ck_brlock(3) | Library Functions Manual | ck_brlock(3) |
NAME
ck_brlock_init
,
ck_brlock_write_lock
,
ck_brlock_write_unlock
,
ck_brlock_write_trylock
,
ck_brlock_read_register
,
ck_brlock_read_unregister
,
ck_brlock_read_lock
,
ck_brlock_read_trylock
,
ck_brlock_read_unlock
—
big-reader locks
LIBRARY
Concurrency Kit (libck, -lck)
SYNOPSIS
#include
<ck_brlock.h>
ck_brlock_t brlock =
CK_BRLOCK_INITIALIZER;
ck_brlock_reader_t reader =
CK_BRLOCK_READER_INITIALIZER;
void
ck_brlock_init
(ck_brlock_t
*br);
void
ck_brlock_write_lock
(ck_brlock_t
*br);
void
ck_brlock_write_unlock
(ck_brlock_t
*br);
bool
ck_brlock_write_trylock
(ck_brlock_t
*br, unsigned int
factor);
void
ck_brlock_read_register
(ck_brlock_t
*br, ck_brlock_reader_t
*reader);
void
ck_brlock_read_unregister
(ck_brlock_t
*br, ck_brlock_reader_t
*reader);
void
ck_brlock_read_lock
(ck_brlock_t
*br, ck_brlock_reader_t
*reader);
bool
ck_brlock_read_trylock
(ck_brlock_t
*br, ck_brlock_reader_t
*reader, unsigned int
factor);
void
ck_brlock_read_unlock
(ck_brlock_reader_t
*reader);
DESCRIPTION
Big reader locks are distributed reader-writer locks with low latency constant time reader acquisition (with respect to number of concurrent readers). On the other hand, writer acquisitions are a relatively expensive O(n) operation. This is a write-biased lock.
EXAMPLE
static ck_brlock_t lock = CK_BRLOCK_INITIALIZER; static __thread ck_brlock_reader_t reader; static void reader(void) { /* Add our thread as a lock participant. */ ck_brlock_read_register(&lock, &reader); for (;;) { ck_brlock_read_lock(&lock, &reader); /* Read-side critical section. */ ck_brlock_read_unlock(&reader); if (ck_brlock_read_trylock(&lock, &reader, 1) == true) { /* Read-side critical section. */ ck_brlock_read_unlock(&reader); } } return; } static void writer(void) { for (;;) { ck_brlock_write_lock(&lock); /* Write-side critical section. */ ck_brlock_write_unlock(&lock); if (ck_brlock_write_trylock(&lock, 1) == true) { /* Write-side critical section. */ ck_brlock_write_unlock(&lock); } } return; }
SEE ALSO
Additional information available at http://concurrencykit.org/
July 26, 2013. |