1 /* Pthread mutex backoff configuration.
2 Copyright (C) 2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18 #ifndef _PTHREAD_MUTEX_BACKOFF_H
19 #define _PTHREAD_MUTEX_BACKOFF_H 1
20
21 #include <fast-jitter.h>
22
23 static inline unsigned int
get_jitter(void)24 get_jitter (void)
25 {
26 return get_fast_jitter ();
27 }
28
29 #define MAX_BACKOFF 16
30
31 static inline int
get_next_backoff(int backoff)32 get_next_backoff (int backoff)
33 {
34 /* Binary expontial backoff. Limiting max backoff
35 can reduce latency in large critical section. */
36 return (backoff < MAX_BACKOFF) ? backoff << 1 : backoff;
37 }
38
39 #endif
40