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6a34c928c2
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>
48 lines
1.5 KiB
C
48 lines
1.5 KiB
C
/* High precision, low overhead timing functions. AArch64 version.
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Copyright (C) 2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _HP_TIMING_H
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#define _HP_TIMING_H 1
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#include <time.h>
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#include <stdint.h>
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#include <hp-timing-common.h>
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#include <libc-symbols.h>
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/* Don't use inline timer in ld.so. */
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#if IS_IN(rtld)
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# define HP_TIMING_INLINE (0)
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#else
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# define HP_TIMING_INLINE (1)
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#endif
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typedef uint64_t hp_timing_t;
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#define HP_TIMING_NOW(var) \
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__asm__ __volatile__ ("isb; mrs %0, cntvct_el0" : "=r" (var))
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/* Compute elapsed time in nanoseconds. */
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#undef HP_TIMING_DIFF
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#define HP_TIMING_DIFF(Diff, Start, End) \
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({ hp_timing_t freq; \
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__asm__ __volatile__ ("mrs %0, cntfrq_el0" : "=r" (freq)); \
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(Diff) = ((End) - (Start)) * (UINT64_C(1000000000) / freq); \
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})
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#endif /* hp-timing.h */
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