database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-29 05:21:33 +03:00
Code Activity

Fast mutexes implementation

Browse Source 
(spin-loop inside pthread_mutex_lock).

thr_mutex.c:
  Added spinloop in mutex_lock
my_pthread.h:
  Added definition of my_pthread_fastmutex_t
configure.in:
  Added --with-fast-mutexes switch


configure.in:
  Added --with-fast-mutexes switch
include/my_pthread.h:
  Added definition of my_pthread_fastmutex_t
mysys/thr_mutex.c:
  Added spinloop in mutex_lock
This commit is contained in:
unknown
2005-12-20 14:56:45 +01:00
parent a62aaaef7a
commit 59b4604611
3 changed files with 122 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

77
mysys/thr_mutex.c
View File

@ -356,3 +356,80 @@ void safe_mutex_end(FILE *file __attribute__((unused)))
}
#endif /* THREAD && SAFE_MUTEX */
#if defined(THREAD) && defined(MY_PTHREAD_FASTMUTEX) && !defined(SAFE_MUTEX)
#include "mysys_priv.h"
#include "my_static.h"
#include <m_string.h>
#include <m_ctype.h>
#include <hash.h>
#include <myisampack.h>
#include <mysys_err.h>
#include <my_sys.h>
#undef pthread_mutex_t
#undef pthread_mutex_init
#undef pthread_mutex_lock
#undef pthread_mutex_trylock
#undef pthread_mutex_unlock
#undef pthread_mutex_destroy
#undef pthread_cond_wait
#undef pthread_cond_timedwait
ulong mutex_delay(ulong delayloops)
{
ulong i;
volatile ulong j;
j = 0;
for (i = 0; i < delayloops * 50; i++)
j += i;
return(j);
}
#define MY_PTHREAD_FASTMUTEX_SPINS 8
#define MY_PTHREAD_FASTMUTEX_DELAY 4
int my_pthread_fastmutex_init(my_pthread_fastmutex_t *mp,
const pthread_mutexattr_t *attr)
{
static int cpu_count= 0;
#ifdef _SC_NPROCESSORS_CONF
if (!cpu_count && (attr == MY_MUTEX_INIT_FAST))
cpu_count= sysconf(_SC_NPROCESSORS_CONF);
#endif
if ((cpu_count > 1) && (attr == MY_MUTEX_INIT_FAST))
mp->spins= MY_PTHREAD_FASTMUTEX_SPINS;
else
mp->spins= 0;
return pthread_mutex_init(&mp->mutex, attr);
}
int my_pthread_fastmutex_lock(my_pthread_fastmutex_t *mp)
{
int res;
uint i;
uint maxdelay= MY_PTHREAD_FASTMUTEX_DELAY;
for (i= 0; i < mp->spins; i++)
{
res= pthread_mutex_trylock(&mp->mutex);
if (res == 0)
return 0;
if (res != EBUSY)
return res;
mutex_delay(maxdelay);
maxdelay += ((double) random() / (double) RAND_MAX) *
MY_PTHREAD_FASTMUTEX_DELAY + 1;
}
return pthread_mutex_lock(&mp->mutex);
}
#endif /* defined(THREAD) && defined(MY_PTHREAD_FASTMUTEX) && !defined(SAFE_MUTEX) */