[3/4] bench-strncmp.c: Add workloads on page boundary

Message ID 20200612201056.228614-3-hjl.tools@gmail.com
State New
Headers show
Series
  • [1/4] strncmp: Add a testcase for page boundary [BZ #25933]
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Commit Message

H.J. Lu via Libc-alpha June 12, 2020, 8:10 p.m.
Add strncmp workloads on page boundary.
---
 benchtests/bench-strncmp.c | 117 +++++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)

-- 
2.26.2

Comments

H.J. Lu via Libc-alpha Sept. 24, 2020, 12:46 a.m. | #1
On 6/12/20 4:10 PM, H.J. Lu via Libc-alpha wrote:
> Add strncmp workloads on page boundary.


This benchmark need some work.

Please post v2.

> ---

>  benchtests/bench-strncmp.c | 117 +++++++++++++++++++++++++++++++++++++

>  1 file changed, 117 insertions(+)

> 

> diff --git a/benchtests/bench-strncmp.c b/benchtests/bench-strncmp.c

> index 95a59c9465..065c7e7789 100644

> --- a/benchtests/bench-strncmp.c

> +++ b/benchtests/bench-strncmp.c

> @@ -27,6 +27,7 @@

>  

>  #ifdef WIDE

>  # define L(str) L##str

> +# define STRDUP wcsdup


OK.

>  # define SIMPLE_STRNCMP simple_wcsncmp

>  

>  /* Wcsncmp uses signed semantics for comparison, not unsigned.

> @@ -48,6 +49,7 @@ simple_wcsncmp (const CHAR *s1, const CHAR *s2, size_t n)

>  

>  #else

>  # define L(str) str

> +# define STRDUP strdup


OK.

>  # define SIMPLE_STRNCMP simple_strncmp

>  

>  /* Strncmp uses unsigned semantics for comparison.  */

> @@ -190,6 +192,118 @@ do_test (json_ctx_t *json_ctx, size_t align1, size_t align2, size_t len, size_t

>    json_element_object_end (json_ctx);

>  }

>  

> +static void

> +do_test_page_boundary_1 (json_ctx_t *json_ctx, CHAR *s1, CHAR *s2,


Rename to "do_one_test_page_boundary"

> +			 size_t align1, size_t align2, size_t len,

> +			 size_t n, int exp_result)

> +{

> +  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_array_begin (json_ctx, "timings");

> +  FOR_EACH_IMPL (impl, 0)

> +    do_one_test (json_ctx, impl, s1, s2, n, exp_result);

> +  json_array_end (json_ctx);

> +  json_element_object_end (json_ctx);


OK.

> +}

> +



Add a comment:

/* To trigger bug 25933 we need a size that is equal to the
   vector length times 4. In the case of AVX2 for Intel we
   need 32 * 4. We make this test generic and run it for all
   architectures as additional boundary testing for such
   related algorithms.  */

> +static void

> +do_test_page_boundary (json_ctx_t *json_ctx)


OK.

> +{

> +  size_t size = 32 * 4;

> +  size_t len;

> +  CHAR *s1 = (CHAR *) (buf1 + (BUF1PAGES - 1) * page_size);

> +  CHAR *s2 = (CHAR *) (buf2 + (BUF1PAGES - 1) * page_size);

> +  int exp_result;

> +

> +  memset (s1, 'a', page_size);

> +  memset (s2, 'a', page_size);

> +

> +  s1[(page_size / CHARBYTES) - 1] = (CHAR) 0;

> +


Add comment:

/* Iterate over a size that is just below where we expect
   the bug to trigger up to the size we expect will trigger
   the bug e.g. [99-128].  Likewise iterate the start of
   two strings between 30 and 31 bytes away from the
   boundary to simulate alignment changes.  */

> +  for (size_t s = 99; s <= size; s++)

> +    for (size_t s1a = 31; s1a < 32; s1a++)


Please make s1a iterate over [30,32) like s2a.

> +      for (size_t s2a = 30; s2a < 32; s2a++)

> +	{

> +	  size_t align1 = (page_size / CHARBYTES - s) - s1a;

> +	  size_t align2 = (page_size / CHARBYTES - s) - s2a;

> +	  CHAR *s1p = s1 + align1;

> +	  CHAR *s2p = s2 + align2;

> +	  len = (page_size / CHARBYTES) - 1 - align1;

> +	  exp_result = SIMPLE_STRNCMP (s1p, s2p, s);

> +	  do_test_page_boundary_1 (json_ctx, s1p, s2p, align1, align2,

> +				   len, s, exp_result);

> +	}

> +}

> +

> +static void

> +do_page_test (json_ctx_t *json_ctx, size_t offset1, size_t offset2,


Rename to do_one_test_page()

> +	      CHAR *s2)

> +{

> +  CHAR *s1;

> +  int exp_result;

> +

> +  if (offset1 * CHARBYTES  >= page_size

> +      || offset2 * CHARBYTES >= page_size)

> +    return;


OK. Nothing bigger than a page size because we only have one page to work within.

