ixgb: add performance enhancements to the buffer_info struct
o modify the rx refill logic and tail bump
o add counter for failures
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: John Ronciak <john.ronciak@intel.com>
diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index 0905a82..27034b3 100644
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -929,17 +929,20 @@
struct ixgb_buffer *buffer_info)
{
struct pci_dev *pdev = adapter->pdev;
- if(buffer_info->dma) {
- pci_unmap_page(pdev,
- buffer_info->dma,
- buffer_info->length,
- PCI_DMA_TODEVICE);
- buffer_info->dma = 0;
- }
- if(buffer_info->skb) {
+
+ if (buffer_info->dma)
+ pci_unmap_page(pdev, buffer_info->dma, buffer_info->length,
+ PCI_DMA_TODEVICE);
+
+ if (buffer_info->skb)
dev_kfree_skb_any(buffer_info->skb);
- buffer_info->skb = NULL;
- }
+
+ buffer_info->skb = NULL;
+ buffer_info->dma = 0;
+ buffer_info->time_stamp = 0;
+ /* these fields must always be initialized in tx
+ * buffer_info->length = 0;
+ * buffer_info->next_to_watch = 0; */
}
/**
@@ -1314,6 +1317,7 @@
size,
PCI_DMA_TODEVICE);
buffer_info->time_stamp = jiffies;
+ buffer_info->next_to_watch = 0;
len -= size;
offset += size;
@@ -1345,6 +1349,7 @@
size,
PCI_DMA_TODEVICE);
buffer_info->time_stamp = jiffies;
+ buffer_info->next_to_watch = 0;
len -= size;
offset += size;
@@ -1940,6 +1945,7 @@
#endif
status = rx_desc->status;
skb = buffer_info->skb;
+ buffer_info->skb = NULL;
prefetch(skb->data);
@@ -2013,7 +2019,6 @@
rxdesc_done:
/* clean up descriptor, might be written over by hw */
rx_desc->status = 0;
- buffer_info->skb = NULL;
/* use prefetched values */
rx_desc = next_rxd;
@@ -2053,12 +2058,18 @@
/* leave three descriptors unused */
while(--cleancount > 2) {
- rx_desc = IXGB_RX_DESC(*rx_ring, i);
+ /* recycle! its good for you */
+ if (!(skb = buffer_info->skb))
+ skb = dev_alloc_skb(adapter->rx_buffer_len
+ + NET_IP_ALIGN);
+ else {
+ skb_trim(skb, 0);
+ goto map_skb;
+ }
- skb = dev_alloc_skb(adapter->rx_buffer_len + NET_IP_ALIGN);
-
- if(unlikely(!skb)) {
+ if (unlikely(!skb)) {
/* Better luck next round */
+ adapter->alloc_rx_buff_failed++;
break;
}
@@ -2072,33 +2083,36 @@
buffer_info->skb = skb;
buffer_info->length = adapter->rx_buffer_len;
- buffer_info->dma =
- pci_map_single(pdev,
- skb->data,
- adapter->rx_buffer_len,
- PCI_DMA_FROMDEVICE);
+map_skb:
+ buffer_info->dma = pci_map_single(pdev,
+ skb->data,
+ adapter->rx_buffer_len,
+ PCI_DMA_FROMDEVICE);
+ rx_desc = IXGB_RX_DESC(*rx_ring, i);
rx_desc->buff_addr = cpu_to_le64(buffer_info->dma);
/* guarantee DD bit not set now before h/w gets descriptor
* this is the rest of the workaround for h/w double
* writeback. */
rx_desc->status = 0;
- if((i & ~(num_group_tail_writes- 1)) == i) {
- /* Force memory writes to complete before letting h/w
- * know there are new descriptors to fetch. (Only
- * applicable for weak-ordered memory model archs,
- * such as IA-64). */
- wmb();
-
- IXGB_WRITE_REG(&adapter->hw, RDT, i);
- }
if(++i == rx_ring->count) i = 0;
buffer_info = &rx_ring->buffer_info[i];
}
- rx_ring->next_to_use = i;
+ if (likely(rx_ring->next_to_use != i)) {
+ rx_ring->next_to_use = i;
+ if (unlikely(i-- == 0))
+ i = (rx_ring->count - 1);
+
+ /* Force memory writes to complete before letting h/w
+ * know there are new descriptors to fetch. (Only
+ * applicable for weak-ordered memory model archs, such
+ * as IA-64). */
+ wmb();
+ IXGB_WRITE_REG(&adapter->hw, RDT, i);
+ }
}
/**