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[PATCH] Support separate benchmark outputs


Hi,

Currently the benchmark supports simple computation of mean time,
throughput, etc of functions over a varied set of inputs.  The string
benchmarks measure multiple versions of the same function and do a
comparison for different alignments and sizes and this does not fit
into the generic output format.  It would be undesirable to try and
fit them into the generic format either since their current output
format is useful and may not be easily reproducible with the benchmark
format.

Hence the concept of benchmark sets, i.e. a set of benchmark
measurements in a single program that have their own output.
Essentially the only differentiator for this idea is that it prints
its output into a separate file of its own and not in bench.out.  I've
added a comment in benchtests/Makefile to explain how one can add a
benchset.

In addition to support for benchsets, this patch also adds memcpy and
memcpy-ifunc as proof of concept.  These are just test-memcpy and
test-memcpy-ifunc copied over for now.  Once this patch is in, I will
post patches to similarly copy over the rest of the string performance
test functions.  After that, I will remove the performance measurement
bits from the string/test-* and the correctness tests from
benchtest/bench-*.

Siddhesh

	* benchtests/Makefile: Add comment describing benchsets.
	Ensure that no targets run in parallel.
	(benchset): New set of benchmark sets.
	(bench): Depend on bench-func and bench-set.
	(bench-set): New target.
	(bench-func): Renamed from bench.
	* benchtests/bench-memcpy-ifunc.c: New file.
	* benchtests/bench-memcpy.c: New file.
	* benchtests/bench-string.h: New file.

diff --git a/benchtests/Makefile b/benchtests/Makefile
index 120c47a..a453e06 100644
--- a/benchtests/Makefile
+++ b/benchtests/Makefile
@@ -44,9 +44,31 @@
 #   being a comma separated list of arguments to be passed into the function.
 #   See pow-inputs for an example.
 
+# Benchmark Sets:
+# --------------
+#
+# In addition to standard benchmarking of functions, one may also generate
+# custom outputs for a set of functions.  This is currentlyy used by string
+# function benchmarks where the aim is to compare performance between
+# implementations at various alignments and for various sizes.
+#
+# To add a benchset for `foo':
+#
+# - Add `foo' to the benchset variable.
+# - Write your bench-foo.c that prints out the measurements to stdout.
+# - On execution, a bench-foo.out is created in $(objpfx) with the contents of
+#   stdout.
+
 subdir := benchtests
+
 bench := exp pow rint sin atan slowexp slowpow slowsin slowatan
 
+string-bench := memcpy
+string-bench-ifunc := $(addsuffix -ifunc, $(string-bench))
+string-bench-all := $(string-bench) $(string-bench-ifunc)
+
+benchset := $(string-bench-all)
+
 # exp function fast path
 exp-ITER = 5e8
 exp-ARGLIST = double
@@ -109,6 +131,8 @@ LDFLAGS-bench-slowatan = -lm
 # Rules to build and execute the benchmarks.  Do not put any benchmark
 # parameters beyond this point.
 
+.NOTPARALLEL:
+
 ifdef USE_CLOCK_GETTIME
 bench-cflags := -DUSE_CLOCK_GETTIME
 endif
@@ -117,10 +141,11 @@ include ../Makeconfig
 include ../Rules
 
 binaries-bench := $(addprefix $(objpfx)bench-,$(bench))
+binaries-benchset := $(addprefix $(objpfx)bench-,$(benchset))
 
 # This makes sure CPPFLAGS-nonlib and CFLAGS-nonlib are passed
 # for all these modules.
-cpp-srcs-left := $(binaries-bench:=.c)
+cpp-srcs-left := $(binaries-benchset:=.c) $(binaries-bench:=.c)
 lib := nonlib
 include $(patsubst %,$(..)cppflags-iterator.mk,$(cpp-srcs-left))
 
@@ -132,8 +157,17 @@ run-bench = $(test-wrapper-env) \
 
 bench-clean:
 	rm -f $(binaries-bench) $(addsuffix .o,$(binaries-bench))
+	rm -f $(binaries-benchset) $(addsuffix .o,$(binaries-benchset))
+
+bench: bench-set bench-func
+
+bench-set: $(binaries-benchset)
+	for run in $^; do \
+	  echo "Running $${run}"; \
+	  $(run-bench) > $${run}.out; \
+	done
 
