mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-29 05:51:10 +00:00
43 lines
1.4 KiB
C
43 lines
1.4 KiB
C
/* Fallback for fast jitter just return 0.
|
|
Copyright (C) 2019-2023 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
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#ifndef _FAST_JITTER_H
|
|
# define _FAST_JITTER_H
|
|
|
|
# include <stdint.h>
|
|
# include <hp-timing.h>
|
|
|
|
/* Baseline just return 0. We could create jitter using a clock or
|
|
'random_bits' but that may imply a syscall and the goal of
|
|
'get_fast_jitter' is minimal overhead "randomness" when such
|
|
randomness helps performance. Adding high overhead the function
|
|
defeats the purpose. */
|
|
static inline uint32_t
|
|
get_fast_jitter (void)
|
|
{
|
|
# if HP_TIMING_INLINE
|
|
hp_timing_t jitter;
|
|
HP_TIMING_NOW (jitter);
|
|
return (uint32_t) jitter;
|
|
# else
|
|
return 0;
|
|
# endif
|
|
}
|
|
|
|
#endif
|