From: "Weinn Jheng" <clanlab.proj@xxxxxxxxx>
In order to reduce the interrupt times in the embedded system,
a receiving workqueue is introduced.
This modification also enhanced the overall throughput as the
benefits of reducing interrupt occurrence.
This work was derived from previous work:
u_ether: move hardware transmit to RX workqueue.
Which should be base on codeaurora's work.
However, the benchmark on my platform shows the throughput
with workqueue is slightly better than NAPI.
Signed-off-by: Weinn Jheng <clanlab.proj@xxxxxxxxx>
Cc: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Stephen Hemminger <shemminger@xxxxxxxxxx>
Cc: Felipe Balbi <balbi@xxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Manu Gautam <mgautam@xxxxxxxxxxxxxx>
---
drivers/usb/gadget/u_ether.c | 101 ++++++++++++++++++++++++++++---------------
1 file changed, 66 insertions(+), 35 deletions(-)
diff --git a/drivers/usb/gadget/u_ether.c b/drivers/usb/gadget/u_ether.c
index b7d4f82..50d09c2 100644
--- a/drivers/usb/gadget/u_ether.c
+++ b/drivers/usb/gadget/u_ether.c
@@ -48,6 +48,8 @@
#define UETH__VERSION "29-May-2008"
+#define GETHER_NAPI_WEIGHT 32
+
struct eth_dev {
/* lock is held while accessing port_usb
*/
@@ -72,6 +74,7 @@ struct eth_dev {
struct sk_buff_head *list);
struct work_struct work;
+ struct napi_struct rx_napi;
unsigned long todo;
#define WORK_RX_MEMORY 0
@@ -253,18 +256,16 @@ enomem:
DBG(dev, "rx submit --> %d\n", retval);
if (skb)
dev_kfree_skb_any(skb);
- spin_lock_irqsave(&dev->req_lock, flags);
- list_add(&req->list, &dev->rx_reqs);
- spin_unlock_irqrestore(&dev->req_lock, flags);
}
return retval;
}
static void rx_complete(struct usb_ep *ep, struct usb_request *req)
{
- struct sk_buff *skb = req->context, *skb2;
+ struct sk_buff *skb = req->context;
struct eth_dev *dev = ep->driver_data;
int status = req->status;
+ bool rx_queue = 0;
switch (status) {
@@ -288,30 +289,8 @@ static void rx_complete(struct usb_ep *ep, struct usb_request *req)
} else {
skb_queue_tail(&dev->rx_frames, skb);
}
- skb = NULL;
-
- skb2 = skb_dequeue(&dev->rx_frames);
- while (skb2) {
- if (status < 0
- || ETH_HLEN > skb2->len
- || skb2->len > VLAN_ETH_FRAME_LEN) {
- dev->net->stats.rx_errors++;
- dev->net->stats.rx_length_errors++;
- DBG(dev, "rx length %d\n", skb2->len);
- dev_kfree_skb_any(skb2);
- goto next_frame;
- }
- skb2->protocol = eth_type_trans(skb2, dev->net);
- dev->net->stats.rx_packets++;
- dev->net->stats.rx_bytes += skb2->len;
-
- /* no buffer copies needed, unless hardware can't
- * use skb buffers.