-bench: $(binaries-bench)
+bench-func: $(binaries-bench)
 	{ for run in $^; do \
 	  echo "Running $${run}" >&2; \
 	  $(run-bench); \
@@ -143,7 +177,7 @@ bench: $(binaries-bench)
 	fi; \
 	mv -f $(objpfx)bench.out-tmp $(objpfx)bench.out
 
-$(binaries-bench): %: %.o \
+$(binaries-bench) $(binaries-benchset): %: %.o \
   $(sort $(filter $(common-objpfx)lib%,$(link-libc))) \
   $(addprefix $(csu-objpfx),start.o) $(+preinit) $(+postinit)
 	$(+link)
diff --git a/benchtests/bench-memcpy-ifunc.c b/benchtests/bench-memcpy-ifunc.c
new file mode 100644
index 0000000..1164996
--- /dev/null
+++ b/benchtests/bench-memcpy-ifunc.c
@@ -0,0 +1,20 @@
+/* Test and measure IFUNC implementations of memcpy function.
+   Copyright (C) 2012-2013 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#define TEST_IFUNC 1
+#include "bench-memcpy.c"
diff --git a/benchtests/bench-memcpy.c b/benchtests/bench-memcpy.c
new file mode 100644
index 0000000..6997def
--- /dev/null
+++ b/benchtests/bench-memcpy.c
@@ -0,0 +1,277 @@
+/* Test and measure memcpy functions.
+   Copyright (C) 1999-2013 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Written by Jakub Jelinek <jakub@redhat.com>, 1999.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef MEMCPY_RESULT
+# define MEMCPY_RESULT(dst, len) dst
+# define MIN_PAGE_SIZE 131072
+# define TEST_MAIN
+# define TEST_NAME "memcpy"
+# include "bench-string.h"
+
+char *simple_memcpy (char *, const char *, size_t);
+char *builtin_memcpy (char *, const char *, size_t);
+
+IMPL (simple_memcpy, 0)
+IMPL (builtin_memcpy, 0)
+IMPL (memcpy, 1)
+
+char *
+simple_memcpy (char *dst, const char *src, size_t n)
+{
+  char *ret = dst;
+  while (n--)
+    *dst++ = *src++;
+  return ret;
+}
+
+char *
+builtin_memcpy (char *dst, const char *src, size_t n)
+{
+  return __builtin_memcpy (dst, src, n);
+}
+#endif
+
+typedef char *(*proto_t) (char *, const char *, size_t);
+
+static void
+do_one_test (impl_t *impl, char *dst, const char *src,
+	     size_t len)
+{
+  if (CALL (impl, dst, src, len) != MEMCPY_RESULT (dst, len))
+    {
+      error (0, 0, "Wrong result in function %s %p %p", impl->name,
+	     CALL (impl, dst, src, len), MEMCPY_RESULT (dst, len));
+      ret = 1;
+      return;
+    }
+
+  if (memcmp (dst, src, len) != 0)
+    {
+      error (0, 0, "Wrong result in function %s dst \"%s\" src \"%s\"",
+	     impl->name, dst, src);
+      ret = 1;
+      return;
+    }
+
+  if (HP_TIMING_AVAIL)
+    {
+      hp_timing_t start __attribute ((unused));
+      hp_timing_t stop __attribute ((unused));
+      hp_timing_t best_time = ~ (hp_timing_t) 0;
+      size_t i;
+
+      for (i = 0; i < 32; ++i)
+	{
+	  HP_TIMING_NOW (start);
+	  CALL (impl, dst, src, len);
+	  HP_TIMING_NOW (stop);
+	  HP_TIMING_BEST (best_time, start, stop);
+	}
+
+      printf ("\t%zd", (size_t) best_time);
+    }
+}
+
+static void
+do_test (size_t align1, size_t align2, size_t len)
+{
+  size_t i, j;
+  char *s1, *s2;
+
+  align1 &= 63;
+  if (align1 + len >= page_size)
+    return;
+
+  align2 &= 63;
+  if (align2 + len >= page_size)
+    return;
+
+  s1 = (char *) (buf1 + align1);
