e1000: Added a performance enhancement - prefetch
- this implementation of prefetch was tested on new and old hardware
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: John Ronciak <john.ronciak@intel.com>
diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index d641fbc..b572a12 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -3569,10 +3569,15 @@
skb = buffer_info->skb;
buffer_info->skb = NULL;
+ prefetch(skb->data - NET_IP_ALIGN);
+
if (++i == rx_ring->count) i = 0;
next_rxd = E1000_RX_DESC(*rx_ring, i);
+ prefetch(next_rxd);
+
next_buffer = &rx_ring->buffer_info[i];
next_skb = next_buffer->skb;
+ prefetch(next_skb->data - NET_IP_ALIGN);
cleaned = TRUE;
cleaned_count++;
@@ -3668,6 +3673,7 @@
cleaned_count = 0;
}
+ /* use prefetched values */
rx_desc = next_rxd;
buffer_info = next_buffer;
}
@@ -3710,9 +3716,9 @@
i = rx_ring->next_to_clean;
rx_desc = E1000_RX_DESC_PS(*rx_ring, i);
staterr = le32_to_cpu(rx_desc->wb.middle.status_error);
- buffer_info = &rx_ring->buffer_info[i];
while (staterr & E1000_RXD_STAT_DD) {
+ buffer_info = &rx_ring->buffer_info[i];
ps_page = &rx_ring->ps_page[i];
ps_page_dma = &rx_ring->ps_page_dma[i];
#ifdef CONFIG_E1000_NAPI
@@ -3722,10 +3728,16 @@
#endif
skb = buffer_info->skb;
+ /* in the packet split case this is header only */
+ prefetch(skb->data - NET_IP_ALIGN);
+
if (++i == rx_ring->count) i = 0;
next_rxd = E1000_RX_DESC_PS(*rx_ring, i);
+ prefetch(next_rxd);
+
next_buffer = &rx_ring->buffer_info[i];
next_skb = next_buffer->skb;
+ prefetch(next_skb->data - NET_IP_ALIGN);
cleaned = TRUE;
cleaned_count++;
@@ -3787,9 +3799,8 @@
}
for (j = 0; j < adapter->rx_ps_pages; j++) {
- if (!(length = le16_to_cpu(rx_desc->wb.upper.length[j])))
+ if (!(length= le16_to_cpu(rx_desc->wb.upper.length[j])))
break;
-
pci_unmap_page(pdev, ps_page_dma->ps_page_dma[j],
PAGE_SIZE, PCI_DMA_FROMDEVICE);
ps_page_dma->ps_page_dma[j] = 0;
@@ -3837,6 +3848,7 @@
cleaned_count = 0;
}
+ /* use prefetched values */
rx_desc = next_rxd;
buffer_info = next_buffer;