diff mbox

[v3] Add math-inline benchmark

Message ID 000001d0da84$c84110f0$58c332d0$@com
State New
Headers show

Commit Message

Wilco Aug. 19, 2015, 1:41 p.m. UTC
Ping (correct version of patch attached)

> Wilco Dijkstra wrote:
> Add a benchmark for isinf/isnan/isnormal/isfinite/fpclassify. The test uses 2 arrays with 1024
> doubles, one with 99% finite FP numbers (10% zeroes, 10% negative) and 1% inf/NaN, the other
> with 50% inf, and 50% Nan.
> 
> This version removes various tests that caused confusion and only leaves the existing GLIBC
> definitions and inlines for comparison with the GCC builtins. I changed the tests to not
> inline inside the loop and use a branch on the boolean result. The 64-bit immediates used by
> the GLIBC inlines seem very expensive on some microarchitectures, so this shows even more
> clearly that using the built-ins results in a significant performance gain (see x64 results
> below).
> 
> 
> ChangeLog:
> 2015-07-23  Wilco Dijkstra  <wdijkstr@arm.com>
> 
> 	* benchtests/Makefile: Add bench-math-inlines, link with libm.
> 	* benchtests/bench-math-inlines.c: New benchmark.
> 	* benchtests/bench-util.h: New file.
> 	* benchtests/bench-util.c: New file.
> 	* benchtests/bench-skeleton.c: Add include of bench-util.c/h.
> 
> 
>   "__isnan_t": {
>     "normal": {
>      "duration": 5.32475e+06,
>      "iterations": 500,
>      "mean": 10649
>     }
>    },
>    "__isnan_inl_t": {
>     "normal": {
>      "duration": 2.74296e+06,
>      "iterations": 500,
>      "mean": 5485
>     }
>    },
>    "__isnan_builtin_t": {
>     "normal": {
>      "duration": 2.35589e+06,
>      "iterations": 500,
>      "mean": 4711
>     }
>    },
>    "isnan_t": {
>     "normal": {
>      "duration": 2.25889e+06,
>      "iterations": 500,
>      "mean": 4517
>     }
>    },
>    "__isinf_t": {
>     "normal": {
>      "duration": 5.7671e+06,
>      "iterations": 500,
>      "mean": 11534
>     }
>    },
>    "__isinf_ns_t": {
>     "normal": {
>      "duration": 2.70963e+06,
>      "iterations": 500,
>      "mean": 5419
>     }
>    },
>    "__isinf_ns_builtin_t": {
>     "normal": {
>      "duration": 2.70841e+06,
>      "iterations": 500,
>      "mean": 5416
>     }
>    },
>    "__isinf_builtin_t": {
>     "normal": {
>      "duration": 2.26255e+06,
>      "iterations": 500,
>      "mean": 4525
>     }
>    },
>    "isinf_t": {
>     "normal": {
>      "duration": 2.26428e+06,
>      "iterations": 500,
>      "mean": 4528
>     }
>    },
>    "__finite_t": {
>     "normal": {
>      "duration": 5.82567e+06,
>      "iterations": 500,
>      "mean": 11651
>     }
>    },
>    "__finite_inl_t": {
>     "normal": {
>      "duration": 3.2019e+06,
>      "iterations": 500,
>      "mean": 6403
>     }
>    },
>    "__isfinite_builtin_t": {
>     "normal": {
>      "duration": 3.17892e+06,
>      "iterations": 500,
>      "mean": 6357
>     }
>    },
>    "isfinite_t": {
>     "normal": {
>      "duration": 2.75324e+06,
>      "iterations": 500,
>      "mean": 5506
>     }
>    },
>    "__isnormal_inl_t": {
>     "normal": {
>      "duration": 8.65908e+06,
>      "iterations": 500,
>      "mean": 17318
>    }
>    },
>    "__isnormal_builtin_t": {
>     "normal": {
>      "duration": 3.68589e+06,
>      "iterations": 500,
>      "mean": 7371
>     }
>    },
>    "isnormal_t": {
>     "normal": {
>      "duration": 3.76085e+06,
>      "iterations": 500,
>      "mean": 7521
>     }
>    },
>    "__fpclassify_t": {
>     "normal": {
>      "duration": 6.63574e+06,
>      "iterations": 500,
>      "mean": 13271
>     }
>    },
>    "__fpclassify_builtin_t": {
>     "normal": {
>      "duration": 4.48757e+06,
>      "iterations": 500,
>      "mean": 8975
>     }
>    },
>    "fpclassify_t": {
>     "normal": {
>      "duration": 4.48033e+06,
>      "iterations": 500,
>      "mean": 8960
>     }
>    },
>    "remainder_test1_t": {
>     "normal": {
>      "duration": 2.10051e+07,
>      "iterations": 500,
>      "mean": 42010
>     }
>    },
>    "remainder_test2_t": {
>     "normal": {
>      "duration": 1.9933e+07,
>      "iterations": 500,
>      "mean": 39865
>     }
>    }
>   }
---
 benchtests/Makefile             |   7 +-
 benchtests/bench-math-inlines.c | 284 ++++++++++++++++++++++++++++++++++++++++
 benchtests/bench-skeleton.c     |  18 +--
 benchtests/bench-util.c         |  34 +++++
 benchtests/bench-util.h         |  28 ++++
 5 files changed, 355 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

