Re: [PATCH] PowerPC: modf optimization

[Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>]

Ping.

On 08-04-2013 15:29, Adhemerval Zanella wrote:
> Ping.
>
> On 03/31/2013 06:56 PM, Adhemerval Zanella wrote:
>> On 03/27/2013 11:11 AM, Andreas Jaeger wrote:
>>> I'm fine with the benchtests addition (see one comment below).
>>>
>>> I'm not sure about the __ceil, __floor issue and would like feedback from others on how to handle this,
>> I have added the copyright header and I changed to patch to use the new modf
>> implementation for POWER5 or higher only, making the s_floor and s_ceil addition
>> not required anymore.
>>
>> I also increased the iterations to 5e8 and I got the following results in a POWER7
>> machine with 64 bits:
>>
>> MASTER: modf: ITERS:5e+08: TOTAL:5.96664s, MAX:42.302ns, MIN:9.104ns, 8.37993e+07 iter/s
>> PATCH:  modf: ITERS:5e+08: TOTAL:3.00147s, MAX:40.334ns, MIN:5.63ns,  1.66585e+08 iter/s
>>
>> And clock_gettime is an vDSO for PowerPC, however afaik CLOCK_PROCESS_CPUTIME_ID
>> fall-back to a syscall even for x86_64. Maybe we should increase the default
>> iterations for all benchtests.
>>
>> Any tips, comments, advices?
>>
>> ---
>>
>> 2013-03-31  Adhemerval Zanella  <azanella@linux.vnet.ibm.com>
>>
>>     * sysdeps/powerpc/fpu/s_modf.c: New file: modf optimization for POWER.
>>     * sysdeps/powerpc/fpu/s_modff.c: New file: modff optimization for POWER.
>>     * sysdeps/powerpc/powerpc64/power5/Implies: Add powerpc/power5 and
>>     powerpc/power5/fpu folders.
>>     * sysdeps/powerpc/powerpc32/power5/Implies: Likewise.
>>     * benchtests/Makefile: Add modf testcase.
>>     * benchtests/bench-modf.c: New file: Benchmark test for modf.
>>
>> --
>>
>> diff --git a/benchtests/Makefile b/benchtests/Makefile
>> index 74938b9..dbbc44c 100644
>> --- a/benchtests/Makefile
>> +++ b/benchtests/Makefile
>> @@ -43,7 +43,7 @@
>>  #   See pow-inputs for an example.
>>
>>  subdir := benchtests
>> -bench := exp pow
>> +bench := exp pow modf
>>
>>  exp-ITER = 100000
>>  exp-ARGLIST = double
>> diff --git a/benchtests/bench-modf.c b/benchtests/bench-modf.c
>> new file mode 100644
>> index 0000000..1f91556
>> --- /dev/null
>> +++ b/benchtests/bench-modf.c
>> @@ -0,0 +1,27 @@
>> +/* Copyright (C) 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/>.  */
>> +
>> +extern double modf ( double, double*);
>> +#define CALL_BENCH_FUNC(j, i) modf ( in[j].arg0, &i);
>> +struct args { double arg0; } in[] = {{42.42}, {-42.42}
>> +};
>> +#define NUM_SAMPLES (sizeof (in) / sizeof (struct args))
>> +static volatile double ret = 0.0;
>> +#define BENCH_FUNC(j) ({double iptr; ret =  CALL_BENCH_FUNC (j, iptr);})
>> +#define ITER 250000000
>> +#define FUNCNAME "modf"
>> +#include "bench-skeleton.c"
>> diff --git a/sysdeps/powerpc/power5/fpu/s_modf.c b/sysdeps/powerpc/power5/fpu/s_modf.c
>> new file mode 100644
>> index 0000000..b45bf66
>> --- /dev/null
>> +++ b/sysdeps/powerpc/power5/fpu/s_modf.c
>> @@ -0,0 +1,58 @@
>> +/* Copyright (C) 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 Library General Public License as
>> +   published by the Free Software Foundation; either version 2 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
