Re: [PATCH v2] Add math-inline benchmark

["Carlos O'Donell" <carlos at redhat dot com>]

On 07/20/2015 12:38 PM, Wilco Dijkstra wrote:
>> Siddhesh Poyarekar wrote:
>> > On Fri, Jul 17, 2015 at 09:49:42AM -0400, Carlos O'Donell wrote:
>>> > > Maybe we can place this in another C file e.g. bench-util.c and #include that
>>> > > and then call those functions?
>> > 
>> > Yes, that is fine.
> I've extracted the start function in bench-util.c, see updated version.
> 
> Wilco

One nit, OK to commit with that fixed.

See at the very end.

> 0001-Add-bench-math-inlines.txt
> 
> 
> ---
>  benchtests/Makefile             |   7 +-
>  benchtests/bench-math-inlines.c | 340 ++++++++++++++++++++++++++++++++++++++++
>  benchtests/bench-skeleton.c     |  18 +--
>  benchtests/bench-util.c         |  34 ++++
>  benchtests/bench-util.h         |  29 ++++
>  5 files changed, 412 insertions(+), 16 deletions(-)
>  create mode 100644 benchtests/bench-math-inlines.c
>  create mode 100644 benchtests/bench-util.c
>  create mode 100644 benchtests/bench-util.h
> 
> diff --git a/benchtests/Makefile b/benchtests/Makefile
> index 8e615e5..91970f8 100644
> --- a/benchtests/Makefile
> +++ b/benchtests/Makefile
> @@ -36,6 +36,7 @@ string-bench := bcopy bzero memccpy memchr memcmp memcpy memmem memmove \
>  		strncasecmp strncat strncmp strncpy strnlen strpbrk strrchr \
>  		strspn strstr strcpy_chk stpcpy_chk memrchr strsep strtok \
>  		strcoll
> +
>  string-bench-all := $(string-bench)
>  
>  # We have to generate locales
> @@ -50,7 +51,10 @@ stdlib-bench := strtod
>  
>  stdio-common-bench := sprintf
>  
> -benchset := $(string-bench-all) $(stdlib-bench) $(stdio-common-bench)
> +math-benchset := math-inlines
> +
> +benchset := $(string-bench-all) $(stdlib-bench) $(stdio-common-bench) \
> +	    $(math-benchset)

OK.

>  
>  CFLAGS-bench-ffs.c += -fno-builtin
>  CFLAGS-bench-ffsll.c += -fno-builtin
> @@ -58,6 +62,7 @@ CFLAGS-bench-ffsll.c += -fno-builtin
>  bench-malloc := malloc-thread
>  
>  $(addprefix $(objpfx)bench-,$(bench-math)): $(libm)
> +$(addprefix $(objpfx)bench-,$(math-benchset)): $(libm)
>  $(addprefix $(objpfx)bench-,$(bench-pthread)): $(shared-thread-library)
>  $(objpfx)bench-malloc-thread: $(shared-thread-library)
>  
> diff --git a/benchtests/bench-math-inlines.c b/benchtests/bench-math-inlines.c
> new file mode 100644
> index 0000000..da8a433
> --- /dev/null
> +++ b/benchtests/bench-math-inlines.c
> @@ -0,0 +1,340 @@
> +/* Measure math inline functions.

OK.

> +   Copyright (C) 2015 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 SIZE 1024
> +#define TEST_MAIN
> +#define TEST_NAME "math-inlines"
> +#define TEST_FUNCTION test_main ()
> +#include "bench-timing.h"
> +#include "json-lib.h"
> +#include "bench-util.h"
> +
> +#include <stdlib.h>
> +#include <math.h>
> +#include <stdint.h>
> +

OK.

