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freebsd-nq/include/pthread.h
Kris Kennaway 2017a7cdfe Add a new "non-portable" mutex type, PTHREAD_MUTEX_ADAPTIVE_NP. This 
is also implemented in glibc and is used by a number of existing
applications (mysql, firefox, etc).

This mutex type is a default mutex with the additional property that
it spins briefly when attempting to acquire a contested lock, doing
trylock operations in userland before entering the kernel to block if
eventually unsuccessful.

The expectation is that applications requesting this mutex type know
that the mutex is likely to be only held for very brief periods, so it
is faster to spin in userland and probably succeed in acquiring the
mutex, than to enter the kernel and sleep, only to be woken up almost
immediately.  This can help significantly in certain cases when
pthread mutexes are heavily contended and held for brief durations
(such as mysql).

Spin up to 200 times before entering the kernel, which represents only
a few us on modern CPUs.  No performance degradation was observed with
this value and it is sufficient to avoid a large performance drop in
mysql performance in the heavily contended pthread mutex case.

The libkse implementation is a NOP.

Reviewed by:      jeff
MFC after:        3 days
2007-10-29 21:01:47 +00:00

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/*
* Copyright (c) 1993, 1994 by Chris Provenzano, proven@mit.edu
* Copyright (c) 1995-1998 by John Birrell <jb@cimlogic.com.au>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Chris Provenzano.
* 4. The name of Chris Provenzano may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL CHRIS PROVENZANO BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _PTHREAD_H_
#define _PTHREAD_H_
/*
* Header files.
*/
#include <sys/cdefs.h>
#include <sys/_pthreadtypes.h>
#include <machine/_limits.h>
#include <machine/_types.h>
#include <sys/_sigset.h>
#include <sched.h>
#include <time.h>
/*
* Run-time invariant values:
*/
#define PTHREAD_DESTRUCTOR_ITERATIONS 4
#define PTHREAD_KEYS_MAX 256
#define PTHREAD_STACK_MIN __MINSIGSTKSZ
#define PTHREAD_THREADS_MAX __ULONG_MAX
#define PTHREAD_BARRIER_SERIAL_THREAD -1
/*
* Flags for threads and thread attributes.
*/
#define PTHREAD_DETACHED 0x1
#define PTHREAD_SCOPE_SYSTEM 0x2
#define PTHREAD_INHERIT_SCHED 0x4
#define PTHREAD_NOFLOAT 0x8
#define PTHREAD_CREATE_DETACHED PTHREAD_DETACHED
#define PTHREAD_CREATE_JOINABLE 0
#define PTHREAD_SCOPE_PROCESS 0
#define PTHREAD_EXPLICIT_SCHED 0
/*
* Flags for read/write lock attributes
*/
#define PTHREAD_PROCESS_PRIVATE 0
#define PTHREAD_PROCESS_SHARED 1
/*
* Flags for cancelling threads
*/
#define PTHREAD_CANCEL_ENABLE 0
#define PTHREAD_CANCEL_DISABLE 1
#define PTHREAD_CANCEL_DEFERRED 0
#define PTHREAD_CANCEL_ASYNCHRONOUS 2
#define PTHREAD_CANCELED ((void *) 1)
/*
* Flags for once initialization.
*/
#define PTHREAD_NEEDS_INIT 0
#define PTHREAD_DONE_INIT 1
/*
* Static once initialization values.
*/
#define PTHREAD_ONCE_INIT { PTHREAD_NEEDS_INIT, NULL }
/*
* Static initialization values.
*/
#define PTHREAD_MUTEX_INITIALIZER NULL
#define PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP NULL
#define PTHREAD_COND_INITIALIZER NULL
#define PTHREAD_RWLOCK_INITIALIZER NULL
/*
* Default attribute arguments (draft 4, deprecated).
