FILTER |
                NETIF_F_HW_VLAN_RX;

diff --git a/drivers/net/via-velocity.h b/drivers/net/via-velocity.h
index 499da64773ee14bf2a4ffea9b9aac5598a5d3981..d37a30329312c4aaab31a33708a5f2b9688f8c5a 100644 (file)
--- a/drivers/net/via-velocity.h
+++ b/drivers/net/via-velocity.h
@@ -32,6 +32,7 @@
 #define VELOCITY_VERSION       "1.14"
 
 #define VELOCITY_IO_SIZE       256
+#define VELOCITY_NAPI_WEIGHT   64
 
 #define PKT_BUF_SZ          1540
 
@@ -1562,6 +1563,8 @@ struct velocity_info {
        u32 ticks;
 
        u8 rev_id;
+
+       struct napi_struct napi;
 };
 
 /**