Comments

Siddhesh Poyarekar Sept. 16, 2015, 7:05 a.m. UTC | #1
Sorry, I assumed someone else (Carlos?) was reviewing this and then
forgot about it.  I've put review comments inline.  The major concern I
have is that you're duplicating contents of math_private.h to compare
it against the gcc builtins, which is fine as a first hack if you want
to avoid changing actual code for the tests, but may not be a good idea
in the long term.  That is, there is a risk that the inlines may be
modified but this test doesn't realize that.

I don't mind this going in as a first revision (with other changes
recommended below) provided you're willing to remedy this situation in
the next iteration so that there is at least a failure in running the
benchtest if the definitions of the inlines change in any way.

Siddhesh


On Wed, 2015-08-19 at 14:41 +0100, Wilco Dijkstra wrote:
> 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
> +

Unnecessary hunk.

>  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)
>  
>  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..1251935
> --- /dev/null
> +++ b/benchtests/bench-math-inlines.c
> @@ -0,0 +1,284 @@
> +/* Measure math inline 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/>.  */
> +
> +#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>
> +
> +#define BOOLTEST(func)					  \
> +int __attribute__((noinline))				  \

Make this function and others below static.

> +func ## _f (double d, int i)				  \
> +{							  \
> +  if (func (d))						  \
> +    return (int)d + i;					  \

Space after (int).

> +  else							  \
> +    return 5;						  \
> +}							  \
> +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++)				  \
> +      if (func ## _f (p[i] * 2.0, i))			  \

Avoid implicit boolean coercion.

> +	res += 5;					  \
> +  return res;						  \
> +}
> +
> +#define VALUETEST(func)					  \
> +int __attribute__((noinline))				  \
> +func ## _f (double d)					  \
> +{							  \
> +  return func (d);					  \
> +}							  \
> +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++)				  \
> +      res += func ## _f (p[i] * 2.0);			  \
> +  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)
> +
> +/* Inlines similar to existing math_private.h versions.  */

If seems a bit ugly to duplicate code from sysdeps/ieee754/dbl
-64/wordsize-64/math_private.h to test them.  Can you look at another
way to massage math_private.h so that you can do something as simple as
include the file and rewrite the function names using macros?  If it's
too hard or you want to do it in a second pass then please enhance the
comment to reflect that.

> +
> +extern __always_inline int

static __always_inline for this and everything else below.