+  s2 = (char *) (buf2 + align2);
+
+  for (i = 0, j = 1; i < len; i++, j += 23)
+    s1[i] = j;
+
+  if (HP_TIMING_AVAIL)
+    printf ("Length %4zd, alignment %2zd/%2zd:", len, align1, align2);
+
+  FOR_EACH_IMPL (impl, 0)
+    do_one_test (impl, s2, s1, len);
+
+  if (HP_TIMING_AVAIL)
+    putchar ('\n');
+}
+
+static void
+do_random_tests (void)
+{
+  size_t i, j, n, align1, align2, len, size1, size2, size;
+  int c;
+  unsigned char *p1, *p2;
+  unsigned char *res;
+
+  for (n = 0; n < ITERATIONS; n++)
+    {
+      if (n == 0)
+	{
+	  len = getpagesize ();
+	  size = len + 512;
+	  size1 = size;
+	  size2 = size;
+	  align1 = 512;
+	  align2 = 512;
+	}
+      else
+	{
+	  if ((random () & 255) == 0)
+	    size = 65536;
+	  else
+	    size = 768;
+	  if (size > page_size)
+	    size = page_size;
+	  size1 = size;
+	  size2 = size;
+	  i = random ();
+	  if (i & 3)
+	    size -= 256;
+	  if (i & 1)
+	    size1 -= 256;
+	  if (i & 2)
+	    size2 -= 256;
+	  if (i & 4)
+	    {
+	      len = random () % size;
+	      align1 = size1 - len - (random () & 31);
+	      align2 = size2 - len - (random () & 31);
+	      if (align1 > size1)
+		align1 = 0;
+	      if (align2 > size2)
+		align2 = 0;
+	    }
+	  else
+	    {
+	      align1 = random () & 63;
+	      align2 = random () & 63;
+	      len = random () % size;
+	      if (align1 + len > size1)
+		align1 = size1 - len;
+	      if (align2 + len > size2)
+		align2 = size2 - len;
+	    }
+	}
+      p1 = buf1 + page_size - size1;
+      p2 = buf2 + page_size - size2;
+      c = random () & 255;
+      j = align1 + len + 256;
+      if (j > size1)
+	j = size1;
+      for (i = 0; i < j; ++i)
+	p1[i] = random () & 255;
+
+      FOR_EACH_IMPL (impl, 1)
+	{
+	  j = align2 + len + 256;
+	  if (j > size2)
+	    j = size2;
+	  memset (p2, c, j);
+	  res = (unsigned char *) CALL (impl,
+					(char *) (p2 + align2),
+					(char *) (p1 + align1), len);
+	  if (res != MEMCPY_RESULT (p2 + align2, len))
+	    {
+	      error (0, 0, "Iteration %zd - wrong result in function %s (%zd, %zd, %zd) %p != %p",
+		     n, impl->name, align1, align2, len, res,
+		     MEMCPY_RESULT (p2 + align2, len));
+	      ret = 1;
+	    }
+	  for (i = 0; i < align2; ++i)
+	    {
+	      if (p2[i] != c)
+		{
+		  error (0, 0, "Iteration %zd - garbage before, %s (%zd, %zd, %zd)",
+			 n, impl->name, align1, align2, len);
+		  ret = 1;
+		  break;
+		}
+	    }
+	  for (i = align2 + len; i < j; ++i)
+	    {
+	      if (p2[i] != c)
+		{
+		  error (0, 0, "Iteration %zd - garbage after, %s (%zd, %zd, %zd)",
+			 n, impl->name, align1, align2, len);
+		  ret = 1;
+		  break;
+		}
+	    }
+	  if (memcmp (p1 + align1, p2 + align2, len))
+	    {
+	      error (0, 0, "Iteration %zd - different strings, %s (%zd, %zd, %zd)",
+		     n, impl->name, align1, align2, len);
+	      ret = 1;
+	    }
+	}
+    }
+}
+
+int
+test_main (void)
+{
+  size_t i;
+
+  test_init ();
+
+  printf ("%23s", "");
+  FOR_EACH_IMPL (impl, 0)
+    printf ("\t%s", impl->name);
+  putchar ('\n');
+
+  for (i = 0; i < 18; ++i)
+    {
+      do_test (0, 0, 1 << i);
+      do_test (i, 0, 1 << i);
