fib: improve ipv6 fib scaling

VPP IPv6 FIB relies on 2 bihash for all its VRFs: 1 for control plane
and one for data plane. Because of that, control plane VRF walks
time grows with the number of VRFs as it has to go through all the VRFs.
In order to improve control plane performance with large number of VRFs,
the control plane data structure is changed from a global bihash to a
per-VRF hashtable, similarly to IPv4. Contrary to IPv4, there is only 1
hashtable per VRF and not 1 hashtable per prefix-length per VRF, which
is a compromise between memory consumption and single VRF scaling.

Type: improvement

Change-Id: Ib738a44adb88e46c95c4c62c853ee1f1392c7187
Signed-off-by: Benoît Ganne <bganne@cisco.com>
diff --git a/src/vnet/fib/ip6_fib.h b/src/vnet/fib/ip6_fib.h
index 706bebb..80d56b1 100644
--- a/src/vnet/fib/ip6_fib.h
+++ b/src/vnet/fib/ip6_fib.h
@@ -26,36 +26,15 @@
 #include <vppinfra/bihash_template.h>
 
 /*
- * Default size of the ip6 fib hash table
+ * Default size of the ip6 fib forwarding hash table
  */
 #define IP6_FIB_DEFAULT_HASH_NUM_BUCKETS (64 * 1024)
 #define IP6_FIB_DEFAULT_HASH_MEMORY_SIZE (32<<20)
 
 /**
- * Enumeration of the FIB table instance types
+ * A representation the forwarding IP6 table
  */
-typedef enum ip6_fib_table_instance_type_t_
-{
-    /**
-     * This table stores the routes that are used to forward traffic.
-     * The key is the prefix, the result the adjacency to forward on.
-     */
-  IP6_FIB_TABLE_FWDING,
-    /**
-     * The table that stores ALL routes learned by the DP.
-     * Some of these routes may not be ready to install in forwarding
-     * at a given time.
-     * The key in this table is the prefix, the result is the fib_entry_t
-     */
-  IP6_FIB_TABLE_NON_FWDING,
-} ip6_fib_table_instance_type_t;
-
-#define IP6_FIB_NUM_TABLES (IP6_FIB_TABLE_NON_FWDING+1)
-
-/**
- * A representation of a single IP6 table
- */
-typedef struct ip6_fib_table_instance_t_
+typedef struct ip6_fib_fwding_table_instance_t_
 {
   /* The hash table */
   clib_bihash_24_8_t ip6_hash;
@@ -64,12 +43,12 @@
   uword *non_empty_dst_address_length_bitmap;
   u8 *prefix_lengths_in_search_order;
   i32 dst_address_length_refcounts[129];
-} ip6_fib_table_instance_t;
+} ip6_fib_fwding_table_instance_t;
 
 /**
  * The two FIB tables; fwding and non-fwding
  */
-extern ip6_fib_table_instance_t ip6_fib_table[IP6_FIB_NUM_TABLES];
+extern ip6_fib_fwding_table_instance_t ip6_fib_fwding_table;
 
 extern fib_node_index_t ip6_fib_table_lookup(u32 fib_index,
 					     const ip6_address_t *addr,
@@ -115,13 +94,13 @@
 ip6_fib_table_fwding_lookup (u32 fib_index,
                              const ip6_address_t * dst)
 {
-    ip6_fib_table_instance_t *table;
+    ip6_fib_fwding_table_instance_t *table;
     clib_bihash_kv_24_8_t kv, value;
     int i, len;
     int rv;
     u64 fib;
 
-    table = &ip6_fib_table[IP6_FIB_TABLE_FWDING];
+    table = &ip6_fib_fwding_table;
     len = vec_len (table->prefix_lengths_in_search_order);
 
     kv.key[0] = dst->as_u64[0];
@@ -230,6 +209,7 @@
 }
 
 extern u32 ip6_fib_table_get_index_for_sw_if_index(u32 sw_if_index);
+extern void ip6_fib_table_show (vlib_main_t *vm, fib_table_t *fib_table, int summary);
 
 #endif