RNDIS: Add Data aggregation (multi packet) support
Add data aggregation support using RNDIS Multi Packet feature
to achieve better UDP Downlink throughput. Max 3 RNDIS Packets
aggregated into one RNDIS Packet with this implementation.
With this change, seeing UDP Downlink throughput increase
from 90 Mbps to above 100 Mbps when using Iperf and sending
data more than 100 Mbps.
Change-Id: I21c39482718944bb1b1068bdd02f626531e58f08
Signed-off-by: Mayank Rana <mrana@codeaurora.org>
Signed-off-by: Rajkumar Raghupathy <raghup@codeaurora.org>
diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c
index 57b0e13..12e3425 100644
--- a/drivers/usb/gadget/function/u_ether.c
+++ b/drivers/usb/gadget/function/u_ether.c
@@ -67,6 +67,11 @@
spinlock_t req_lock; /* guard {rx,tx}_reqs */
struct list_head tx_reqs, rx_reqs;
unsigned tx_qlen;
+/* Minimum number of TX USB request queued to UDC */
+#define TX_REQ_THRESHOLD 5
+ int no_tx_req_used;
+ int tx_skb_hold_count;
+ u32 tx_req_bufsize;
struct sk_buff_head rx_frames;
@@ -467,6 +472,11 @@
{
struct sk_buff *skb = req->context;
struct eth_dev *dev = ep->driver_data;
+ struct net_device *net = dev->net;
+ struct usb_request *new_req;
+ struct usb_ep *in;
+ int length;
+ int retval;
switch (req->status) {
default:
@@ -477,14 +487,73 @@
case -ESHUTDOWN: /* disconnect etc */
break;
case 0:
- dev->net->stats.tx_bytes += skb->len;
+ if (!req->zero)
+ dev->net->stats.tx_bytes += req->length-1;
+ else
+ dev->net->stats.tx_bytes += req->length;
}
dev->net->stats.tx_packets++;
spin_lock(&dev->req_lock);
- list_add(&req->list, &dev->tx_reqs);
- spin_unlock(&dev->req_lock);
- dev_kfree_skb_any(skb);
+ list_add_tail(&req->list, &dev->tx_reqs);
+
+ if (dev->port_usb->multi_pkt_xfer) {
+ dev->no_tx_req_used--;
+ req->length = 0;
+ in = dev->port_usb->in_ep;
+
+ if (!list_empty(&dev->tx_reqs)) {
+ new_req = container_of(dev->tx_reqs.next,
+ struct usb_request, list);
+ list_del(&new_req->list);
+ spin_unlock(&dev->req_lock);
+ if (new_req->length > 0) {
+ length = new_req->length;
+
+ /* NCM requires no zlp if transfer is
+ * dwNtbInMaxSize */
+ if (dev->port_usb->is_fixed &&
+ length == dev->port_usb->fixed_in_len &&
+ (length % in->maxpacket) == 0)
+ new_req->zero = 0;
+ else
+ new_req->zero = 1;
+
+ /* use zlp framing on tx for strict CDC-Ether
+ * conformance, though any robust network rx
+ * path ignores extra padding. and some hardware
+ * doesn't like to write zlps.
