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| author | H.J. Lu <hjl.tools@gmail.com> | 2018-10-17 15:16:38 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2018-10-17 15:16:45 -0700 |
| commit | 72771e53753647111d31c5c4bf43d8901e6baf7e (patch) | |
| tree | 66c4a0605d4624372f8e6742bf0c417ceaba8d43 /sysdeps/x86/hp-timing.h | |
| parent | c2b7ccad93d6361eba91755e8f0c92e97c76e854 (diff) | |
| download | glibc-72771e53753647111d31c5c4bf43d8901e6baf7e.tar glibc-72771e53753647111d31c5c4bf43d8901e6baf7e.tar.gz glibc-72771e53753647111d31c5c4bf43d8901e6baf7e.tar.bz2 glibc-72771e53753647111d31c5c4bf43d8901e6baf7e.zip | |
x86: Use _rdtsc intrinsic for HP_TIMING_NOW
Since _rdtsc intrinsic is supported in GCC 4.9, we can use it for
HP_TIMING_NOW. This patch
1. Create x86 hp-timing.h to replace i686 and x86_64 hp-timing.h.
2. Move MINIMUM_ISA from init-arch.h to isa.h so that x86 hp-timing.h
can check minimum x86 ISA to decide if _rdtsc can be used.
NB: Checking if __i686__ isn't sufficient since __i686__ may not be
defined when building for i686 class processors.
* sysdeps/i386/init-arch.h: Removed.
* sysdeps/i386/i586/init-arch.h: Likewise.
* sysdeps/i386/i686/init-arch.h: Likewise.
* sysdeps/i386/i686/hp-timing.h: Likewise.
* sysdeps/x86_64/hp-timing.h: Likewise.
* sysdeps/i386/isa.h: New file.
* sysdeps/i386/i586/isa.h: Likewise.
* sysdeps/i386/i686/isa.h: Likewise.
* sysdeps/x86_64/isa.h: Likewise.
* sysdeps/x86/hp-timing.h: New file.
* sysdeps/x86/init-arch.h: Include <isa.h>.
Diffstat (limited to 'sysdeps/x86/hp-timing.h')
| -rw-r--r-- | sysdeps/x86/hp-timing.h | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/sysdeps/x86/hp-timing.h b/sysdeps/x86/hp-timing.h new file mode 100644 index 0000000000..1c20e9d828 --- /dev/null +++ b/sysdeps/x86/hp-timing.h @@ -0,0 +1,52 @@ +/* High precision, low overhead timing functions. x86 version. + Copyright (C) 2018 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 _HP_TIMING_H +#define _HP_TIMING_H 1 + +#include <isa.h> + +#if MINIMUM_ISA == 686 || MINIMUM_ISA == 8664 +# include <x86intrin.h> + +/* We always assume having the timestamp register. */ +# define HP_TIMING_AVAIL (1) +# define HP_SMALL_TIMING_AVAIL (1) + +/* We indeed have inlined functions. */ +# define HP_TIMING_INLINE (1) + +/* We use 64bit values for the times. */ +typedef unsigned long long int hp_timing_t; + +/* That's quite simple. Use the `rdtsc' instruction. Note that the value + might not be 100% accurate since there might be some more instructions + running in this moment. This could be changed by using a barrier like + 'cpuid' right before the `rdtsc' instruciton. But we are not interested + in accurate clock cycles here so we don't do this. */ +# define HP_TIMING_NOW(Var) ((Var) = _rdtsc ()) + +# include <hp-timing-common.h> +#else +/* NB: Undefine _HP_TIMING_H so that <sysdeps/generic/hp-timing.h> will + be included. */ +# undef _HP_TIMING_H +# include <sysdeps/generic/hp-timing.h> +#endif + +#endif /* hp-timing.h */ |