> +
> +#define BOOLTEST(func)					  \
> +int							  \
> +func ## _t (volatile double *p, size_t n, size_t iters)   \
> +{							  \
> +  int i, j;						  \
> +  int res = 0;						  \
> +  for (j = 0; j < iters; j++)				  \
> +    for (i = 0; i < n; i++)				  \
> +      { double tmp = p[i] * 2.0;			  \
> +	if (func (tmp)) res += 5; }			  \
> +  return res;						  \
> +}
> +
> +#define VALUETEST(func)					  \
> +int							  \
> +func ## _t (volatile double *p, size_t n, size_t iters)	  \
> +{							  \
> +  int i, j;						  \
> +  int res = 0;						  \
> +  for (j = 0; j < iters; j++)				  \
> +    for (i = 0; i < n; i++)				  \
> +      { double tmp = p[i] * 2.0;			  \
> +	if (func (tmp)) res += 5; }			  \
> +  return res;						  \
> +}
> +
> +typedef union
> +{
> +  double value;
> +  uint64_t word;
> +} ieee_double_shape_type;
> +
> +#define EXTRACT_WORDS64(i,d)				  \
> +do {							  \
> +  ieee_double_shape_type gh_u;				  \
> +  gh_u.value = (d);					  \
> +  (i) = gh_u.word;					  \
> +} while (0)
> +
> +/* Explicit inlines similar to math_private.h versions.  */
> +
> +extern __always_inline int
> +__isnan_inl (double d)
> +{
> +  uint64_t di;
> +  EXTRACT_WORDS64 (di, d);
> +  return (di & 0x7fffffffffffffffull) > 0x7ff0000000000000ull;
> +}
> +
> +extern __always_inline int
> +__isnan_builtin (double d)
> +{
> +  return __builtin_isnan (d);
> +}
> +
> +extern __always_inline int
> +__isinf_inl (double x)
> +{
> +  uint64_t ix;
> +  EXTRACT_WORDS64 (ix,x);
> +  if ((ix << 1) != 0xffe0000000000000ull)
> +    return 0;
> +  return (int)(ix >> 32);
> +}
> +
> +extern __always_inline int
> +__isinf_ns (double d)
> +{
> +  uint64_t di;
> +  EXTRACT_WORDS64 (di, d);
> +  return (di & 0x7fffffffffffffffull) == 0x7ff0000000000000ull;
> +}
> +
> +extern __always_inline int
> +__isinf_ns_builtin (double d)
> +{
> +  return __builtin_isinf (d);
> +}
> +
> +extern __always_inline int
> +__isinf_builtin (double d)
> +{
> +  return __builtin_isinf_sign (d);
> +}
> +
> +
> +extern __always_inline int
> +__finite_inl (double d)
> +{
> +  uint64_t di;
> +  EXTRACT_WORDS64 (di, d);
> +  return (di & 0x7fffffffffffffffull) < 0x7ff0000000000000ull;
> +}
> +
> +extern __always_inline int
> +__isfinite_builtin (double d)
> +{
> +  return __builtin_isfinite (d);
> +}
> +
> +
> +/* Explicit inline similar to existing math.h implementation.  */
> +
> +#define __isnormal_inl(X) (__fpclassify (X) == FP_NORMAL)
> +#define __isnormal_inl2(X) (fpclassify (X) == FP_NORMAL)
> +
> +extern __always_inline int
> +__isnormal_builtin (double d)
> +{
> +  return __builtin_isnormal (d);
> +}
> +
> +/* Test fpclassify with use of only 2 of the 5 results.  */
> +
> +extern __always_inline int
> +__fpclassify_test1 (double d)
> +{
> +  int cl = fpclassify (d);
> +  return cl == FP_NAN || cl == FP_INFINITE;
> +}
> +
> +extern __always_inline int
> +__fpclassify_test2 (double d)
> +{
> +  return __builtin_isnan (d) || __builtin_isinf (d);
> +}
> +
> +double __attribute ((noinline))
> +kernel_standard (double x, double y, int z)
> +{
> +  return x * y + z;
> +}
> +
> +double __attribute ((noinline))
> +remainder2 (double x, double y)
> +{
> +  if (((__builtin_expect (y == 0.0, 0) && !__builtin_isnan (x))
> +	|| (__builtin_expect (__builtin_isinf (x), 0) && !__builtin_isnan (y))))
> +    return kernel_standard (x, y, 10);
> +
> +  return remainder (x, y);
> +}
> +
> +double __attribute ((noinline))
> +remainder1 (double x, double y)
> +{
> +  if (((__builtin_expect (y == 0.0, 0) && !__isnan_inl (x))
> +       || (__builtin_expect (__isinf_ns (x), 0) && !__isnan_inl (y))))
> +    return kernel_standard (x, y, 10);
> +
> +  return remainder (x, y);
> +}
> +
> +volatile double rem1 = 2.5;
> +
> +extern __always_inline int
> +remainder_test1 (double d)
> +{
> +  return remainder1 (d, rem1);
> +}
> +
> +extern __always_inline int
> +remainder_test2 (double d)
> +{
> +  return remainder2 (d, rem1);
> +}
> +
> +/* Create test functions for each possibility.  */
> +
> +BOOLTEST (__isnan)
> +BOOLTEST (__isnan_inl)
> +BOOLTEST (__isnan_builtin)
> +BOOLTEST (isnan)
> +
> +BOOLTEST (__isinf)
> +BOOLTEST (__isinf_inl)
> +BOOLTEST (__isinf_ns)
> +BOOLTEST (__isinf_ns_builtin)
> +BOOLTEST (__isinf_builtin)
> +BOOLTEST (isinf)
> +
> +BOOLTEST (__finite)