>> +   Library General Public License for more details.
>> +
>> +   You should have received a copy of the GNU Library General Public
>> +   License along with the GNU C Library; see the file COPYING.LIB.  If
>> +   not, see <http://www.gnu.org/licenses/>.  */
>> +
>> +#include <math.h>
>> +#include <math_private.h>
>> +#include <math_ldbl_opt.h>
>> +
>> +double
>> +__modf (double x, double *iptr)
>> +{
>> +  if (__builtin_isinf (x))
>> +    {
>> +      *iptr = x;
>> +      return __copysign (0.0, x);
>> +    }
>> +  else if (__builtin_isnan (x))
>> +    {
>> +      *iptr = NAN;
>> +      return NAN;
>> +    }
>> +
>> +  if (x >= 0.0)
>> +    {
>> +      *iptr = __floor (x);
>> +      return (x - *iptr);
>> +    }
>> +  else
>> +    {
>> +      *iptr = __ceil (x);
>> +      return (x - *iptr);
>> +    }
>> +}
>> +weak_alias (__modf, modf)
>> +#ifdef NO_LONG_DOUBLE
>> +strong_alias (__modf, __modfl)
>> +weak_alias (__modf, modfl)
>> +#endif
>> +#ifdef IS_IN_libm
>> +# if LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)
>> +compat_symbol (libm, __modf, modfl, GLIBC_2_0);
>> +# endif
>> +#elif LONG_DOUBLE_COMPAT(libc, GLIBC_2_0)
>> +compat_symbol (libc, __modf, modfl, GLIBC_2_0);
>> +#endif
>> diff --git a/sysdeps/powerpc/power5/fpu/s_modff.c b/sysdeps/powerpc/power5/fpu/s_modff.c
>> new file mode 100644
>> index 0000000..55759cd
>> --- /dev/null
>> +++ b/sysdeps/powerpc/power5/fpu/s_modff.c
>> @@ -0,0 +1,46 @@
>> +/* Copyright (C) 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 Library General Public License as
>> +   published by the Free Software Foundation; either version 2 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
>> +   Library General Public License for more details.
>> +
>> +   You should have received a copy of the GNU Library General Public
>> +   License along with the GNU C Library; see the file COPYING.LIB.  If
>> +   not, see <http://www.gnu.org/licenses/>.  */
>> +
>> +#include <math.h>
>> +#include <math_private.h>
>> +
>> +float
>> +__modff (float x, float *iptr)
>> +{
>> +  if (__builtin_isinff (x))
>> +    {
>> +      *iptr = x;
>> +      return __copysignf (0.0, x);
>> +    }
>> +  else if (__builtin_isnanf (x))
>> +    {
>> +      *iptr = NAN;
>> +      return NAN;
>> +    }
>> +
>> +  if (x >= 0.0)
>> +    {
>> +      *iptr = __floorf (x);
>> +      return (x - *iptr);
>> +    }
>> +  else
>> +    {
>> +      *iptr = __ceilf (x);
>> +      return (x - *iptr);
>> +    }
>> +}
>> +weak_alias (__modff, modff)
>> diff --git a/sysdeps/powerpc/powerpc32/power5/Implies b/sysdeps/powerpc/powerpc32/power5/Implies
>> index 17139bf..17949d4 100644
>> --- a/sysdeps/powerpc/powerpc32/power5/Implies
>> +++ b/sysdeps/powerpc/powerpc32/power5/Implies
>> @@ -1,2 +1,4 @@
>> +powerpc/power5/fpu
>> +powerpc/power5
>>  powerpc/powerpc32/power4/fpu
>>  powerpc/powerpc32/power4
>> diff --git a/sysdeps/powerpc/powerpc64/power5/Implies b/sysdeps/powerpc/powerpc64/power5/Implies
>> index bedb20b..b36831e 100644
>> --- a/sysdeps/powerpc/powerpc64/power5/Implies
>> +++ b/sysdeps/powerpc/powerpc64/power5/Implies
>> @@ -1,2 +1,4 @@
>> +powerpc/power5/fpu
>> +powerpc/power5
>>  powerpc/powerpc64/power4/fpu
>>  powerpc/powerpc64/power4
>>