+ */
+ if (new_req->zero && !dev->zlp &&
+ (length % in->maxpacket) == 0) {
+ new_req->zero = 0;
+ length++;
+ }
+
+ new_req->length = length;
+ retval = usb_ep_queue(in, new_req, GFP_ATOMIC);
+ switch (retval) {
+ default:
+ DBG(dev, "tx queue err %d\n", retval);
+ break;
+ case 0:
+ spin_lock(&dev->req_lock);
+ dev->no_tx_req_used++;
+ spin_unlock(&dev->req_lock);
+ net->trans_start = jiffies;
+ }
+ } else {
+ spin_lock(&dev->req_lock);
+ list_add(&new_req->list, &dev->tx_reqs);
+ spin_unlock(&dev->req_lock);
+ }
+ } else {
+ spin_unlock(&dev->req_lock);
+ }
+ } else {
+ spin_unlock(&dev->req_lock);
+ dev_kfree_skb_any(skb);
+ }
if (netif_carrier_ok(dev->net))
netif_wake_queue(dev->net);
@@ -495,6 +564,26 @@
return cdc_filter & USB_CDC_PACKET_TYPE_PROMISCUOUS;
}
+static void alloc_tx_buffer(struct eth_dev *dev)
+{
+ struct list_head *act;
+ struct usb_request *req;
+
+ dev->tx_req_bufsize = (TX_SKB_HOLD_THRESHOLD *
+ (dev->net->mtu
+ + sizeof(struct ethhdr)
+ /* size of rndis_packet_msg_type */
+ + 44
+ + 22));
+
+ list_for_each(act, &dev->tx_reqs) {
+ req = container_of(act, struct usb_request, list);
+ if (!req->buf)
+ req->buf = kmalloc(dev->tx_req_bufsize,
+ GFP_ATOMIC);
+ }
+}
+
static netdev_tx_t eth_start_xmit(struct sk_buff *skb,
struct net_device *net)
{
@@ -521,6 +610,10 @@
return NETDEV_TX_OK;
}
+ /* Allocate memory for tx_reqs to support multi packet transfer */
+ if (dev->port_usb->multi_pkt_xfer && !dev->tx_req_bufsize)
+ alloc_tx_buffer(dev);
+
/* apply outgoing CDC or RNDIS filters */
if (skb && !is_promisc(cdc_filter)) {
u8 *dest = skb->data;
@@ -584,9 +677,37 @@
}
}
- length = skb->len;
- req->buf = skb->data;
- req->context = skb;
+ spin_lock_irqsave(&dev->req_lock, flags);
+ dev->tx_skb_hold_count++;
+ spin_unlock_irqrestore(&dev->req_lock, flags);
+
+ if (dev->port_usb->multi_pkt_xfer) {
+ memcpy(req->buf + req->length, skb->data, skb->len);
+ req->length = req->length + skb->len;
+ length = req->length;
+ dev_kfree_skb_any(skb);
+
+ spin_lock_irqsave(&dev->req_lock, flags);
+ if (dev->tx_skb_hold_count < TX_SKB_HOLD_THRESHOLD) {
+ if (dev->no_tx_req_used > TX_REQ_THRESHOLD) {
+ list_add(&req->list, &dev->tx_reqs);
+ spin_unlock_irqrestore(&dev->req_lock, flags);
+ goto success;
+ }
+ }
+
+ dev->no_tx_req_used++;
+ spin_unlock_irqrestore(&dev->req_lock, flags);
+
+ spin_lock_irqsave(&dev->lock, flags);
+ dev->tx_skb_hold_count = 0;
+ spin_unlock_irqrestore(&dev->lock, flags);
+ } else {
+ length = skb->len;
+ req->buf = skb->data;
+ req->context = skb;
+ }
+
req->complete = tx_complete;
/* NCM requires no zlp if transfer is dwNtbInMaxSize */
@@ -602,8 +723,10 @@
* though any robust network rx path ignores extra padding.
* and some hardware doesn't like to write zlps.
*/
- if (req->zero && !dev->zlp && (length % in->maxpacket) == 0)
+ if (req->zero && !dev->zlp && (length % in->maxpacket) == 0) {
+ req->zero = 0;
length++;
+ }
req->length = length;
@@ -611,7 +734,7 @@
if (gadget_is_dualspeed(dev->gadget) &&
(dev->gadget->speed == USB_SPEED_HIGH)) {
dev->tx_qlen++;
- if (dev->tx_qlen == qmult) {
+ if (dev->tx_qlen == (qmult/2)) {
req->no_interrupt = 0;
dev->tx_qlen = 0;
} else {
@@ -631,7 +754,8 @@
}
if (retval) {
- dev_kfree_skb_any(skb);
+ if (!dev->port_usb->multi_pkt_xfer)
+ dev_kfree_skb_any(skb);
drop:
dev->net->stats.tx_dropped++;
multiframe:
@@ -641,6 +765,7 @@
list_add(&req->list, &dev->tx_reqs);
spin_unlock_irqrestore(&dev->req_lock, flags);
}
+success:
return NETDEV_TX_OK;
}
@@ -1101,6 +1226,9 @@
dev->ul_max_pkts_per_xfer = link->ul_max_pkts_per_xfer;
spin_lock(&dev->lock);
+ dev->tx_skb_hold_count = 0;
+ dev->no_tx_req_used = 0;
+ dev->tx_req_bufsize = 0;
dev->port_usb = link;
if (netif_running(dev->net)) {
if (link->open)
@@ -1168,6 +1296,8 @@
list_del(&req->list);
spin_unlock(&dev->req_lock);
+ if (link->multi_pkt_xfer)
+ kfree(req->buf);
usb_ep_free_request(link->in_ep, req);
spin_lock(&dev->req_lock);
}