> +BOOLTEST (__finite_inl)
> +BOOLTEST (__isfinite_builtin)
> +BOOLTEST (isfinite)
> +
> +BOOLTEST (__isnormal_inl)
> +BOOLTEST (__isnormal_inl2)
> +BOOLTEST (__isnormal_builtin)
> +BOOLTEST (isnormal)
> +
> +BOOLTEST (__fpclassify_test1)
> +BOOLTEST (__fpclassify_test2)
> +VALUETEST (__fpclassify)
> +VALUETEST (fpclassify)
> +
> +BOOLTEST (remainder_test1)
> +BOOLTEST (remainder_test2)
> +
> +typedef int (*proto_t) (volatile double *p, size_t n, size_t iters);
> +
> +typedef struct
> +{
> +  const char *name;
> +  proto_t fn;
> +} impl_t;
> +
> +#define IMPL(name) { #name, name }
> +
> +impl_t test_list[] =
> +{
> +  IMPL (__isnan_t),
> +  IMPL (__isnan_inl_t),
> +  IMPL (__isnan_builtin_t),
> +  IMPL (isnan_t),
> +
> +  IMPL (__isinf_t),
> +  IMPL (__isinf_inl_t),
> +  IMPL (__isinf_ns_t),
> +  IMPL (__isinf_ns_builtin_t),
> +  IMPL (__isinf_builtin_t),
> +  IMPL (isinf_t),
> +
> +  IMPL (__finite_t),
> +  IMPL (__finite_inl_t),
> +  IMPL (__isfinite_builtin_t),
> +  IMPL (isfinite_t),
> +
> +  IMPL (__isnormal_inl_t),
> +  IMPL (__isnormal_inl2_t),
> +  IMPL (__isnormal_builtin_t),
> +  IMPL (isnormal_t),
> +
> +  IMPL (__fpclassify_test1_t),
> +  IMPL (__fpclassify_test2_t),
> +  IMPL (__fpclassify_t),
> +  IMPL (fpclassify_t),
> +
> +  IMPL (remainder_test1_t),
> +  IMPL (remainder_test2_t)
> +};
> +
> +static void
> +do_one_test (json_ctx_t *json_ctx, proto_t test_fn, volatile double *arr,
> +	     size_t len, const char *testname)
> +{
> +  size_t iters = 500;
> +  timing_t start, stop, cur;
> +
> +  json_attr_object_begin (json_ctx, testname);
> +
> +  TIMING_NOW (start);
> +  test_fn (arr, len, iters);
> +  TIMING_NOW (stop);
> +  TIMING_DIFF (cur, start, stop);
> +
> +  json_attr_double (json_ctx, "duration", cur);
> +  json_attr_double (json_ctx, "iterations", iters);
> +  json_attr_double (json_ctx, "mean", cur / iters);
> +  json_attr_object_end (json_ctx);
> +}
> +
> +static volatile double arr1[SIZE];
> +static volatile double arr2[SIZE];
> +
> +int
> +test_main (void)
> +{
> +  json_ctx_t json_ctx;
> +  size_t i;
> +
> +  bench_start ();
> +
> +  json_init (&json_ctx, 2, stdout);
> +  json_attr_object_begin (&json_ctx, "math-inlines");
> +
> +  /* Create 2 test arrays, one with 10% zeroes, 10% negative values,
> +     79% positive values and 1% infinity/NaN.  The other contains
> +     50% inf, 50% NaN.  */
> +
> +  for (i = 0; i < SIZE; i++)
> +    {
> +      int x = rand () & 255;
> +      arr1[i] = (x < 25) ? 0.0 : ((x < 50) ? -1 : 100);
> +      if (x == 255) arr1[i] = __builtin_inf ();
> +      if (x == 254) arr1[i] = __builtin_nan ("0");
> +      arr2[i] = (x < 128) ? __builtin_inf () : __builtin_nan ("0");
> +    }
> +
> +  for (i = 0; i < sizeof (test_list) / sizeof (test_list[0]); i++)
> +    {
> +      json_attr_object_begin (&json_ctx, test_list[i].name);
> +      do_one_test (&json_ctx, test_list[i].fn, arr2, SIZE, "inf/nan");
> +      json_attr_object_end (&json_ctx);
> +    }
> +
> +  for (i = 0; i < sizeof (test_list) / sizeof (test_list[0]); i++)
> +    {
> +      json_attr_object_begin (&json_ctx, test_list[i].name);
> +      do_one_test (&json_ctx, test_list[i].fn, arr1, SIZE, "normal");
> +      json_attr_object_end (&json_ctx);
> +    }
> +
> +  json_attr_object_end (&json_ctx);
> +  return 0;
> +}
> +
> +#include "bench-util.c"
> +#include "../test-skeleton.c"
> diff --git a/benchtests/bench-skeleton.c b/benchtests/bench-skeleton.c
> index e357f0c..bc820df 100644
> --- a/benchtests/bench-skeleton.c
> +++ b/benchtests/bench-skeleton.c
> @@ -24,21 +24,9 @@
>  #include <inttypes.h>
>  #include "bench-timing.h"
>  #include "json-lib.h"
> +#include "bench-util.h"
>  
> -volatile unsigned int dontoptimize = 0;
> -
> -void
> -startup (void)
> -{
> -  /* This loop should cause CPU to switch to maximal freqency.
> -     This makes subsequent measurement more accurate.  We need a side effect
> -     to prevent the loop being deleted by compiler.
> -     This should be enough to cause CPU to speed up and it is simpler than
> -     running loop for constant time. This is used when user does not have root
> -     access to set a constant freqency.  */
> -  for (int k = 0; k < 10000000; k++)
> -    dontoptimize += 23 * dontoptimize + 2;
> -}
> +#include "bench-util.c"