+      do_test (0, i, 1 << i);
+      do_test (i, i, 1 << i);
+    }
+
+  for (i = 0; i < 32; ++i)
+    {
+      do_test (0, 0, i);
+      do_test (i, 0, i);
+      do_test (0, i, i);
+      do_test (i, i, i);
+    }
+
+  for (i = 3; i < 32; ++i)
+    {
+      if ((i & (i - 1)) == 0)
+	continue;
+      do_test (0, 0, 16 * i);
+      do_test (i, 0, 16 * i);
+      do_test (0, i, 16 * i);
+      do_test (i, i, 16 * i);
+    }
+
+  do_test (0, 0, getpagesize ());
+
+  do_random_tests ();
+  return ret;
+}
+
+#include "../test-skeleton.c"
diff --git a/benchtests/bench-string.h b/benchtests/bench-string.h
new file mode 100644
index 0000000..47659d0
--- /dev/null
+++ b/benchtests/bench-string.h
@@ -0,0 +1,213 @@
+/* Test and measure string and memory functions.
+   Copyright (C) 1999-2013 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Written by Jakub Jelinek <jakub@redhat.com>, 1999.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sys/cdefs.h>
+
+typedef struct
+{
+  const char *name;
+  void (*fn) (void);
+  long test;
+} impl_t;
+extern impl_t __start_impls[], __stop_impls[];
+
+#define IMPL(name, test) \
+  impl_t tst_ ## name							\
+  __attribute__ ((section ("impls"), aligned (sizeof (void *))))	\
+       = { __STRING (name), (void (*) (void))name, test };
+
+#ifdef TEST_MAIN
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#undef __USE_STRING_INLINES
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/param.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <error.h>
+#include <errno.h>
+#include <time.h>
+#include <ifunc-impl-list.h>
+#define GL(x) _##x
+#define GLRO(x) _##x
+#include <hp-timing.h>
+
+
+# define TEST_FUNCTION test_main ()
+# define TIMEOUT (4 * 60)
+# define OPT_ITERATIONS 10000
+# define OPT_RANDOM 10001
+# define OPT_SEED 10002
+
+unsigned char *buf1, *buf2;
+int ret, do_srandom;
+unsigned int seed;
+size_t page_size;
+
+hp_timing_t _dl_hp_timing_overhead;
+
+# ifndef ITERATIONS
+size_t iterations = 100000;
+#  define ITERATIONS_OPTIONS \
+  { "iterations", required_argument, NULL, OPT_ITERATIONS },
+#  define ITERATIONS_PROCESS \
+  case OPT_ITERATIONS:				\
+    iterations = strtoul (optarg, NULL, 0);	\
+    break;
+#  define ITERATIONS iterations
+# else
+#  define ITERATIONS_OPTIONS
+#  define ITERATIONS_PROCESS
+# endif
+
+# define CMDLINE_OPTIONS ITERATIONS_OPTIONS \
+  { "random", no_argument, NULL, OPT_RANDOM },	\
+  { "seed", required_argument, NULL, OPT_SEED },
+# define CMDLINE_PROCESS ITERATIONS_PROCESS \
+  case OPT_RANDOM:							\
+    {									\
+      int fdr = open ("/dev/urandom", O_RDONLY);			\
+									\
+      if (fdr < 0 || read (fdr, &seed, sizeof(seed)) != sizeof (seed))	\
+	seed = time (NULL);						\
+      if (fdr >= 0)							\
+	close (fdr);							\
+      do_srandom = 1;							\
+      break;								\
+    }									\
+									\
+  case OPT_SEED:							\
+    seed = strtoul (optarg, NULL, 0);					\
+    do_srandom = 1;							\
+    break;
+
+#define CALL(impl, ...)	\
+  (* (proto_t) (impl)->fn) (__VA_ARGS__)
+
+#if defined TEST_IFUNC && defined TEST_NAME
+/* Increase size of FUNC_LIST if assert is triggered at run-time.  */
