This patch should go through Jeff Garzik and be CCed to
[EMAIL PROTECTED]
John Rigby wrote:
drivers/net/fs_enet/fs_enet-main.c
Add a routine for conditionally copying TX skb's that
are not aligned. Only do this if fep->fpi->align_tx_packets
is set.
In fs_enet_probe set fpi->align_tx_packets to 1 if
the device node has the property fsl,align-tx-packets.
How about setting the property to the size that it needs to be aligned to?
+/*
+ * The 5121 FEC doc says transmit buffers must have 4 byte alignment,
+ * however testing has shown that 2 byte alignment works fine except
+ * for buffers that end in 0x1e.
+ *
+ * Testing with iperf shows about 30% cpu load when copying all packets
+ * vs 19% when only copying 0x1e packets.
+ */
+static struct sk_buff *align_tx_skb(struct net_device *dev, struct sk_buff
*skb)
+{
+ struct sk_buff *skbn;
+ int align = ((unsigned long)skb->data) & (0x1e);
+
+ if (align != 0x1e)
+ return skb;
Are we guaranteed that skb->data is always 2-byte aligned, even with
obscure protocols?
+ if (!skbn) {
+ printk(KERN_WARNING DRV_MODULE_NAME
+ ": %s Memory squeeze, dropping tx packet.\n",
+ dev->name);
Does this need to be rate-limited?
- if (!IS_FEC(match)) {
+ if (IS_FEC(match)) {
+ if (of_get_property(ofdev->node, "fsl,align-tx-packets", NULL))
+ fpi->align_tx_packets = 1;
Might as well check for the property regardless of which ethernet type
it is, in case a similar bug crops up elsewhere.
-Scott
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