> +__isnan_inl (double d)
> +{
> +  uint64_t di;
> +  EXTRACT_WORDS64 (di, d);
> +  return (di & 0x7fffffffffffffffull) > 0x7ff0000000000000ull;
> +}
> +
> +extern __always_inline int
> +__isinf_ns (double d)
> +{
> +  uint64_t di;
> +  EXTRACT_WORDS64 (di, d);
> +  return (di & 0x7fffffffffffffffull) == 0x7ff0000000000000ull;
> +}
> +extern __always_inline int
> +__finite_inl (double d)
> +{
> +  uint64_t di;
> +  EXTRACT_WORDS64 (di, d);
> +  return (di & 0x7fffffffffffffffull) < 0x7ff0000000000000ull;
> +}
> +
> +#define __isnormal_inl(X) (__fpclassify (X) == FP_NORMAL)
> +
> +/* Inlines for the builtin functions.  */
> +
> +#define __isnan_builtin(X) __builtin_isnan (X)
> +#define __isinf_ns_builtin(X) __builtin_isinf (X)
> +#define __isinf_builtin(X) __builtin_isinf_sign (X)
> +#define __isfinite_builtin(X) __builtin_isfinite (X)
> +#define __isnormal_builtin(X) __builtin_isnormal (X)
> +#define __fpclassify_builtin(X) __builtin_fpclassify (FP_NAN,
> FP_INFINITE,  \
> +				  FP_NORMAL, FP_SUBNORMAL, FP_ZERO,
> (X))
> +
> +double __attribute ((noinline))
> +kernel_standard (double x, double y, int z)
> +{
> +  return x * y + z;
> +}
> +
> +volatile double rem1 = 2.5;
> +
> +extern __always_inline double
> +remainder_test1 (double x)
> +{
> +  double y = rem1;
> +  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);
> +}
> +
> +extern __always_inline double
> +remainder_test2 (double x)
> +{
> +  double y = rem1;
> +  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);
> +}
> +
> +/* Create test functions for each possibility.  */
> +
> +BOOLTEST (__isnan)
> +BOOLTEST (__isnan_inl)
> +BOOLTEST (__isnan_builtin)
> +BOOLTEST (isnan)
> +
> +BOOLTEST (__isinf)
> +BOOLTEST (__isinf_builtin)
> +BOOLTEST (__isinf_ns)
> +BOOLTEST (__isinf_ns_builtin)
> +BOOLTEST (isinf)
> +
> +BOOLTEST (__finite)
> +BOOLTEST (__finite_inl)
> +BOOLTEST (__isfinite_builtin)
> +BOOLTEST (isfinite)
> +
> +BOOLTEST (__isnormal_inl)
> +BOOLTEST (__isnormal_builtin)
> +BOOLTEST (isnormal)
> +
> +VALUETEST (__fpclassify)
> +VALUETEST (__fpclassify_builtin)
> +VALUETEST (fpclassify)
> +
> +VALUETEST (remainder_test1)
> +VALUETEST (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 ## _t }
> +
> +impl_t test_list[] =

static impl_t test_list.

> +{
> +  IMPL (__isnan),
> +  IMPL (__isnan_inl),
> +  IMPL (__isnan_builtin),
> +  IMPL (isnan),
> +
> +  IMPL (__isinf),
> +  IMPL (__isinf_ns),
> +  IMPL (__isinf_ns_builtin),
> +  IMPL (__isinf_builtin),
> +  IMPL (isinf),
> +
> +  IMPL (__finite),
> +  IMPL (__finite_inl),
> +  IMPL (__isfinite_builtin),
> +  IMPL (isfinite),
> +
> +  IMPL (__isnormal_inl),
> +  IMPL (__isnormal_builtin),
> +  IMPL (isnormal),
> +
> +  IMPL (__fpclassify),
> +  IMPL (__fpclassify_builtin),
> +  IMPL (fpclassify),
> +
> +  IMPL (remainder_test1),
> +  IMPL (remainder_test2)
> +};
> +
> +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");

Use the TEST_NAME macro.

> +
> +  /* 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.  */

How do you know that this is the ratio of generated inputs?  Please
enhance the comment to describe that.

> +
> +  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"
>  
>  #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 ();
>  
>    memset (&runtime, 0, sizeof (runtime));
>  
> diff --git a/benchtests/bench-util.h b/benchtests/bench-util.h
> new file mode 100644
> index 0000000..930cecc
> --- /dev/null
> +++ b/benchtests/bench-util.h
> @@ -0,0 +1,28 @@
> +/* 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);
diff mbox

Patch

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)
 
