diff mbox series

V2 [PATCH] bench-strncmp.c: Add workloads on page boundary

Message ID CAMe9rOor2LojB7CkYH3Szd4_wY2ApAVqnRJXwxUNF+6gyddAMw@mail.gmail.com
State New
Headers show
Series V2 [PATCH] bench-strncmp.c: Add workloads on page boundary | expand

Commit Message

H.J. Lu Sept. 24, 2020, 3:13 p.m. UTC
On Wed, Sep 23, 2020 at 5:46 PM Carlos O'Donell <carlos@redhat.com> wrote:
>
> 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"

Done.

> > +                      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.  */

Done.

> > +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.  */

Done.

> > +  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.

Done.

> > +      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()

Done.

> > +           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.

Done.

> > +  s1[i] = 0;
> > +
> > +  s2 = STRDUP (s1);
> > +
> > +  for (i = 0; i < 64; ++i)
>
> Add a comment for these magic numbers.

Done.

> > +    do_page_test (json_ctx, (3988 / CHARBYTES) + i,
> > +               (2636 / CHARBYTES), s2);
>
> Call do_one_test_page()

Done.

> > +
> > +  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);
> >
>

Here is the updated patch.  OK for master?

Thanks.

Comments

Carlos O'Donell Sept. 24, 2020, 5:30 p.m. UTC | #1
On 9/24/20 11:13 AM, H.J. Lu wrote:
> Here is the updated patch.  OK for master?

Is OK for master. Though my preference is for more verbosity on the
exactly numbers used in do_test_page() e.g. why 108 or 1460.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
diff mbox series

Patch

From 70919738604840c387e342aaea4e6b13f8a16043 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Thu, 11 Jun 2020 08:52:42 -0700
Subject: [PATCH] bench-strncmp.c: Add workloads on page boundary

Add strncmp workloads on page boundary.
---
 benchtests/bench-strncmp.c | 128 +++++++++++++++++++++++++++++++++++++
 1 file changed, 128 insertions(+)

diff --git a/benchtests/bench-strncmp.c b/benchtests/bench-strncmp.c
index 95a59c9465..b307f0c555 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 +192,129 @@  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_one_test_page_boundary (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)
+{
+  /* 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.  */
+  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;
+
+  /* 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 = 30; 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_one_test_page_boundary (json_ctx, s1p, s2p, align1, align2,
+				     len, s, exp_result);
+	}
+}
+
+static void
+do_one_test_page (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;
+  /* Fill buf1 with 23. */
+  for (i = 0; i < (page_size / CHARBYTES) - 1; i++)
+    s1[i] = 23;
+  s1[i] = 0;
+
+  /* Make a copy of buf1.  */
+  s2 = STRDUP (s1);
+
+  /* Test should terminate within the page boundary.  */
+  for (i = 0; i < (108 / CHARBYTES); ++i)
+    do_one_test_page (json_ctx, ((page_size - 108) / CHARBYTES) + i,
+		      ((page_size - 1460) / CHARBYTES), s2);
+
+  free (s2);
+}
+
 int
 test_main (void)
 {
@@ -267,6 +392,9 @@  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);
-- 
2.26.2