You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
253 lines
8.1 KiB
253 lines
8.1 KiB
.\"
|
|
.\" Copyright 2013 Samy Al Bahra.
|
|
.\" 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.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
|
|
.\"
|
|
.\"
|
|
.Dd July 13, 2013.
|
|
.Dt ck_elide 3
|
|
.Sh NAME
|
|
.Nm CK_ELIDE_PROTOTYPE ,
|
|
.Nm CK_ELIDE_LOCK_ADAPTIVE ,
|
|
.Nm CK_ELIDE_UNLOCK_ADAPTIVE ,
|
|
.Nm CK_ELIDE_LOCK ,
|
|
.Nm CK_ELIDE_UNLOCK ,
|
|
.Nm CK_ELIDE_TRYLOCK_PROTOTYPE ,
|
|
.Nm CK_ELIDE_TRYLOCK
|
|
.Nd lock elision wrappers
|
|
.Sh LIBRARY
|
|
Concurrency Kit (libck, \-lck)
|
|
.Sh SYNOPSIS
|
|
.In ck_elide.h
|
|
.Pp
|
|
.Dv ck_elide_stat_t stat = CK_ELIDE_STAT_INITIALIZER;
|
|
.Pp
|
|
.Ft void
|
|
.Fn ck_elide_stat_init "ck_elide_stat_t *"
|
|
.Pp
|
|
.Dv struct ck_elide_config config = CK_ELIDE_CONFIG_DEFAULT_INITIALIZER;
|
|
.Pp
|
|
.Bd -literal -offset
|
|
struct ck_elide_config {
|
|
unsigned short skip_busy;
|
|
short retry_busy;
|
|
unsigned short skip_other;
|
|
short retry_other;
|
|
unsigned short skip_conflict;
|
|
short retry_conflict;
|
|
};
|
|
.Ed
|
|
.Pp
|
|
.Fn CK_ELIDE_PROTOTYPE "NAME" "TYPE" "LOCK_PREDICATE" "LOCK_FUNCTION" "UNLOCK_PREDICATE" "UNLOCK_FUNCTION"
|
|
.Fn CK_ELIDE_LOCK_ADAPTIVE "NAME" "ck_elide_stat_t *" "struct ck_elide_config *" "TYPE *"
|
|
.Fn CK_ELIDE_UNLOCK_ADAPTIVE "NAME" "ck_elide_stat_t *" "TYPE *"
|
|
.Fn CK_ELIDE_LOCK "NAME" "TYPE *"
|
|
.Fn CK_ELIDE_UNLOCK "NAME" "TYPE *"
|
|
.Fn CK_ELIDE_TRYLOCK_PROTOTYPE "NAME" "TYPE" "LOCK_PREDICATE" "TRYLOCK_FUNCTION"
|
|
.Sh DESCRIPTION
|
|
These macros implement lock elision wrappers for a user-specified single-argument
|
|
lock interface. The wrappers will attempt to elide lock acquisition, allowing
|
|
concurrent execution of critical sections that do not issue conflicting memory
|
|
operations. If any threads have successfully elided a lock acquisition,
|
|
conflicting memory operations will roll-back any side-effects of the critical
|
|
section and force every thread to retry the lock acquisition regularly.
|
|
.Pp
|
|
.Fn CK_ELIDE_LOCK ,
|
|
.Fn CK_ELIDE_UNLOCK ,
|
|
.Fn CK_ELIDE_LOCK_ADAPTIVE ,
|
|
and
|
|
.Fn CK_ELIDE_UNLOCK_ADAPTIVE
|
|
macros require
|
|
a previous
|
|
.Fn CK_ELIDE_PROTOTYPE
|
|
with the same
|
|
.Fa NAME .
|
|
Elision is attempted if the
|
|
.Fa LOCK_PREDICATE
|
|
function returns false. If
|
|
.Fa LOCK_PREDICATE
|
|
returns true then elision is aborted and
|
|
.Fa LOCK_FUNCTION
|
|
is executed instead. If any threads are in an elided critical section,
|
|
.Fa LOCK_FUNCTION
|
|
must force them to rollback through a conflicting memory operation.
