bond: performance harvesting [VPP-1298]

- hash is great. But it is a bit too slow for the DP. Use direct array indexing
to quickly retrieve the slave interface.
- the algorithm used by flow hash is great. But it is a bit too slow for the DP.
Use l2_hash_hash() extracted from lb_hash.h which ECMP is using. It makes use
of intrinsic crc32 instruction set.
- shortcut modulo arithmetic when the operand is 2**x (where x up to 4) to
avoid division instruction.
- special case for link count == 1 in bond_tx_fn()
- use clib_mem_unaligned to access data for the packet to avoid alignment error
- Fix some typos for packet tracing.

Change-Id: I8eae3ad497061c5473aa675ba894ee0211120d25
Signed-off-by: Steven <sluong@cisco.com>
(cherry picked from commit 0d88301a576191a0e330e539cf1dcb3837ee1bf6)

1 files changed, 11 insertions, 7 deletions

diff --git a/src/vnet/bonding/node.h b/src/vnet/bonding/node.h
index 3a01abe2226..5c6ff32ac4a 100644
--- a/src/vnet/bonding/node.h
+++ b/src/vnet/bonding/node.h
@@ -31,6 +31,9 @@
 #define MIN(x,y) (((x)<(y))?(x):(y))
 #endif
 
+#define BOND_MODULO_SHORTCUT(a) \
+  (((a) == 2) || ((a) == 4) || ((a) == 8) || ((a) == 16))
+
 #define foreach_bond_mode	    \
   _ (1, ROUND_ROBIN, "round-robin") \
   _ (2, ACTIVE_BACKUP, "active-backup") \
@@ -289,9 +292,6 @@ typedef struct
   /* pool of lacp neighbors */
   slave_if_t *neighbors;
 
-  /* rapidly find a neighbor by vlib software interface index */
-  uword *neighbor_by_sw_if_index;
-
   /* rapidly find a bond by vlib software interface index */
   uword *bond_by_sw_if_index;
 
@@ -303,6 +303,8 @@ typedef struct
   u8 lacp_plugin_loaded;
 
   lacp_enable_disable_func lacp_enable_disable;
+
+  uword *slave_by_sw_if_index;
 } bond_main_t;
 
 /* bond packet trace capture */
@@ -439,13 +441,15 @@ bond_get_slave_by_sw_if_index (u32 sw_if_index)
 {
   bond_main_t *bm = &bond_main;
   slave_if_t *sif = 0;
-  uword *p;
+  uword p;
 
-  p = hash_get (bm->neighbor_by_sw_if_index, sw_if_index);
-  if (p)
+  if (sw_if_index < vec_len (bm->slave_by_sw_if_index))
     {
-      sif = pool_elt_at_index (bm->neighbors, p[0]);
+      p = bm->slave_by_sw_if_index[sw_if_index];
+      if (p)
+	sif = pool_elt_at_index (bm->neighbors, p >> 1);
     }
+
   return sif;
 }