glibc/sysdeps/x86_64/nptl/pthread_mutex_backoff.h

40 lines
1.2 KiB
C

/* Pthread mutex backoff configuration.
Copyright (C) 2022-2023 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 _PTHREAD_MUTEX_BACKOFF_H
#define _PTHREAD_MUTEX_BACKOFF_H 1
#include <fast-jitter.h>
static inline unsigned int
get_jitter (void)
{
return get_fast_jitter ();
}
#define MAX_BACKOFF 16
static inline int
get_next_backoff (int backoff)
{
/* Binary expontial backoff. Limiting max backoff
can reduce latency in large critical section. */
return (backoff < MAX_BACKOFF) ? backoff << 1 : backoff;
}
#endif