- */
- status = netif_rx(skb2);
-next_frame:
- skb2 = skb_dequeue(&dev->rx_frames);
- }
+ if (!status)
+ rx_queue = 1;
break;
/* software-driven interface shutdown */
@@ -334,22 +313,20 @@ quiesce:
/* FALLTHROUGH */
default:
+ rx_queue = 1;
+ dev_kfree_skb_any(skb);
dev->net->stats.rx_errors++;
DBG(dev, "rx status %d\n", status);
break;
}
- if (skb)
- dev_kfree_skb_any(skb);
- if (!netif_running(dev->net)) {
clean:
spin_lock(&dev->req_lock);
list_add(&req->list, &dev->rx_reqs);
spin_unlock(&dev->req_lock);
- req = NULL;
- }
- if (req)
- rx_submit(dev, req, GFP_ATOMIC);
+
+ if (rx_queue && likely(napi_schedule_prep(&dev->rx_napi)))
+ __napi_schedule(&dev->rx_napi);
}
static int prealloc(struct list_head *list, struct usb_ep *ep, unsigned n)
@@ -414,16 +391,24 @@ static void rx_fill(struct eth_dev *dev, gfp_t gfp_flags)
{
struct usb_request *req;
unsigned long flags;
+ int rx_counts = 0;
/* fill unused rxq slots with some skb */
spin_lock_irqsave(&dev->req_lock, flags);
while (!list_empty(&dev->rx_reqs)) {
+
+ if (++rx_counts > qlen(dev->gadget, dev->qmult))
+ break;
+
req = container_of(dev->rx_reqs.next,
struct usb_request, list);
list_del_init(&req->list);
spin_unlock_irqrestore(&dev->req_lock, flags);
if (rx_submit(dev, req, gfp_flags) < 0) {
+ spin_lock_irqsave(&dev->req_lock, flags);
+ list_add(&req->list, &dev->rx_reqs);
+ spin_unlock_irqrestore(&dev->req_lock, flags);
defer_kevent(dev, WORK_RX_MEMORY);
return;
}
@@ -433,6 +418,41 @@ static void rx_fill(struct eth_dev *dev, gfp_t gfp_flags)
spin_unlock_irqrestore(&dev->req_lock, flags);
}
+static int gether_poll(struct napi_struct *napi, int budget)
+{
+ struct eth_dev *dev = container_of(napi, struct eth_dev, rx_napi);
+ struct sk_buff *skb;
+ unsigned int work_done = 0;
+ int status = 0;
+
+ while ((skb = skb_dequeue(&dev->rx_frames))) {
+ if (status < 0
+ || ETH_HLEN > skb->len
+ || skb->len > VLAN_ETH_FRAME_LEN) {
+ dev->net->stats.rx_errors++;
+ dev->net->stats.rx_length_errors++;
+ DBG(dev, "rx length %d\n", skb->len);
+ dev_kfree_skb_any(skb);
+ continue;
+ }
+ skb->protocol = eth_type_trans(skb, dev->net);
+ dev->net->stats.rx_packets++;
+ dev->net->stats.rx_bytes += skb->len;
+
+ status = netif_rx_ni(skb);
+ }
+
+ if (netif_running(dev->net)) {
+ rx_fill(dev, GFP_KERNEL);
+ work_done++;
+ }
+
+ if (work_done < budget)
+ napi_complete(&dev->rx_napi);
+
+ return work_done;
+}
+
static void eth_work(struct work_struct *work)
{
struct eth_dev *dev = container_of(work, struct eth_dev, work);
@@ -625,6 +645,7 @@ static void eth_start(struct eth_dev *dev, gfp_t gfp_flags)
/* and open the tx floodgates */
atomic_set(&dev->tx_qlen, 0);
netif_wake_queue(dev->net);
+ napi_enable(&dev->rx_napi);
}
static int eth_open(struct net_device *net)
@@ -651,6 +672,7 @@ static int eth_stop(struct net_device *net)
unsigned long flags;
VDBG(dev, "%s\n", __func__);
+ napi_disable(&dev->rx_napi);
netif_stop_queue(net);
DBG(dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld\n",
@@ -768,6 +790,7 @@ struct eth_dev *gether_setup_name(struct usb_gadget *g,
return ERR_PTR(-ENOMEM);
dev = netdev_priv(net);
+ netif_napi_add(net, &dev->rx_napi, gether_poll, GETHER_NAPI_WEIGHT);
spin_lock_init(&dev->lock);
spin_lock_init(&dev->req_lock);
INIT_WORK(&dev->work, eth_work);
@@ -830,6 +853,7 @@ struct net_device *gether_setup_name_default(const char *netname)
return ERR_PTR(-ENOMEM);
dev = netdev_priv(net);
+ netif_napi_add(net, &dev->rx_napi, gether_poll, GETHER_NAPI_WEIGHT);
spin_lock_init(&dev->lock);
spin_lock_init(&dev->req_lock);
INIT_WORK(&dev->work, eth_work);
@@ -1113,6 +1137,7 @@ void gether_disconnect(struct gether *link)
{
struct eth_dev *dev = link->ioport;
struct usb_request *req;
+ struct sk_buff *skb;
WARN_ON(!dev);
if (!dev)
@@ -1139,6 +1164,12 @@ void gether_disconnect(struct gether *link)
spin_lock(&dev->req_lock);
}
spin_unlock(&dev->req_lock);
+
+ spin_lock(&dev->rx_frames.lock);
+ while ((skb = __skb_dequeue(&dev->rx_frames)))
+ dev_kfree_skb_any(skb);
+ spin_unlock(&dev->rx_frames.lock);
+
link->in_ep->driver_data = NULL;
link->in_ep->desc = NULL;
--
1.9.rc1
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
