From 70919738604840c387e342aaea4e6b13f8a16043 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" 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