fib: Compiile time option to use 8-8-8-8 stride tries for FIB rather

than 16-8-8-8

Type: feature

the memory trade-off is:

for 8-8-8-8 tries

DBGvpp# sh ip fib mtrie mem
ipv4-VRF:0 mtrie:8068 hash:3499
totals: mtrie:8068 hash:3499 all:11567

for 16-8-8

DBGvpp# sh ip fib mtrie mem
ipv4-VRF:0 mtrie:333056 hash:3499
totals: mtrie:333056 hash:3499 all:336555

Signed-off-by: Neale Ranns <neale@graphiant.com>
Change-Id: I5271a4322d786de6e47613cff9bd432762dbed2a

2 files changed, 123 insertions, 0 deletions

diff --git a/src/vnet/CMakeLists.txt b/src/vnet/CMakeLists.txt
index df23738013d..66a4abc3a41 100644
--- a/src/vnet/CMakeLists.txt
+++ b/src/vnet/CMakeLists.txt
@@ -16,6 +16,8 @@ unset(VNET_HEADERS)
 unset(VNET_API_FILES)
 unset(VNET_MULTIARCH_SOURCES)
 
+option(VPP_IP_FIB_MTRIE_16 "IP FIB's MTRIE Stride is 16-8-8 (if not set it's 8-8-8-8)" ON)
+
 ##############################################################################
 # Generic stuff
 ##############################################################################
diff --git a/src/vnet/fib/ip4_fib.h b/src/vnet/fib/ip4_fib.h
index 0f6911dd3aa..65fc7775cc4 100644
--- a/src/vnet/fib/ip4_fib.h
+++ b/src/vnet/fib/ip4_fib.h
@@ -37,9 +37,13 @@
 #include <vnet/fib/ip4_fib_8.h>
 #include <vnet/fib/ip4_fib_16.h>
 
+// for the VPP_IP_FIB_MTRIE_16 definition
+#include <vpp/vnet/config.h>
+
 /**
  * the FIB module uses the 16-8-8 stride trie
  */
+#ifdef VPP_IP_FIB_MTRIE_16
 typedef ip4_fib_16_t ip4_fib_t;
 
 #define ip4_fibs ip4_fib_16s
@@ -57,6 +61,26 @@ typedef ip4_fib_16_t ip4_fib_t;
 #define ip4_mtrie_memory_usage ip4_mtrie_16_memory_usage
 #define format_ip4_mtrie format_ip4_mtrie_16
 
+#else
+typedef ip4_fib_8_t ip4_fib_t;
+
+#define ip4_fibs ip4_fib_8s
+#define ip4_fib_table_lookup ip4_fib_8_table_lookup
+#define ip4_fib_table_lookup_exact_match ip4_fib_8_table_lookup_exact_match
+#define ip4_fib_table_entry_remove ip4_fib_8_table_entry_remove
+#define ip4_fib_table_entry_insert ip4_fib_8_table_entry_insert
+#define ip4_fib_table_fwding_dpo_update ip4_fib_8_table_fwding_dpo_update
+#define ip4_fib_table_fwding_dpo_remove ip4_fib_8_table_fwding_dpo_remove
+#define ip4_fib_table_lookup_lb ip4_fib_8_table_lookup_lb
+#define ip4_fib_table_walk ip4_fib_8_table_walk
+#define ip4_fib_table_sub_tree_walk ip4_fib_8_table_sub_tree_walk
+#define ip4_fib_table_init ip4_fib_8_table_init
+#define ip4_fib_table_free ip4_fib_8_table_free
+#define ip4_mtrie_memory_usage ip4_mtrie_8_memory_usage
+#define format_ip4_mtrie format_ip4_mtrie_8
+
+#endif
+
 /**
  * @brief Get the FIB at the given index
  */
@@ -108,6 +132,7 @@ u32 ip4_fib_index_from_table_id (u32 table_id)
 
 extern u32 ip4_fib_table_get_index_for_sw_if_index(u32 sw_if_index);
 
+#ifdef VPP_IP_FIB_MTRIE_16
 always_inline index_t
 ip4_fib_forwarding_lookup (u32 fib_index,
                            const ip4_address_t * addr)
@@ -192,4 +217,100 @@ ip4_fib_forwarding_lookup_x4 (u32 fib_index0,
     *lb3 = ip4_mtrie_leaf_get_adj_index(leaf[3]);
 }
 