*/
#ifndef PTHREAD_KERNEL
#define pthread_condattr_default NULL
#define pthread_mutexattr_default NULL
#define pthread_attr_default NULL
#endif
#define PTHREAD_PRIO_NONE 0
#define PTHREAD_PRIO_INHERIT 1
#define PTHREAD_PRIO_PROTECT 2
/*
* Mutex types (Single UNIX Specification, Version 2, 1997).
*
* Note that a mutex attribute with one of the following types:
*
* PTHREAD_MUTEX_NORMAL
* PTHREAD_MUTEX_RECURSIVE
*
* will deviate from POSIX specified semantics.
*/
enum pthread_mutextype {
PTHREAD_MUTEX_ERRORCHECK = 1, /* Default POSIX mutex */
PTHREAD_MUTEX_RECURSIVE = 2, /* Recursive mutex */
PTHREAD_MUTEX_NORMAL = 3, /* No error checking */
PTHREAD_MUTEX_ADAPTIVE_NP = 4, /* Adaptive mutex, spins briefly before blocking on lock */
PTHREAD_MUTEX_TYPE_MAX
};
#define PTHREAD_MUTEX_DEFAULT PTHREAD_MUTEX_ERRORCHECK
/*
* Thread function prototype definitions:
*/
__BEGIN_DECLS
int pthread_atfork(void (*)(void), void (*)(void), void (*)(void));
int pthread_attr_destroy(pthread_attr_t *);
int pthread_attr_getstack(const pthread_attr_t * __restrict,
void ** __restrict, size_t * __restrict);
int pthread_attr_getstacksize(const pthread_attr_t *, size_t *);
int pthread_attr_getguardsize(const pthread_attr_t *, size_t *);
int pthread_attr_getstackaddr(const pthread_attr_t *, void **);
int pthread_attr_getdetachstate(const pthread_attr_t *, int *);
int pthread_attr_init(pthread_attr_t *);
int pthread_attr_setstacksize(pthread_attr_t *, size_t);
int pthread_attr_setguardsize(pthread_attr_t *, size_t);
int pthread_attr_setstack(pthread_attr_t *, void *, size_t);
int pthread_attr_setstackaddr(pthread_attr_t *, void *);
int pthread_attr_setdetachstate(pthread_attr_t *, int);
int pthread_barrier_destroy(pthread_barrier_t *);
int pthread_barrier_init(pthread_barrier_t *,
const pthread_barrierattr_t *, unsigned);
int pthread_barrier_wait(pthread_barrier_t *);
int pthread_barrierattr_destroy(pthread_barrierattr_t *);
int pthread_barrierattr_getpshared(const pthread_barrierattr_t *,
int *);
int pthread_barrierattr_init(pthread_barrierattr_t *);
int pthread_barrierattr_setpshared(pthread_barrierattr_t *, int);
void pthread_cleanup_pop(int);
void pthread_cleanup_push(void (*) (void *), void *);
int pthread_condattr_destroy(pthread_condattr_t *);
int pthread_condattr_getclock(const pthread_condattr_t *,
clockid_t *);
int pthread_condattr_getpshared(const pthread_condattr_t *, int *);
int pthread_condattr_init(pthread_condattr_t *);
int pthread_condattr_setclock(pthread_condattr_t *, clockid_t);
int pthread_condattr_setpshared(pthread_condattr_t *, int);
int pthread_cond_broadcast(pthread_cond_t *);
int pthread_cond_destroy(pthread_cond_t *);
int pthread_cond_init(pthread_cond_t *,
const pthread_condattr_t *);
int pthread_cond_signal(pthread_cond_t *);
int pthread_cond_timedwait(pthread_cond_t *,
pthread_mutex_t *, const struct timespec *);
int pthread_cond_wait(pthread_cond_t *, pthread_mutex_t *);
int pthread_create(pthread_t *, const pthread_attr_t *,
void *(*) (void *), void *);
int pthread_detach(pthread_t);
int pthread_equal(pthread_t, pthread_t);
void pthread_exit(void *) __dead2;
void *pthread_getspecific(pthread_key_t);
int pthread_join(pthread_t, void **);
int pthread_key_create(pthread_key_t *,
void (*) (void *));
int pthread_key_delete(pthread_key_t);
