ixgbevf: Cleanup variable usage, improve stack performance

This change is meant to help cleanup the usage of temporary variables
within the Rx hot-path by removing unnecessary variables and reducing
the scope of variables that do not need to exist outside the main loop.

CC: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Emil Tantilov 2014-11-08 01:39:30 +00:00 committed by Jeff Kirsher
parent dff8052033
commit b97fe3b1af
1 changed files with 11 additions and 9 deletions

View File

@ -517,26 +517,28 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
struct ixgbevf_ring *rx_ring,
int budget)
{
union ixgbe_adv_rx_desc *rx_desc, *next_rxd;
struct ixgbevf_rx_buffer *rx_buffer_info, *next_buffer;
struct sk_buff *skb;
union ixgbe_adv_rx_desc *rx_desc;
unsigned int i;
unsigned int total_rx_bytes = 0, total_rx_packets = 0;
u16 cleaned_count = ixgbevf_desc_unused(rx_ring);
i = rx_ring->next_to_clean;
rx_desc = IXGBEVF_RX_DESC(rx_ring, i);
rx_buffer_info = &rx_ring->rx_buffer_info[i];
while (ixgbevf_test_staterr(rx_desc, IXGBE_RXD_STAT_DD)) {
union ixgbe_adv_rx_desc *next_rxd;
struct ixgbevf_rx_buffer *rx_buffer_info;
struct sk_buff *skb;
if (!budget)
break;
budget--;
rmb(); /* read descriptor and rx_buffer_info after status DD */
rx_buffer_info = &rx_ring->rx_buffer_info[i];
skb = rx_buffer_info->skb;
prefetch(skb->data - NET_IP_ALIGN);
prefetch(skb->data);
rx_buffer_info->skb = NULL;
dma_unmap_single(rx_ring->dev, rx_buffer_info->dma,
@ -545,18 +547,17 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
rx_buffer_info->dma = 0;
skb_put(skb, le16_to_cpu(rx_desc->wb.upper.length));
cleaned_count++;
i++;
if (i == rx_ring->count)
i = 0;
next_rxd = IXGBEVF_RX_DESC(rx_ring, i);
prefetch(next_rxd);
cleaned_count++;
next_buffer = &rx_ring->rx_buffer_info[i];
if (!(ixgbevf_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP))) {
skb->next = next_buffer->skb;
skb->next = rx_ring->rx_buffer_info[i].skb;
IXGBE_CB(skb->next)->prev = skb;
rx_ring->rx_stats.non_eop_descs++;
goto next_desc;
@ -609,6 +610,7 @@ next_desc:
/* use prefetched values */
rx_desc = next_rxd;
rx_buffer_info = &rx_ring->rx_buffer_info[i];
rx_desc = IXGBEVF_RX_DESC(rx_ring, i);
}
rx_ring->next_to_clean = i;