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Commit 1f753861 authored by Jesse Brandeburg's avatar Jesse Brandeburg Committed by Jeff Garzik
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[PATCH] e1000: Make the copybreak value a module parameter 



Allow the user to vary the size that copybreak works. Currently cb is enabled
for packets < 256 bytes, but various tests indicate that this should be
configurable for specific use cases. In addition, this parameter allows us
to force never/always during testing to get full and predictable coverage of
both code paths.

Signed-off-by: default avatarJesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: default avatarAuke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 018ea44e

drivers/net/e1000/e1000_main.c

+15 −4
Original line number Diff line number Diff line
@@ -213,6 +213,12 @@ static void e1000_netpoll (struct net_device *netdev); 


extern void e1000_check_options(struct e1000_adapter *adapter);



#define COPYBREAK_DEFAULT 256

static unsigned int copybreak __read_mostly = COPYBREAK_DEFAULT;

module_param(copybreak, uint, 0644);

MODULE_PARM_DESC(copybreak,

	"Maximum size of packet that is copied to a new buffer on receive");



static pci_ers_result_t e1000_io_error_detected(struct pci_dev *pdev,

                     pci_channel_state_t state);

static pci_ers_result_t e1000_io_slot_reset(struct pci_dev *pdev);
@@ -264,7 +270,13 @@ e1000_init_module(void) 
	printk(KERN_INFO "%s\n", e1000_copyright);



	ret = pci_register_driver(&e1000_driver);



	if (copybreak != COPYBREAK_DEFAULT) {

		if (copybreak == 0)

			printk(KERN_INFO "e1000: copybreak disabled\n");

		else

			printk(KERN_INFO "e1000: copybreak enabled for "

			       "packets <= %u bytes\n", copybreak);

	}

	return ret;

}
@@ -4235,8 +4247,7 @@ e1000_clean_rx_irq(struct e1000_adapter *adapter, 
		/* code added for copybreak, this should improve

		 * performance for small packets with large amounts

		 * of reassembly being done in the stack */

#define E1000_CB_LENGTH 256

		if (length < E1000_CB_LENGTH) {

		if (length < copybreak) {

			struct sk_buff *new_skb =

			    netdev_alloc_skb(netdev, length + NET_IP_ALIGN);

			if (new_skb) {
@@ -4394,7 +4405,7 @@ e1000_clean_rx_irq_ps(struct e1000_adapter *adapter, 


		/* page alloc/put takes too long and effects small packet

		 * throughput, so unsplit small packets and save the alloc/put*/

		if (l1 && ((length + l1) <= adapter->rx_ps_bsize0)) {

		if (l1 && (l1 <= copybreak) && ((length + l1) <= adapter->rx_ps_bsize0)) {

			u8 *vaddr;

			/* there is no documentation about how to call

			 * kmap_atomic, so we can't hold the mapping