int pthread_kill(pthread_t, int);
int pthread_mutexattr_init(pthread_mutexattr_t *);
int pthread_mutexattr_destroy(pthread_mutexattr_t *);
int pthread_mutexattr_getpshared(const pthread_mutexattr_t *,
int *);
int pthread_mutexattr_gettype(pthread_mutexattr_t *, int *);
int pthread_mutexattr_settype(pthread_mutexattr_t *, int);
int pthread_mutexattr_setpshared(pthread_mutexattr_t *, int);
int pthread_mutex_destroy(pthread_mutex_t *);
int pthread_mutex_init(pthread_mutex_t *,
const pthread_mutexattr_t *);
int pthread_mutex_lock(pthread_mutex_t *);
int pthread_mutex_trylock(pthread_mutex_t *);
int pthread_mutex_timedlock(pthread_mutex_t *,
const struct timespec *);
int pthread_mutex_unlock(pthread_mutex_t *);
int pthread_once(pthread_once_t *, void (*) (void));
int pthread_rwlock_destroy(pthread_rwlock_t *);
int pthread_rwlock_init(pthread_rwlock_t *,
const pthread_rwlockattr_t *);
int pthread_rwlock_rdlock(pthread_rwlock_t *);
int pthread_rwlock_timedrdlock(pthread_rwlock_t *,
const struct timespec *);
int pthread_rwlock_timedwrlock(pthread_rwlock_t *,
const struct timespec *);
int pthread_rwlock_tryrdlock(pthread_rwlock_t *);
int pthread_rwlock_trywrlock(pthread_rwlock_t *);
int pthread_rwlock_unlock(pthread_rwlock_t *);
int pthread_rwlock_wrlock(pthread_rwlock_t *);
int pthread_rwlockattr_init(pthread_rwlockattr_t *);
int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t *,
int *);
int pthread_rwlockattr_setpshared(pthread_rwlockattr_t *, int);
int pthread_rwlockattr_destroy(pthread_rwlockattr_t *);
pthread_t pthread_self(void);
int pthread_setspecific(pthread_key_t, const void *);
int pthread_sigmask(int, const __sigset_t *, __sigset_t *);
int pthread_spin_init(pthread_spinlock_t *, int);
int pthread_spin_destroy(pthread_spinlock_t *);
int pthread_spin_lock(pthread_spinlock_t *);
int pthread_spin_trylock(pthread_spinlock_t *);
int pthread_spin_unlock(pthread_spinlock_t *);
int pthread_cancel(pthread_t);
int pthread_setcancelstate(int, int *);
int pthread_setcanceltype(int, int *);
void pthread_testcancel(void);
int pthread_getprio(pthread_t);
int pthread_setprio(pthread_t, int);
void pthread_yield(void);
int pthread_mutexattr_getprioceiling(pthread_mutexattr_t *,
int *);
int pthread_mutexattr_setprioceiling(pthread_mutexattr_t *,
int);
int pthread_mutex_getprioceiling(pthread_mutex_t *, int *);
int pthread_mutex_setprioceiling(pthread_mutex_t *, int, int *);
int pthread_mutexattr_getprotocol(pthread_mutexattr_t *, int *);
int pthread_mutexattr_setprotocol(pthread_mutexattr_t *, int);
int pthread_attr_getinheritsched(const pthread_attr_t *, int *);
int pthread_attr_getschedparam(const pthread_attr_t *,
struct sched_param *);
int pthread_attr_getschedpolicy(const pthread_attr_t *, int *);
int pthread_attr_getscope(const pthread_attr_t *, int *);
int pthread_attr_setinheritsched(pthread_attr_t *, int);
int pthread_attr_setschedparam(pthread_attr_t *,
const struct sched_param *);
int pthread_attr_setschedpolicy(pthread_attr_t *, int);
int pthread_attr_setscope(pthread_attr_t *, int);
int pthread_getschedparam(pthread_t pthread, int *,
struct sched_param *);
int pthread_setschedparam(pthread_t, int,
const struct sched_param *);
int pthread_getconcurrency(void);
int pthread_setconcurrency(int);
__END_DECLS
#endif
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