e1000e: save skb counts in TX to avoid cache misses

In e1000_tx_map, precompute number of segements and bytecounts which
are derived from fields in skb; these are stored in buffer_info.  When
cleaning tx in e1000_clean_tx_irq use the values in the associated
buffer_info for statistics counting, this eliminates cache misses
on skb fields.

Signed-off-by: Tom Herbert <therbert@google.com>
Acked-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/net/e1000e/e1000.h b/drivers/net/e1000e/e1000.h
index 906c4daaabe9..c0b3db40bd73 100644
--- a/drivers/net/e1000e/e1000.h
+++ b/drivers/net/e1000e/e1000.h
@@ -189,6 +189,8 @@ struct e1000_buffer {
                         unsigned long time_stamp;
                         u16 length;
                         u16 next_to_watch;
+                        unsigned int segs;
+                        unsigned int bytecount;
                         u16 mapped_as_page;
                 };
                 /* Rx */