+#else
+
+always_inline index_t
+ip4_fib_forwarding_lookup (u32 fib_index,
+                           const ip4_address_t * addr)
+{
+    ip4_mtrie_leaf_t leaf;
+    ip4_mtrie_8_t * mtrie;
+
+    mtrie = &ip4_fib_get(fib_index)->mtrie;
+
+    leaf = ip4_mtrie_8_lookup_step_one (mtrie, addr);
+    leaf = ip4_mtrie_8_lookup_step (leaf, addr, 1);
+    leaf = ip4_mtrie_8_lookup_step (leaf, addr, 2);
+    leaf = ip4_mtrie_8_lookup_step (leaf, addr, 3);
+
+    return (ip4_mtrie_leaf_get_adj_index(leaf));
+}
+
+static_always_inline void
+ip4_fib_forwarding_lookup_x2 (u32 fib_index0,
+                              u32 fib_index1,
+                              const ip4_address_t * addr0,
+                              const ip4_address_t * addr1,
+                              index_t *lb0,
+                              index_t *lb1)
+{
+    ip4_mtrie_leaf_t leaf[2];
+    ip4_mtrie_8_t * mtrie[2];
+
+    mtrie[0] = &ip4_fib_get(fib_index0)->mtrie;
+    mtrie[1] = &ip4_fib_get(fib_index1)->mtrie;
+
+    leaf[0] = ip4_mtrie_8_lookup_step_one (mtrie[0], addr0);
+    leaf[1] = ip4_mtrie_8_lookup_step_one (mtrie[1], addr1);
+    leaf[0] = ip4_mtrie_8_lookup_step (leaf[0], addr0, 1);
+    leaf[1] = ip4_mtrie_8_lookup_step (leaf[1], addr1, 1);
+    leaf[0] = ip4_mtrie_8_lookup_step (leaf[0], addr0, 2);
+    leaf[1] = ip4_mtrie_8_lookup_step (leaf[1], addr1, 2);
+    leaf[0] = ip4_mtrie_8_lookup_step (leaf[0], addr0, 3);
+    leaf[1] = ip4_mtrie_8_lookup_step (leaf[1], addr1, 3);
+
+    *lb0 = ip4_mtrie_leaf_get_adj_index(leaf[0]);
+    *lb1 = ip4_mtrie_leaf_get_adj_index(leaf[1]);
+}
+
+static_always_inline void
+ip4_fib_forwarding_lookup_x4 (u32 fib_index0,
+                              u32 fib_index1,
+                              u32 fib_index2,
+                              u32 fib_index3,
+                              const ip4_address_t * addr0,
+                              const ip4_address_t * addr1,
+                              const ip4_address_t * addr2,
+                              const ip4_address_t * addr3,
+                              index_t *lb0,
+                              index_t *lb1,
+                              index_t *lb2,
+                              index_t *lb3)
+{
+    ip4_mtrie_leaf_t leaf[4];
+    ip4_mtrie_8_t * mtrie[4];
+
+    mtrie[0] = &ip4_fib_get(fib_index0)->mtrie;
+    mtrie[1] = &ip4_fib_get(fib_index1)->mtrie;
+    mtrie[2] = &ip4_fib_get(fib_index2)->mtrie;
+    mtrie[3] = &ip4_fib_get(fib_index3)->mtrie;
+
+    leaf[0] = ip4_mtrie_8_lookup_step_one (mtrie[0], addr0);
+    leaf[1] = ip4_mtrie_8_lookup_step_one (mtrie[1], addr1);
+    leaf[2] = ip4_mtrie_8_lookup_step_one (mtrie[2], addr2);
+    leaf[3] = ip4_mtrie_8_lookup_step_one (mtrie[3], addr3);
+
+    leaf[0] = ip4_mtrie_8_lookup_step (leaf[0], addr0, 1);
+    leaf[1] = ip4_mtrie_8_lookup_step (leaf[1], addr1, 1);
+    leaf[2] = ip4_mtrie_8_lookup_step (leaf[2], addr2, 1);
+    leaf[3] = ip4_mtrie_8_lookup_step (leaf[3], addr3, 1);
+
+    leaf[0] = ip4_mtrie_8_lookup_step (leaf[0], addr0, 2);
+    leaf[1] = ip4_mtrie_8_lookup_step (leaf[1], addr1, 2);
+    leaf[2] = ip4_mtrie_8_lookup_step (leaf[2], addr2, 2);
+    leaf[3] = ip4_mtrie_8_lookup_step (leaf[3], addr3, 2);
+
+    leaf[0] = ip4_mtrie_8_lookup_step (leaf[0], addr0, 3);
+    leaf[1] = ip4_mtrie_8_lookup_step (leaf[1], addr1, 3);
+    leaf[2] = ip4_mtrie_8_lookup_step (leaf[2], addr2, 3);
+    leaf[3] = ip4_mtrie_8_lookup_step (leaf[3], addr3, 3);
+
+    *lb0 = ip4_mtrie_leaf_get_adj_index(leaf[0]);
+    *lb1 = ip4_mtrie_leaf_get_adj_index(leaf[1]);
+    *lb2 = ip4_mtrie_leaf_get_adj_index(leaf[2]);
+    *lb3 = ip4_mtrie_leaf_get_adj_index(leaf[3]);
+}
+
+#endif
+
 #endif