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5c22fd25c1
The CORE-MATH implementation is correctly rounded (for any rounding mode)
and shows better performance compared to the generic exp2m1f.
The code was adapted to glibc style and to use the definition of
math_config.h (to handle errno, overflow, and underflow). The
only change is to handle FLT_MAX_EXP for FE_DOWNWARD or FE_TOWARDZERO.
The benchmark inputs are based on exp2f ones.
Benchtest on x64_64 (Ryzen 9 5900X, gcc 14.2.1), aarch64 (Neoverse-N1,
gcc 13.3.1), and powerpc (POWER10, gcc 13.2.1):
Latency master patched improvement
x86_64 40.6042 48.7104 -19.96%
x86_64v2 40.7506 35.9032 11.90%
x86_64v3 35.2301 31.7956 9.75%
i686 102.094 94.6657 7.28%
aarch64 18.2704 15.1387 17.14%
power10 11.9444 8.2402 31.01%
reciprocal-throughput master patched improvement
x86_64 20.8683 16.1428 22.64%
x86_64v2 19.5076 10.4474 46.44%
x86_64v3 19.2106 10.4014 45.86%
i686 56.4054 59.3004 -5.13%
aarch64 12.0781 7.3953 38.77%
power10 6.5306 5.9388 9.06%
The generic implementation calls __ieee754_exp2f and x86_64 provides
an optimized ifunc version (built with -mfma -mavx2, not correctly
rounded). This explains the performance difference for x86_64.
Same for i686, where the ABI provides an optimized __ieee754_exp2f
version built with '-msse2 -mfpmath=sse'. When built wth same
flags, the new algorithm shows a better performance:
master patched improvement
latency 102.094 91.2823 10.59%
reciprocal-throughput 56.4054 52.7984 6.39%
Signed-off-by: Alexei Sibidanov <sibid@uvic.ca>
Signed-off-by: Paul Zimmermann <Paul.Zimmermann@inria.fr>
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: DJ Delorie <dj@redhat.com>
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| bits | ||
| catgets | ||
| ChangeLog.old | ||
| conform | ||
| csu | ||
| ctype | ||
| debug | ||
| dirent | ||
| dlfcn | ||
| elf | ||
| gmon | ||
| gnulib | ||
| hesiod | ||
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| iconv | ||
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| include | ||
| inet | ||
| intl | ||
| io | ||
| libio | ||
| locale | ||
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| login | ||
| mach | ||
| malloc | ||
| manual | ||
| math | ||
| mathvec | ||
| misc | ||
| nis | ||
| nptl | ||
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| po | ||
| posix | ||
| resolv | ||
| resource | ||
| rt | ||
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| socket | ||
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| stdio-common | ||
| stdlib | ||
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| sunrpc | ||
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| time | ||
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| .gitignore | ||
| abi-tags | ||
| aclocal.m4 | ||
| config.h.in | ||
| config.make.in | ||
| configure | ||
| configure.ac | ||
| CONTRIBUTED-BY | ||
| COPYING | ||
| COPYING.LIB | ||
| extra-lib.mk | ||
| gen-locales.mk | ||
| INSTALL | ||
| libc-abis | ||
| libof-iterator.mk | ||
| LICENSES | ||
| MAINTAINERS | ||
| Makeconfig | ||
| Makefile | ||
| Makefile.help | ||
| Makefile.in | ||
| Makerules | ||
| NEWS | ||
| o-iterator.mk | ||
| README | ||
| Rules | ||
| SECURITY.md | ||
| SHARED-FILES | ||
| shlib-versions | ||
| test-skeleton.c | ||
| version.h | ||
This directory contains the sources of the GNU C Library. See the file "version.h" for what release version you have. The GNU C Library is the standard system C library for all GNU systems, and is an important part of what makes up a GNU system. It provides the system API for all programs written in C and C-compatible languages such as C++ and Objective C; the runtime facilities of other programming languages use the C library to access the underlying operating system. In GNU/Linux systems, the C library works with the Linux kernel to implement the operating system behavior seen by user applications. In GNU/Hurd systems, it works with a microkernel and Hurd servers. The GNU C Library implements much of the POSIX.1 functionality in the GNU/Hurd system, using configurations i[4567]86-*-gnu and x86_64-gnu. When working with Linux kernels, this version of the GNU C Library requires Linux kernel version 3.2 or later. Also note that the shared version of the libgcc_s library must be installed for the pthread library to work correctly. The GNU C Library supports these configurations for using Linux kernels: aarch64*-*-linux-gnu alpha*-*-linux-gnu arc*-*-linux-gnu arm-*-linux-gnueabi csky-*-linux-gnuabiv2 hppa-*-linux-gnu i[4567]86-*-linux-gnu x86_64-*-linux-gnu Can build either x86_64 or x32 loongarch64-*-linux-gnu Hardware floating point, LE only. m68k-*-linux-gnu microblaze*-*-linux-gnu mips-*-linux-gnu mips64-*-linux-gnu or1k-*-linux-gnu powerpc-*-linux-gnu Hardware or software floating point, BE only. powerpc64*-*-linux-gnu Big-endian and little-endian. s390-*-linux-gnu s390x-*-linux-gnu riscv32-*-linux-gnu riscv64-*-linux-gnu sh[34]-*-linux-gnu sparc*-*-linux-gnu sparc64*-*-linux-gnu If you are interested in doing a port, please contact the glibc maintainers; see https://www.gnu.org/software/libc/ for more information. See the file INSTALL to find out how to configure, build, and install the GNU C Library. You might also consider reading the WWW pages for the C library at https://www.gnu.org/software/libc/. The GNU C Library is (almost) completely documented by the Texinfo manual found in the `manual/' subdirectory. The manual is still being updated and contains some known errors and omissions; we regret that we do not have the resources to work on the manual as much as we would like. For corrections to the manual, please file a bug in the `manual' component, following the bug-reporting instructions below. Please be sure to check the manual in the current development sources to see if your problem has already been corrected. Please see https://www.gnu.org/software/libc/bugs.html for bug reporting information. We are now using the Bugzilla system to track all bug reports. This web page gives detailed information on how to report bugs properly. The GNU C Library is free software. See the file COPYING.LIB for copying conditions, and LICENSES for notices about a few contributions that require these additional notices to be distributed. License copyright years may be listed using range notation, e.g., 1996-2015, indicating that every year in the range, inclusive, is a copyrightable year that would otherwise be listed individually.