> +

> +  s1 = (CHAR *) buf1;

> +  s1 += offset1;

> +  s2 += offset2;

> +

> +  size_t len = (page_size / CHARBYTES) - offset1;

> +

> +  exp_result= *s1;

> +

> +  json_element_object_begin (json_ctx);

> +  json_attr_uint (json_ctx, "strlen", (double) len);

> +  json_attr_uint (json_ctx, "len", (double) page_size);

> +  json_attr_uint (json_ctx, "align1", (double) offset1);

> +  json_attr_uint (json_ctx, "align2", (double) offset2);

> +  json_array_begin (json_ctx, "timings");

> +  {

> +    FOR_EACH_IMPL (impl, 0)

> +      do_one_test (json_ctx, impl, s1, s2, page_size, -exp_result);

> +  }

> +  json_array_end (json_ctx);

> +  json_element_object_end (json_ctx);

> +

> +  json_element_object_begin (json_ctx);

> +  json_attr_uint (json_ctx, "strlen", (double) len);

> +  json_attr_uint (json_ctx, "len", (double) page_size);

> +  json_attr_uint (json_ctx, "align1", (double) offset1);

> +  json_attr_uint (json_ctx, "align2", (double) offset2);

> +  json_array_begin (json_ctx, "timings");

> +  {

> +    FOR_EACH_IMPL (impl, 0)

> +      do_one_test (json_ctx, impl, s1, s2, page_size, exp_result);

> +  }

> +  json_array_end (json_ctx);

> +  json_element_object_end (json_ctx);

> +}


OK.

> +

> +static void

> +do_test_page (json_ctx_t *json_ctx)

> +{

> +  size_t i;

> +  CHAR *s1, *s2;

> +

> +  s1 = (CHAR *) buf1;

> +  for (i = 0; i < (page_size / CHARBYTES) - 1; i++)

> +    s1[i] = 23;


Add a comment for this magic fill number.

> +  s1[i] = 0;

> +

> +  s2 = STRDUP (s1);

> +

> +  for (i = 0; i < 64; ++i)


Add a comment for these magic numbers.

> +    do_page_test (json_ctx, (3988 / CHARBYTES) + i,

> +		  (2636 / CHARBYTES), s2);


Call do_one_test_page()

> +

> +  free (s2);

> +}

> +

>  int

>  test_main (void)

>  {

> @@ -267,6 +381,9 @@ test_main (void)

>        do_test_limit (&json_ctx, 0, 0, 15 - i, 16 - i, 255, -1);

>      }

>  

> +  do_test_page_boundary (&json_ctx);

> +  do_test_page (&json_ctx);


OK.

> +

>    json_array_end (&json_ctx);

>    json_attr_object_end (&json_ctx);

>    json_attr_object_end (&json_ctx);

> 



-- 
Cheers,
Carlos.

Patch

diff --git a/benchtests/bench-strncmp.c b/benchtests/bench-strncmp.c
index 95a59c9465..065c7e7789 100644
--- a/benchtests/bench-strncmp.c
+++ b/benchtests/bench-strncmp.c
@@ -27,6 +27,7 @@ 
 
 #ifdef WIDE
 # define L(str) L##str
+# define STRDUP wcsdup
 # define SIMPLE_STRNCMP simple_wcsncmp
 
 /* Wcsncmp uses signed semantics for comparison, not unsigned.
@@ -48,6 +49,7 @@  simple_wcsncmp (const CHAR *s1, const CHAR *s2, size_t n)
 
 #else
 # define L(str) str
+# define STRDUP strdup
 # define SIMPLE_STRNCMP simple_strncmp
 
 /* Strncmp uses unsigned semantics for comparison.  */
@@ -190,6 +192,118 @@  do_test (json_ctx_t *json_ctx, size_t align1, size_t align2, size_t len, size_t
   json_element_object_end (json_ctx);
 }
 