|
|
The
|
|
.Fa UNLOCK_PREDICATE
|
|
function must return true if the lock is acquired by the caller, meaning
|
|
that the lock was not successfully elided. If
|
|
.Fa UNLOCK_PREDICATE
|
|
returns true, then the
|
|
.Fa UNLOCK_FUNCTION
|
|
is executed. If RTM is unsupported (no CK_F_PR_RTM macro) then
|
|
.Fn CK_ELIDE_LOCK
|
|
and
|
|
.Fn CK_ELIDE_LOCK_ADAPTIVE
|
|
will immediately call
|
|
.Fn LOCK_FUNCTION .
|
|
.Fn CK_ELIDE_UNLOCK
|
|
and
|
|
.Fn CK_ELIDE_UNLOCK_ADAPTIVE
|
|
will immediately call
|
|
.Fn UNLOCK_FUNCTION .
|
|
.Pp
|
|
.Fn CK_ELIDE_TRYLOCK
|
|
requires a previous
|
|
.Fn CK_ELIDE_TRYLOCK_PROTOTYPE
|
|
with the same name.
|
|
Elision is attempted if the
|
|
.Fa LOCK_PREDICATE
|
|
function returns false. If
|
|
.Fa LOCK_PREDICATE
|
|
returns true or if elision fails then the
|
|
operation is aborted. If RTM is unsupported
|
|
(no CK_F_PR_RTM macro) then
|
|
.Fn CK_ELIDE_TRYLOCK
|
|
will immediately call
|
|
.Fn TRYLOCK_FUNCTION .
|
|
.Pp
|
|
.Fn CK_ELIDE_LOCK_ADAPTIVE
|
|
and
|
|
.Fn CK_ELIDE_UNLOCK_ADAPTIVE
|
|
will adapt the elision behavior associated with lock operations
|
|
according to the run-time behavior of the program. This behavior
|
|
is defined by the ck_elide_config structure pointer passed to
|
|
.Fn CK_ELIDE_LOCK_ADAPTIVE .
|
|
A thread-local ck_elide_stat structure must be passed to both
|
|
.Fn CK_ELIDE_LOCK_ADAPTIVE
|
|
and
|
|
.Fn CK_ELIDE_UNLOCK_ADAPTIVE .
|
|
This structure is expected to be unique for different workloads,
|
|
may not be re-used in recursive acquisitions and must match the
|
|
lifetime of the lock it is associated with. It is safe to mix
|
|
adaptive calls with best-effort calls.
|
|
.Pp
|
|
Both ck_spinlock.h and ck_rwlock.h define ck_elide wrappers under
|
|
the ck_spinlock and ck_rwlock namespace, respectively.
|
|
.Sh EXAMPLES
|
|
This example utilizes built-in lock elision facilities in ck_rwlock and ck_spinlock.
|
|
.Bd -literal -offset indent
|
|
#include <ck_rwlock.h>
|
|
#include <ck_spinlock.h>
|
|
|
|
static ck_rwlock_t rw = CK_RWLOCK_INITIALIZER;
|
|
static struct ck_elide_config rw_config =
|
|
CK_ELIDE_CONFIG_DEFAULT_INITIALIZER;
|
|
static __thread ck_elide_stat_t rw_stat =
|
|
CK_ELIDE_STAT_INITIALIZER;
|
|
|
|
static ck_spinlock_t spinlock = CK_SPINLOCK_INITIALIZER;
|
|
static struct ck_elide_config spinlock_config =
|
|
CK_ELIDE_CONFIG_DEFAULT_INITIALIZER;
|
|
static __thread ck_elide_stat_t spinlock_stat =
|
|
CK_ELIDE_STAT_INITIALIZER;
|
|
|
|
void
|
|
function(void)
|
|
{
|
|
|
|
/* Lock-unlock write-side lock in weak best-effort manner. */
|
|
CK_ELIDE_LOCK(ck_rwlock_write, &rw);
|
|
CK_ELIDE_UNLOCK(ck_rwlock_write, &rw);
|
|
|
|
/* Attempt to acquire the write-side lock. */
