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71ae86478e
This patch adds an optimized memset implementation for POWER8. For sizes from 0 to 255 bytes, a word/doubleword algorithm similar to POWER7 optimized one is used. For size higher than 255 two strategies are used: 1. If the constant is different than 0, the memory is written with altivec vector instruction; 2. If constant is 0, dbcz instructions are used. The loop is unrolled to clear 512 byte at time. Using vector instructions increases throughput considerable, with a double performance for sizes larger than 1024. The dcbz loops unrolls also shows performance improvement, by doubling throughput for sizes larger than 8192 bytes.
168 lines
3.4 KiB
C
168 lines
3.4 KiB
C
/* Measure memset functions.
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Copyright (C) 2013-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#define TEST_MAIN
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#ifdef TEST_BZERO
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# define TEST_NAME "bzero"
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#else
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# define TEST_NAME "memset"
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#endif
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#define MIN_PAGE_SIZE 131072
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#include "bench-string.h"
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char *simple_memset (char *, int, size_t);
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#ifdef TEST_BZERO
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typedef void (*proto_t) (char *, size_t);
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void simple_bzero (char *, size_t);
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void builtin_bzero (char *, size_t);
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IMPL (simple_bzero, 0)
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IMPL (builtin_bzero, 0)
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IMPL (bzero, 1)
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void
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simple_bzero (char *s, size_t n)
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{
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simple_memset (s, 0, n);
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}
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void
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builtin_bzero (char *s, size_t n)
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{
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__builtin_bzero (s, n);
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}
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#else
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typedef char *(*proto_t) (char *, int, size_t);
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char *builtin_memset (char *, int, size_t);
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IMPL (simple_memset, 0)
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IMPL (builtin_memset, 0)
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IMPL (memset, 1)
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char *
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builtin_memset (char *s, int c, size_t n)
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{
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return __builtin_memset (s, c, n);
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}
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#endif
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char *
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inhibit_loop_to_libcall
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simple_memset (char *s, int c, size_t n)
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{
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char *r = s, *end = s + n;
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while (r < end)
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*r++ = c;
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return s;
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}
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static void
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do_one_test (impl_t *impl, char *s, int c __attribute ((unused)), size_t n)
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{
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size_t i, iters = INNER_LOOP_ITERS;
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timing_t start, stop, cur;
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char tstbuf[n];
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#ifdef TEST_BZERO
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simple_bzero (tstbuf, n);
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CALL (impl, s, n);
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if (memcmp (s, tstbuf, n) != 0)
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#else
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char *res = CALL (impl, s, c, n);
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if (res != s
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|| simple_memset (tstbuf, c, n) != tstbuf
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|| memcmp (s, tstbuf, n) != 0)
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#endif
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{
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error (0, 0, "Wrong result in function %s", impl->name);
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ret = 1;
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return;
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}
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TIMING_NOW (start);
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for (i = 0; i < iters; ++i)
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{
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#ifdef TEST_BZERO
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CALL (impl, s, n);
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#else
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CALL (impl, s, c, n);
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#endif
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}
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TIMING_NOW (stop);
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TIMING_DIFF (cur, start, stop);
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TIMING_PRINT_MEAN ((double) cur, (double) iters);
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}
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static void
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do_test (size_t align, int c, size_t len)
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{
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align &= 7;
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if (align + len > page_size)
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return;
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printf ("Length %4zd, alignment %2zd, c %2d:", len, align, c);
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FOR_EACH_IMPL (impl, 0)
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do_one_test (impl, (char *) buf1 + align, c, len);
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putchar ('\n');
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}
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int
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test_main (void)
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{
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size_t i;
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int c = 0;
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test_init ();
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printf ("%24s", "");
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FOR_EACH_IMPL (impl, 0)
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printf ("\t%s", impl->name);
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putchar ('\n');
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#ifndef TEST_BZERO
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for (c = -65; c <= 130; c += 65)
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#endif
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{
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for (i = 0; i < 18; ++i)
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do_test (0, c, 1 << i);
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for (i = 1; i < 32; ++i)
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{
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do_test (i, c, i);
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if (i & (i - 1))
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do_test (0, c, i);
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}
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for (i = 32; i < 512; i+=32)
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{
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do_test (0, c, i);
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do_test (i, c, i);
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}
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do_test (1, c, 14);
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do_test (3, c, 1024);
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do_test (4, c, 64);
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do_test (2, c, 25);
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}
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return ret;
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}
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#include "../test-skeleton.c"
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