OK.

>  
>  #define TIMESPEC_AFTER(a, b) \
>    (((a).tv_sec == (b).tv_sec) ?						      \
> @@ -56,7 +44,7 @@ main (int argc, char **argv)
>    if (argc == 2 && !strcmp (argv[1], "-d"))
>      detailed = true;
>  
> -  startup();
> +  bench_start ();

OK.

>  
>    memset (&runtime, 0, sizeof (runtime));
>  
> diff --git a/benchtests/bench-util.c b/benchtests/bench-util.c
> new file mode 100644
> index 0000000..c4149ae
> --- /dev/null
> +++ b/benchtests/bench-util.c
> @@ -0,0 +1,34 @@
> +/* Benchmark utility functions.
> +   Copyright (C) 2015 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/>.  */
> +
> +
> +static volatile unsigned int dontoptimize = 0;
> +
> +void
> +bench_start (void)
> +{
> +  /* This loop should cause CPU to switch to maximal freqency.
> +     This makes subsequent measurement more accurate.  We need a side effect
> +     to prevent the loop being deleted by compiler.
> +     This should be enough to cause CPU to speed up and it is simpler than
> +     running loop for constant time.  This is used when user does not have root
> +     access to set a constant freqency.  */
> +
> +  for (int k = 0; k < START_ITER; k++)
> +    dontoptimize += 23 * dontoptimize + 2;
> +}

OK.

> diff --git a/benchtests/bench-util.h b/benchtests/bench-util.h
> new file mode 100644
> index 0000000..b30b085
> --- /dev/null
> +++ b/benchtests/bench-util.h
> @@ -0,0 +1,29 @@
> +/* Benchmark utility functions.
> +   Copyright (C) 2015 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/>.  */
> +
> +
> +#ifndef START_ITER
> +# define START_ITER (100000000)
> +#endif
> +
> +/* bench_start reduces the random variations due to frequency scaling by
> +   executing a small loop with many memory accesses.  START_ITER controls
> +   the number of iterations.  */
> +
> +void
> +bench_start (void);

One line please, only function definitions are split on two lines to make
it easier to find e.g. grep '^bench_start' *. Per GNU Coding Standard.

OK with this change.

> -- 1.9.1

Cheers,
Carlos.