[PATCH] x86_64: Add asinh with FMA

[H.J. Lu]

On Thu, Mar 13, 2025 at 8:50 PM Sunil Pandey <skpgkp2@gmail.com> wrote:
>
>
>
> On Thu, Mar 13, 2025 at 6:04 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>>
>> On Thu, Mar 13, 2025 at 5:27 PM Sunil K Pandey <skpgkp2@gmail.com> wrote:
>> >
>> > FMA and non-FMA performance are similar on SPR.
>> >
>> >                         Before          After           Improvement
>> > reciprocal-throughput   12.226          12.4064         -1%
>> > latency                 49.4701         48.4424         2%
>>
>> Since there is no real advantage for FMA, it isn't necessary.
>>
>
> This request comes from https://issues.redhat.com/browse/RHEL-1063
> We don't see any real advantage because in upstream glibc underlying
> function call
>
> __ieee754_log
> __log1p
>
> are already FMA enabled and invoked via ifunc.
>
> FMA version could be beneficial if the underlying function is replaced
> by direct call.

Please do that to see if it improves performance.

Thanks.

>
>
>>
>> > ---
>> >  benchtests/asinh-inputs                    |  1 +
>> >  sysdeps/ieee754/dbl-64/s_asinh.c           |  5 ++++
>> >  sysdeps/x86_64/fpu/multiarch/Makefile      |  2 ++
>> >  sysdeps/x86_64/fpu/multiarch/s_asinh-fma.c |  7 +++++
>> >  sysdeps/x86_64/fpu/multiarch/s_asinh.c     | 31 ++++++++++++++++++++++
>> >  5 files changed, 46 insertions(+)
>> >  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_asinh-fma.c
>> >  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_asinh.c
>> >
>> > diff --git a/benchtests/asinh-inputs b/benchtests/asinh-inputs
>> > index 8dfa37c49f..946e7b4d22 100644
>> > --- a/benchtests/asinh-inputs
>> > +++ b/benchtests/asinh-inputs
>> > @@ -1,6 +1,7 @@
>> >  ## args: double
>> >  ## ret: double
>> >  ## includes: math.h
>> > +## name: workload-random
>> >  0x1.408fb643484cep-11
>> >  0x1.f0763423f1d52p-23
>> >  -0x1.681573418e494p4
>> > diff --git a/sysdeps/ieee754/dbl-64/s_asinh.c b/sysdeps/ieee754/dbl-64/s_asinh.c
>> > index 7fd281d791..04b686a28e 100644
>> > --- a/sysdeps/ieee754/dbl-64/s_asinh.c
>> > +++ b/sysdeps/ieee754/dbl-64/s_asinh.c
>> > @@ -32,6 +32,11 @@ static const double
>> >    ln2 = 6.93147180559945286227e-01, /* 0x3FE62E42, 0xFEFA39EF */
>> >    huge = 1.00000000000000000000e+300;
>> >
>> > +#ifndef SECTION
>> > +# define SECTION
>> > +#endif
>> > +
>> > +SECTION
>> >  double
>> >  __asinh (double x)
>> >  {
>> > diff --git a/sysdeps/x86_64/fpu/multiarch/Makefile b/sysdeps/x86_64/fpu/multiarch/Makefile
>> > index 3403422443..1ab46bb446 100644
>> > --- a/sysdeps/x86_64/fpu/multiarch/Makefile
>> > +++ b/sysdeps/x86_64/fpu/multiarch/Makefile
>> > @@ -7,6 +7,7 @@ CFLAGS-e_log-fma.c = -mfma -mavx2
>> >  CFLAGS-e_log2-fma.c = -mfma -mavx2
>> >  CFLAGS-e_pow-fma.c = -mfma -mavx2
>> >  CFLAGS-e_sinh-fma.c = -mfma -mavx2
>> > +CFLAGS-s_asinh-fma.c = -mfma -mavx2
>> >  CFLAGS-s_atan-fma.c = -mfma -mavx2
>> >  CFLAGS-s_expm1-fma.c = -mfma -mavx2
>> >  CFLAGS-s_log1p-fma.c = -mfma -mavx2
>> > @@ -73,6 +74,7 @@ libm-sysdep_routines += \
>> >    e_pow-fma \
>> >    e_powf-fma \
>> >    e_sinh-fma \
>> > +  s_asinh-fma \
>> >    s_atan-avx \
>> >    s_atan-fma \
>> >    s_ceil-sse4_1 \
>> > diff --git a/sysdeps/x86_64/fpu/multiarch/s_asinh-fma.c b/sysdeps/x86_64/fpu/multiarch/s_asinh-fma.c
>> > new file mode 100644
>> > index 0000000000..293a255005
>> > --- /dev/null
>> > +++ b/sysdeps/x86_64/fpu/multiarch/s_asinh-fma.c
>> > @@ -0,0 +1,7 @@
>> > +#define __asinh __asinh_fma
>> > +#define __ieee754_log __ieee754_log_fma
>> > +#define __log1p __log1p_fma
>> > +
>> > +#define SECTION __attribute__ ((section (".text.fma")))
>> > +
>> > +#include <sysdeps/ieee754/dbl-64/s_asinh.c>
>> > diff --git a/sysdeps/x86_64/fpu/multiarch/s_asinh.c b/sysdeps/x86_64/fpu/multiarch/s_asinh.c
>> > new file mode 100644
>> > index 0000000000..509d74c96b
>> > --- /dev/null
>> > +++ b/sysdeps/x86_64/fpu/multiarch/s_asinh.c
>> > @@ -0,0 +1,31 @@
>> > +/* Multiple versions of asinh.
>> > +   Copyright (C) 2025 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
>> > +   <https://www.gnu.org/licenses/>.  */
>> > +
>> > +#include <sysdeps/x86/isa-level.h>
>> > +#if MINIMUM_X86_ISA_LEVEL < AVX2_X86_ISA_LEVEL
>> > +
>> > +extern double __redirect_asinh (double);
>> > +
>> > +# define SYMBOL_NAME asinh
>> > +# include "ifunc-fma.h"
>> > +
>> > +libc_ifunc_redirected (__redirect_asinh, __asinh, IFUNC_SELECTOR ());
>> > +
>> > +# define __asinh __asinh_sse2
>> > +#endif
>> > +#include <sysdeps/ieee754/dbl-64/s_asinh.c>
>> > --
>> > 2.48.1
>> >
>>
>>
>> --
>> H.J.
>
>
>



-- 
H.J.