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43 lines
1.4 KiB
C
43 lines
1.4 KiB
C
/* Fallback for fast jitter just return 0.
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Copyright (C) 2019-2023 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 _FAST_JITTER_H
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# define _FAST_JITTER_H
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# include <stdint.h>
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# include <hp-timing.h>
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/* Baseline just return 0. We could create jitter using a clock or
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'random_bits' but that may imply a syscall and the goal of
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'get_fast_jitter' is minimal overhead "randomness" when such
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randomness helps performance. Adding high overhead the function
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defeats the purpose. */
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static inline uint32_t
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get_fast_jitter (void)
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{
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# if HP_TIMING_INLINE
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hp_timing_t jitter;
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HP_TIMING_NOW (jitter);
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return (uint32_t) jitter;
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# else
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return 0;
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# endif
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}
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#endif
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