+static struct libc_ifunc_impl func_list[32];
+static int func_count;
+static int impl_count = -1;
+static impl_t *impl_array;
+
+# define FOR_EACH_IMPL(impl, notall) \
+  impl_t *impl;								\
+  int count;								\
+  if (impl_count == -1)							\
+    {									\
+      impl_count = 0;							\
+      if (func_count != 0)						\
+	{								\
+	  int f;							\
+	  impl_t *skip = NULL, *a;					\
+	  for (impl = __start_impls; impl < __stop_impls; ++impl)	\
+	    if (strcmp (impl->name, TEST_NAME) == 0)			\
+	      skip = impl;						\
+	    else							\
+	      impl_count++;						\
+	  a = impl_array = malloc ((impl_count + func_count) *		\
+				   sizeof (impl_t));			\
+	  for (impl = __start_impls; impl < __stop_impls; ++impl)	\
+	    if (impl != skip)						\
+	      *a++ = *impl;						\
+	  for (f = 0; f < func_count; f++)				\
+	    if (func_list[f].usable)					\
+	      {								\
+		a->name = func_list[f].name;				\
+		a->fn = func_list[f].fn;				\
+		a->test = 1;						\
+		a++;							\
+	      }								\
+	  impl_count = a - impl_array;					\
+	}								\
+      else								\
+        {								\
+	  impl_count = __stop_impls - __start_impls;			\
+	  impl_array = __start_impls;					\
+        }								\
+    }									\
+  impl = impl_array;							\
+  for (count = 0; count < impl_count; ++count, ++impl)			\
+    if (!notall || impl->test)
+#else
+# define FOR_EACH_IMPL(impl, notall) \
+  for (impl_t *impl = __start_impls; impl < __stop_impls; ++impl)	\
+    if (!notall || impl->test)
+#endif
+
+#define HP_TIMING_BEST(best_time, start, end)	\
+  do									\
+    {									\
+      hp_timing_t tmptime;						\
+      HP_TIMING_DIFF (tmptime, start + _dl_hp_timing_overhead, end);	\
+      if (best_time > tmptime)						\
+	best_time = tmptime;						\
+    }									\
+  while (0)
+
+#ifndef BUF1PAGES
+# define BUF1PAGES 1
+#endif
+
+static void
+test_init (void)
+{
+#if defined TEST_IFUNC && defined TEST_NAME
+  func_count = __libc_ifunc_impl_list (TEST_NAME, func_list,
+				       (sizeof func_list
+					/ sizeof func_list[0]));
+#endif
+
+  page_size = 2 * getpagesize ();
+#ifdef MIN_PAGE_SIZE
+  if (page_size < MIN_PAGE_SIZE)
+    page_size = MIN_PAGE_SIZE;
+#endif
+  buf1 = mmap (0, (BUF1PAGES + 1) * page_size, PROT_READ | PROT_WRITE,
+	       MAP_PRIVATE | MAP_ANON, -1, 0);
+  if (buf1 == MAP_FAILED)
+    error (EXIT_FAILURE, errno, "mmap failed");
+  if (mprotect (buf1 + BUF1PAGES * page_size, page_size, PROT_NONE))
+    error (EXIT_FAILURE, errno, "mprotect failed");
+  buf2 = mmap (0, 2 * page_size, PROT_READ | PROT_WRITE,
+	       MAP_PRIVATE | MAP_ANON, -1, 0);
+  if (buf2 == MAP_FAILED)
+    error (EXIT_FAILURE, errno, "mmap failed");
+  if (mprotect (buf2 + page_size, page_size, PROT_NONE))
+    error (EXIT_FAILURE, errno, "mprotect failed");
+  HP_TIMING_DIFF_INIT ();
+  if (do_srandom)
+    {
+      printf ("Setting seed to 0x%x\n", seed);
+      srandom (seed);
+    }
+
+  memset (buf1, 0xa5, BUF1PAGES * page_size);
+  memset (buf2, 0x5a, page_size);
+}
+
+#endif


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