+static void
+do_test_page_boundary_1 (json_ctx_t *json_ctx, CHAR *s1, CHAR *s2,
+			 size_t align1, size_t align2, size_t len,
+			 size_t n, int exp_result)
+{
+  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_array_begin (json_ctx, "timings");
+  FOR_EACH_IMPL (impl, 0)
+    do_one_test (json_ctx, impl, s1, s2, n, exp_result);
+  json_array_end (json_ctx);
+  json_element_object_end (json_ctx);
+}
+
+static void
+do_test_page_boundary (json_ctx_t *json_ctx)
+{
+  size_t size = 32 * 4;
+  size_t len;
+  CHAR *s1 = (CHAR *) (buf1 + (BUF1PAGES - 1) * page_size);
+  CHAR *s2 = (CHAR *) (buf2 + (BUF1PAGES - 1) * page_size);
+  int exp_result;
+
+  memset (s1, 'a', page_size);
+  memset (s2, 'a', page_size);
+
+  s1[(page_size / CHARBYTES) - 1] = (CHAR) 0;
+
+  for (size_t s = 99; s <= size; s++)
+    for (size_t s1a = 31; s1a < 32; s1a++)
+      for (size_t s2a = 30; s2a < 32; s2a++)
+	{
+	  size_t align1 = (page_size / CHARBYTES - s) - s1a;
+	  size_t align2 = (page_size / CHARBYTES - s) - s2a;
+	  CHAR *s1p = s1 + align1;
+	  CHAR *s2p = s2 + align2;
+	  len = (page_size / CHARBYTES) - 1 - align1;
+	  exp_result = SIMPLE_STRNCMP (s1p, s2p, s);
+	  do_test_page_boundary_1 (json_ctx, s1p, s2p, align1, align2,
+				   len, s, exp_result);
+	}
+}
+
+static void
+do_page_test (json_ctx_t *json_ctx, size_t offset1, size_t offset2,
+	      CHAR *s2)
+{
+  CHAR *s1;
+  int exp_result;
+
+  if (offset1 * CHARBYTES  >= page_size
+      || offset2 * CHARBYTES >= page_size)
+    return;
+
+  s1 = (CHAR *) buf1;
+  s1 += offset1;
+  s2 += offset2;
+
+  size_t len = (page_size / CHARBYTES) - offset1;
+
+  exp_result= *s1;
+
+  json_element_object_begin (json_ctx);
+  json_attr_uint (json_ctx, "strlen", (double) len);
+  json_attr_uint (json_ctx, "len", (double) page_size);
+  json_attr_uint (json_ctx, "align1", (double) offset1);
+  json_attr_uint (json_ctx, "align2", (double) offset2);
+  json_array_begin (json_ctx, "timings");
+  {
+    FOR_EACH_IMPL (impl, 0)
+      do_one_test (json_ctx, impl, s1, s2, page_size, -exp_result);
+  }
+  json_array_end (json_ctx);
+  json_element_object_end (json_ctx);
+
+  json_element_object_begin (json_ctx);
+  json_attr_uint (json_ctx, "strlen", (double) len);
+  json_attr_uint (json_ctx, "len", (double) page_size);
+  json_attr_uint (json_ctx, "align1", (double) offset1);
+  json_attr_uint (json_ctx, "align2", (double) offset2);
+  json_array_begin (json_ctx, "timings");
+  {
+    FOR_EACH_IMPL (impl, 0)
+      do_one_test (json_ctx, impl, s1, s2, page_size, exp_result);
+  }
+  json_array_end (json_ctx);
+  json_element_object_end (json_ctx);
+}
+
+static void
+do_test_page (json_ctx_t *json_ctx)
+{
+  size_t i;
+  CHAR *s1, *s2;
+
+  s1 = (CHAR *) buf1;
+  for (i = 0; i < (page_size / CHARBYTES) - 1; i++)
+    s1[i] = 23;
+  s1[i] = 0;
+
+  s2 = STRDUP (s1);
+
+  for (i = 0; i < 64; ++i)
+    do_page_test (json_ctx, (3988 / CHARBYTES) + i,
+		  (2636 / CHARBYTES), s2);
+
+  free (s2);
+}
+
 int
 test_main (void)
 {
@@ -267,6 +381,9 @@  test_main (void)
       do_test_limit (&json_ctx, 0, 0, 15 - i, 16 - i, 255, -1);
     }
 
+  do_test_page_boundary (&json_ctx);
+  do_test_page (&json_ctx);
+
   json_array_end (&json_ctx);
   json_attr_object_end (&json_ctx);
   json_attr_object_end (&json_ctx);