V2 [PATCH] bench-strncmp.c: Add workloads on page boundary
Commit Message
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
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>
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(+)
@@ -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