 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..1251935
--- /dev/null
+++ b/benchtests/bench-math-inlines.c
@@ -0,0 +1,284 @@ 
+/* Measure math inline 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/>.  */
+
+#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>
+
+#define BOOLTEST(func)					  \
+int __attribute__((noinline))				  \
+func ## _f (double d, int i)				  \
+{							  \
+  if (func (d))						  \
+    return (int)d + i;					  \
+  else							  \
+    return 5;						  \
+}							  \
+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++)				  \
+      if (func ## _f (p[i] * 2.0, i))			  \
+	res += 5;					  \
+  return res;						  \
+}
+
+#define VALUETEST(func)					  \
+int __attribute__((noinline))				  \
+func ## _f (double d)					  \
+{							  \
+  return func (d);					  \
+}							  \
+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++)				  \
+      res += func ## _f (p[i] * 2.0);			  \
+  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)
+
+/* Inlines similar to existing 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
+__isinf_ns (double d)
+{
+  uint64_t di;
+  EXTRACT_WORDS64 (di, d);
+  return (di & 0x7fffffffffffffffull) == 0x7ff0000000000000ull;
+}
+extern __always_inline int
+__finite_inl (double d)
+{
+  uint64_t di;
+  EXTRACT_WORDS64 (di, d);
+  return (di & 0x7fffffffffffffffull) < 0x7ff0000000000000ull;
+}
+
+#define __isnormal_inl(X) (__fpclassify (X) == FP_NORMAL)
+
+/* Inlines for the builtin functions.  */
+
+#define __isnan_builtin(X) __builtin_isnan (X)
+#define __isinf_ns_builtin(X) __builtin_isinf (X)
+#define __isinf_builtin(X) __builtin_isinf_sign (X)
+#define __isfinite_builtin(X) __builtin_isfinite (X)
+#define __isnormal_builtin(X) __builtin_isnormal (X)
+#define __fpclassify_builtin(X) __builtin_fpclassify (FP_NAN, FP_INFINITE,  \
+				  FP_NORMAL, FP_SUBNORMAL, FP_ZERO, (X))
+
+double __attribute ((noinline))
+kernel_standard (double x, double y, int z)
+{
+  return x * y + z;
+}
+
+volatile double rem1 = 2.5;
+
+extern __always_inline double
+remainder_test1 (double x)
+{
+  double y = rem1;
+  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);
+}
+
+extern __always_inline double
+remainder_test2 (double x)
+{
+  double y = rem1;
+  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);
+}
+
+/* Create test functions for each possibility.  */
+
+BOOLTEST (__isnan)
+BOOLTEST (__isnan_inl)
+BOOLTEST (__isnan_builtin)
+BOOLTEST (isnan)
+
+BOOLTEST (__isinf)
+BOOLTEST (__isinf_builtin)
+BOOLTEST (__isinf_ns)
+BOOLTEST (__isinf_ns_builtin)
+BOOLTEST (isinf)
+
+BOOLTEST (__finite)
+BOOLTEST (__finite_inl)
+BOOLTEST (__isfinite_builtin)
+BOOLTEST (isfinite)
+
+BOOLTEST (__isnormal_inl)
+BOOLTEST (__isnormal_builtin)
+BOOLTEST (isnormal)
+
+VALUETEST (__fpclassify)
+VALUETEST (__fpclassify_builtin)
+VALUETEST (fpclassify)
+
+VALUETEST (remainder_test1)
+VALUETEST (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 ## _t }
+
+impl_t test_list[] =
+{
+  IMPL (__isnan),
+  IMPL (__isnan_inl),
+  IMPL (__isnan_builtin),
+  IMPL (isnan),
+
+  IMPL (__isinf),
+  IMPL (__isinf_ns),
+  IMPL (__isinf_ns_builtin),
+  IMPL (__isinf_builtin),
+  IMPL (isinf),
+
+  IMPL (__finite),
+  IMPL (__finite_inl),
+  IMPL (__isfinite_builtin),
+  IMPL (isfinite),
+
+  IMPL (__isnormal_inl),
+  IMPL (__isnormal_builtin),
+  IMPL (isnormal),
+
+  IMPL (__fpclassify),
+  IMPL (__fpclassify_builtin),
+  IMPL (fpclassify),
+
+  IMPL (remainder_test1),
+  IMPL (remainder_test2)
+};
+
+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"
 
 #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 ();
 
   memset (&runtime, 0, sizeof (runtime));
 
diff --git a/benchtests/bench-util.h b/benchtests/bench-util.h
new file mode 100644
index 0000000..930cecc
--- /dev/null
+++ b/benchtests/bench-util.h
@@ -0,0 +1,28 @@ 
+/* 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);
-- 
1.9.1

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;
+}