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glibc/sysdeps/aarch64/hp-timing.h

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AArch64: Add hp-timing.h Add hp-timing.h using the cntvct_el0 counter. Return timing in nanoseconds so it is fully compatible with generic hp-timing. Don't set HP_TIMING_INLINE in the dynamic linker since it adds unnecessary overheads and some ancient kernels may not handle emulating cntcvt correctly. Currently cntvct_el0 is only used for timing in the benchtests. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-07-01 14:42:05 +00:00
/* High precision, low overhead timing functions. AArch64 version.
Update copyright dates with scripts/update-copyrights
2023-01-06 21:08:04 +00:00
Copyright (C) 2021-2023 Free Software Foundation, Inc.
AArch64: Add hp-timing.h Add hp-timing.h using the cntvct_el0 counter. Return timing in nanoseconds so it is fully compatible with generic hp-timing. Don't set HP_TIMING_INLINE in the dynamic linker since it adds unnecessary overheads and some ancient kernels may not handle emulating cntcvt correctly. Currently cntvct_el0 is only used for timing in the benchtests. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-07-01 14:42:05 +00:00
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/>. */
#ifndef _HP_TIMING_H
#define _HP_TIMING_H 1
#include <time.h>
#include <stdint.h>
#include <hp-timing-common.h>
#include <libc-symbols.h>
/* Don't use inline timer in ld.so. */
#if IS_IN(rtld)
# define HP_TIMING_INLINE (0)
#else
# define HP_TIMING_INLINE (1)
#endif
typedef uint64_t hp_timing_t;
#define HP_TIMING_NOW(var) \
__asm__ __volatile__ ("isb; mrs %0, cntvct_el0" : "=r" (var))
/* Compute elapsed time in nanoseconds. */
#undef HP_TIMING_DIFF
#define HP_TIMING_DIFF(Diff, Start, End) \
({ hp_timing_t freq; \
__asm__ __volatile__ ("mrs %0, cntfrq_el0" : "=r" (freq)); \
AArch64: Fix HP_TIMING_DIFF computation [BZ# 29329] Fix the computation to allow for cntfrq_el0 being larger than 1GHz. Assume cntfrq_el0 is a multiple of 1MHz to increase the maximum interval (1024 seconds at 1GHz). Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
2023-02-22 16:45:59 +00:00
(Diff) = (((End) - (Start)) * UINT64_C(1000000000 >> 6)) / (freq >> 6); \
AArch64: Add hp-timing.h Add hp-timing.h using the cntvct_el0 counter. Return timing in nanoseconds so it is fully compatible with generic hp-timing. Don't set HP_TIMING_INLINE in the dynamic linker since it adds unnecessary overheads and some ancient kernels may not handle emulating cntcvt correctly. Currently cntvct_el0 is only used for timing in the benchtests. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-07-01 14:42:05 +00:00
})
#endif /* hp-timing.h */
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