|
|
if (CK_ELIDE_TRYLOCK(ck_rwlock_write, &rw) == true)
|
|
CK_ELIDE_UNLOCK(ck_rwlock_write, &rw);
|
|
|
|
/* Lock-unlock read-side lock in weak best-effort manner. */
|
|
CK_ELIDE_LOCK(ck_rwlock_read, &rw);
|
|
CK_ELIDE_UNLOCK(ck_rwlock_read, &rw);
|
|
|
|
/* Attempt to acquire the read-side lock. */
|
|
if (CK_ELIDE_TRYLOCK(ck_rwlock_read, &rw) == true)
|
|
CK_ELIDE_UNLOCK(ck_rwlock_read, &rw);
|
|
|
|
/* Lock-unlock write-side lock in an adaptive manner. */
|
|
CK_ELIDE_LOCK_ADAPTIVE(ck_rwlock_write, &rw_stat,
|
|
&rw_config, &rw);
|
|
CK_ELIDE_UNLOCK_ADAPTIVE(ck_rwlock_write, &rw_stat,
|
|
&rw_config, &rw);
|
|
|
|
/* Lock-unlock read-side lock in an adaptive manner. */
|
|
CK_ELIDE_LOCK_ADAPTIVE(ck_rwlock_read, &rw_stat,
|
|
&rw_config, &rw);
|
|
CK_ELIDE_UNLOCK_ADAPTIVE(ck_rwlock_read, &rw_stat,
|
|
&rw_config, &rw);
|
|
|
|
/* Lock-unlock spinlock in weak best-effort manner. */
|
|
CK_ELIDE_LOCK(ck_spinlock, &spinlock);
|
|
CK_ELIDE_UNLOCK(ck_spinlock, &spinlock);
|
|
|
|
/* Attempt to acquire the lock. */
|
|
if (CK_ELIDE_TRYLOCK(ck_spinlock, &lock) == true)
|
|
CK_ELIDE_UNLOCK(ck_spinlock, &spinlock);
|
|
|
|
/* Lock-unlock spinlock in an adaptive manner. */
|
|
CK_ELIDE_LOCK_ADAPTIVE(ck_spinlock, &spinlock_stat,
|
|
&spinlock_config, &spinlock);
|
|
CK_ELIDE_UNLOCK_ADAPTIVE(ck_spinlock, &spinlock_stat,
|
|
&spinlock_config, &spinlock);
|
|
}
|
|
.Ed
|
|
.Pp
|
|
In this example, user-defined locking functions are provided an elision
|
|
implementation.
|
|
.Bd -literal -offset indent
|
|
/* Assume lock_t has been previously defined. */
|
|
#include <ck_elide.h>
|
|
|
|
/*
|
|
* This function returns true if the lock is unavailable at the time
|
|
* it was called or false if the lock is available.
|
|
*/
|
|
bool is_locked(lock_t *);
|
|
|
|
/*
|
|
* This function acquires the supplied lock.
|
|
*/
|
|
void lock(lock_t *);
|
|
|
|
/*
|
|
* This function releases the lock.
|
|
*/
|
|
void unlock(lock_t *);
|
|
|
|
CK_ELIDE_PROTOTYPE(my_lock, lock_t, is_locked, lock, is_locked, unlock)
|
|
|
|
static lock_t lock;
|
|
|
|
void
|
|
function(void)
|
|
{
|
|
|
|
CK_ELIDE_LOCK(my_lock, &lock);
|
|
CK_ELIDE_UNLOCK(my_lock, &lock);
|
|
}
|
|
.Ed
|
|
.Sh SEE ALSO
|
|
.Xr ck_rwlock 3 ,
|
|
.Xr ck_spinlock 3
|
|
.Pp
|
|
Ravi Rajwar and James R. Goodman. 2001. Speculative lock elision: enabling highly concurrent multithreaded execution. In Proceedings of the 34th annual ACM/IEEE international symposium on Microarchitecture (MICRO 34). IEEE Computer Society, Washington, DC, USA, 294-305.
|
|
.Pp
|
|
Additional information available at http://en.wikipedia.org/wiki/Transactional_Synchronization_Extensions and http://concurrencykit.org/
|