Add a bihash prefetchable bucket-level cache

According to Maciek, the easiest way to leverage the csit "performance
trend" job is to actually merge the patch once verified. Manual
testing indicates that the patch improves l2 path performance. Other
use-cases are TBD. It's possible that we'll need to back out the patch
depending on what happens.

Change-Id: Ic0a0363de35ef9be953ad7709c57c3936b73fd5a
Signed-off-by: Dave Barach <dave@barachs.net>

1 files changed, 55 insertions, 6 deletions

diff --git a/src/vppinfra/test_bihash_template.c b/src/vppinfra/test_bihash_template.c
index 1e262430803..589c815dff1 100644
--- a/src/vppinfra/test_bihash_template.c
+++ b/src/vppinfra/test_bihash_template.c
@@ -237,11 +237,44 @@ test_bihash (test_main_t * tm)
 }
 
 clib_error_t *
+test_bihash_cache (test_main_t * tm)
+{
+  u32 lru;
+  BVT (clib_bihash_bucket) _b, *b = &_b;
+
+  BV (clib_bihash_reset_cache) (b);
+
+  fformat (stdout, "Initial LRU config: %U\n", BV (format_bihash_lru), b);
+
+  BV (clib_bihash_update_lru_not_inline) (b, 3);
+
+  fformat (stdout, "use slot 3, LRU config: %U\n", BV (format_bihash_lru), b);
+
+  BV (clib_bihash_update_lru) (b, 1);
+
+  fformat (stdout, "use slot 1 LRU config: %U\n", BV (format_bihash_lru), b);
+
+  lru = BV (clib_bihash_get_lru) (b);
+
+  fformat (stdout, "least-recently-used is %d\n", lru);
+
+  BV (clib_bihash_update_lru) (b, 4);
+
+  fformat (stdout, "use slot 4 LRU config: %U\n", BV (format_bihash_lru), b);
+
+  lru = BV (clib_bihash_get_lru) (b);
+
+  fformat (stdout, "least-recently-used is %d\n", lru);
+
+  return 0;
+}
+
+clib_error_t *
 test_bihash_main (test_main_t * tm)
 {
   unformat_input_t *i = tm->input;
   clib_error_t *error;
-  int test_vec64 = 0;
+  int which = 0;
 
   while (unformat_check_input (i) != UNFORMAT_END_OF_INPUT)
     {
@@ -261,7 +294,10 @@ test_bihash_main (test_main_t * tm)
       else if (unformat (i, "search %d", &tm->search_iter))
 	;
       else if (unformat (i, "vec64"))
-	test_vec64 = 1;
+	which = 1;
+      else if (unformat (i, "cache"))
+	which = 2;
+
       else if (unformat (i, "verbose"))
 	tm->verbose = 1;
       else
@@ -269,10 +305,23 @@ test_bihash_main (test_main_t * tm)
 				  format_unformat_error, i);
     }
 
-  if (test_vec64)
-    error = test_bihash_vec64 (tm);
-  else
-    error = test_bihash (tm);
+  switch (which)
+    {
+    case 0:
+      error = test_bihash (tm);
+      break;
+
+    case 1:
+      error = test_bihash_vec64 (tm);
+      break;
+
+    case 2:
+      error = test_bihash_cache (tm);
+      break;
+
+    default:
+      return clib_error_return (0, "no such test?");
+    }
 
   return error;
 }