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authorAlexander Duyck2012-05-24 03:59:27 +0200
committerJeff Kirsher2012-07-22 01:04:51 +0200
commit252562c207a850106d9d5b41a41d29f96c0530b7 (patch)
tree7584cd94d2069a9466c6640b70189a7254d58b0e /drivers/net/ethernet/intel/ixgbe/ixgbe.h
parentixgbevf: Fix namespace issue with ixgbe_write_eitr (diff)
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ixgbe: Reduce Rx header size to what is actually used
The recent changes to netdev_alloc_skb actually make it so that the size of the buffer now actually has a more direct input on the truesize. So in order to make best use of the piece of a page we are allocated I am reducing the IXGBE_RX_HDR_SIZE to 256 so that our truesize will be reduced by 256 bytes as well. This should result in performance improvements since the number of uses per page should increase from 4 to 6 in the case of a 4K page. In addition we should see socket performance improvements due to the truesize dropping to less than 1K for buffers less than 256 bytes. Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Diffstat (limited to 'drivers/net/ethernet/intel/ixgbe/ixgbe.h')
-rw-r--r--drivers/net/ethernet/intel/ixgbe/ixgbe.h15
1 files changed, 8 insertions, 7 deletions
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
index eb5928228670..b9623e9ea895 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
@@ -77,17 +77,18 @@
#define IXGBE_MAX_FCPAUSE 0xFFFF
/* Supported Rx Buffer Sizes */
-#define IXGBE_RXBUFFER_512 512 /* Used for packet split */
+#define IXGBE_RXBUFFER_256 256 /* Used for skb receive header */
#define IXGBE_MAX_RXBUFFER 16384 /* largest size for a single descriptor */
/*
- * NOTE: netdev_alloc_skb reserves up to 64 bytes, NET_IP_ALIGN mans we
- * reserve 2 more, and skb_shared_info adds an additional 384 bytes more,
- * this adds up to 512 bytes of extra data meaning the smallest allocation
- * we could have is 1K.
- * i.e. RXBUFFER_512 --> size-1024 slab
+ * NOTE: netdev_alloc_skb reserves up to 64 bytes, NET_IP_ALIGN means we
+ * reserve 64 more, and skb_shared_info adds an additional 320 bytes more,
+ * this adds up to 448 bytes of extra data.
+ *
+ * Since netdev_alloc_skb now allocates a page fragment we can use a value
+ * of 256 and the resultant skb will have a truesize of 960 or less.
*/
-#define IXGBE_RX_HDR_SIZE IXGBE_RXBUFFER_512
+#define IXGBE_RX_HDR_SIZE IXGBE_RXBUFFER_256
#define MAXIMUM_ETHERNET_VLAN_SIZE (ETH_FRAME_LEN + ETH_FCS_LEN + VLAN_HLEN)