benchtests: Add more coverage for strcmp and strncmp benchmarks

Add more small and medium sized tests for strcmp and strncmp.

As well for strcmp add option for more direct control of
alignment. Previously alignment was being pushed to the end of the
page. While this is the most difficult case to implement, it is far
from the common case and so shouldn't be the only benchmark.

Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>

1 files changed, 81 insertions, 29 deletions

diff --git a/benchtests/bench-strncmp.c b/benchtests/bench-strncmp.c
index b7a01fd..6673a53 100644
--- a/benchtests/bench-strncmp.c
+++ b/benchtests/bench-strncmp.c
@@ -150,43 +150,43 @@ do_test (json_ctx_t *json_ctx, size_t align1, size_t align2, size_t len, size_t
   if (n == 0)
     return;
 
-  align1 &= 63;
+  align1 &= getpagesize () - 1;
   if (align1 + (n + 1) * CHARBYTES >= page_size)
     return;
 
-  align2 &= 7;
+  align2 &= getpagesize () - 1;
   if (align2 + (n + 1) * CHARBYTES >= page_size)
     return;
 
   json_element_object_begin (json_ctx);
-  json_attr_uint (json_ctx, "strlen", (double) len);
-  json_attr_uint (json_ctx, "len", (double) n);
-  json_attr_uint (json_ctx, "align1", (double) align1);
-  json_attr_uint (json_ctx, "align2", (double) align2);
+  json_attr_uint (json_ctx, "strlen", (double)len);
+  json_attr_uint (json_ctx, "len", (double)n);
+  json_attr_uint (json_ctx, "align1", (double)align1);
+  json_attr_uint (json_ctx, "align2", (double)align2);
   json_array_begin (json_ctx, "timings");
 
   FOR_EACH_IMPL (impl, 0)
-    {
-      alloc_bufs ();
-      s1 = (CHAR *) (buf1 + align1);
-      s2 = (CHAR *) (buf2 + align2);
-
-      for (i = 0; i < n; i++)
-	s1[i] = s2[i] = 1 + (23 << ((CHARBYTES - 1) * 8)) * i % max_char;
-
-      s1[n] = 24 + exp_result;
-      s2[n] = 23;
-      s1[len] = 0;
-      s2[len] = 0;
-      if (exp_result < 0)
-	s2[len] = 32;
-      else if (exp_result > 0)
-	s1[len] = 64;
-      if (len >= n)
-	s2[n - 1] -= exp_result;
+  {
+    alloc_bufs ();
+    s1 = (CHAR *)(buf1 + align1);
+    s2 = (CHAR *)(buf2 + align2);
+
+    for (i = 0; i < n; i++)
+      s1[i] = s2[i] = 1 + (23 << ((CHARBYTES - 1) * 8)) * i % max_char;
+
+    s1[n] = 24 + exp_result;
+    s2[n] = 23;
+    s1[len] = 0;
+    s2[len] = 0;
+    if (exp_result < 0)
+      s2[len] = 32;
+    else if (exp_result > 0)
+      s1[len] = 64;
+    if (len >= n)
+      s2[n - 1] -= exp_result;
 
-      do_one_test (json_ctx, impl, s1, s2, n, exp_result);
-    }
+    do_one_test (json_ctx, impl, s1, s2, n, exp_result);
+  }
 
   json_array_end (json_ctx);
   json_element_object_end (json_ctx);
@@ -319,7 +319,8 @@ int
 test_main (void)
 {
   json_ctx_t json_ctx;
-  size_t i;
+  size_t i, j, len;
+  size_t pg_sz = getpagesize ();
 
   test_init ();
 
@@ -334,12 +335,12 @@ test_main (void)
 
   json_array_begin (&json_ctx, "ifuncs");
   FOR_EACH_IMPL (impl, 0)
-    json_element_string (&json_ctx, impl->name);
+  json_element_string (&json_ctx, impl->name);
   json_array_end (&json_ctx);
 
   json_array_begin (&json_ctx, "results");
 
-  for (i =0; i < 16; ++i)
+  for (i = 0; i < 16; ++i)
     {
       do_test (&json_ctx, 0, 0, 8, i, 127, 0);
       do_test (&json_ctx, 0, 0, 8, i, 127, -1);
@@ -361,6 +362,57 @@ test_main (void)
       do_test (&json_ctx, i, 3 * i, 8, i, 255, -1);
     }
 
+  for (len = 0; len <= 128; len += 64)
+    {
+      for (i = 1; i <= 8192;)
+        {
+          /* No page crosses.  */
+          do_test (&json_ctx, 0, 0, i, i + len, 127, 0);
+          do_test (&json_ctx, i * CHARBYTES, 0, i, i + len, 127, 0);
+          do_test (&json_ctx, 0, i * CHARBYTES, i, i + len, 127, 0);
+
+          /* False page crosses.  */
+          do_test (&json_ctx, pg_sz / 2, pg_sz / 2 - CHARBYTES, i, i + len,
+                   127, 0);
+          do_test (&json_ctx, pg_sz / 2 - CHARBYTES, pg_sz / 2, i, i + len,
+                   127, 0);
+
+          do_test (&json_ctx, pg_sz - (i * CHARBYTES), 0, i, i + len, 127,
+                   0);
+          do_test (&json_ctx, 0, pg_sz - (i * CHARBYTES), i, i + len, 127,
+                   0);
+
+          /* Real page cross.  */
+          for (j = 16; j < 128; j += 16)
+            {
+              do_test (&json_ctx, pg_sz - j, 0, i, i + len, 127, 0);
+              do_test (&json_ctx, 0, pg_sz - j, i, i + len, 127, 0);
+
+              do_test (&json_ctx, pg_sz - j, pg_sz - j / 2, i, i + len,
+                       127, 0);
+              do_test (&json_ctx, pg_sz - j / 2, pg_sz - j, i, i + len,
+                       127, 0);
+            }
+
+          if (i < 32)
+            {
+              ++i;
+            }
+          else if (i < 160)
+            {
+              i += 8;
+            }
+          else if (i < 256)
+            {
+              i += 32;
+            }
+          else
+            {
+              i *= 2;
+            }
+        }
+    }
+
   for (i = 1; i < 8; ++i)
     {
       do_test (&json_ctx, 0, 0, 8 << i, 16 << i, 127, 0);