vxlan: improve encap performance

1. For vxlan, prefetching one cacheline is enough.
2. Reduce vlib_increment_combined_counter functtion calling
if possible.

Change-Id: If3a72ac40c8988caaf0d5915b695f86d799f15a9
Signed-off-by: Zhiyong Yang <zhiyong.yang@intel.com>

diff --git a/src/vnet/vxlan/encap.c b/src/vnet/vxlan/encap.c
index c34b0e6..fdca425 100644 (file)
--- a/src/vnet/vxlan/encap.c
+++ b/src/vnet/vxlan/encap.c
@@ -116,8 +116,8 @@ vxlan_encap_inline (vlib_main_t * vm,
            vlib_prefetch_buffer_header (p2, LOAD);
            vlib_prefetch_buffer_header (p3, LOAD);
 
-           CLIB_PREFETCH (p2->data, 2*CLIB_CACHE_LINE_BYTES, LOAD);
-           CLIB_PREFETCH (p3->data, 2*CLIB_CACHE_LINE_BYTES, LOAD);
+           CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
+           CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, LOAD);
          }
 
          u32 bi0 = to_next[0] = from[0];
@@ -292,10 +292,18 @@ vxlan_encap_inline (vlib_main_t * vm,
                 udp1->checksum = 0xffff;
             }
 
+       if (sw_if_index0 == sw_if_index1)
+       {
+          vlib_increment_combined_counter (tx_counter, thread_index,
+              sw_if_index0, 2, len0 + len1);
+       }
+       else
+       {
           vlib_increment_combined_counter (tx_counter, thread_index,
               sw_if_index0, 1, len0);
           vlib_increment_combined_counter (tx_counter, thread_index,
               sw_if_index1, 1, len1);
+       }
           pkts_encapsulated += 2;
 
          if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))