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MDEV-8111 - remove "fast mutexes"
They aren't faster than normal mutexes. They're disabled by default for years, so de facto it's dead code, never used.
This commit is contained in:
Sergey Vojtovich
parent
e4212898a6
commit
e562b43222
5 changed files with 0 additions and 131 deletions
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@ -224,9 +224,6 @@ MY_CHECK_AND_SET_COMPILER_FLAG(-ggdb3 DEBUG)
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OPTION(ENABLED_LOCAL_INFILE
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"If we should should enable LOAD DATA LOCAL by default" ${IF_WIN})
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OPTION(WITH_FAST_MUTEXES "Compile with fast mutexes" OFF)
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MARK_AS_ADVANCED(WITH_FAST_MUTEXES)
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OPTION(WITH_INNODB_DISALLOW_WRITES "InnoDB freeze writes patch from Google" ${WITH_WSREP})
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IF (WITH_INNODB_DISALLOW_WRITES)
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SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -DWITH_INNODB_DISALLOW_WRITES")
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@ -241,10 +238,6 @@ FOREACH(BUILD_TYPE RELEASE RELWITHDEBINFO MINSIZEREL)
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SET(CMAKE_${LANG}_FLAGS_${BUILD_TYPE}
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"${CMAKE_${LANG}_FLAGS_${BUILD_TYPE}} -DDBUG_OFF")
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ENDIF()
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IF(WITH_FAST_MUTEXES)
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SET(CMAKE_${LANG}_FLAGS_${BUILD_TYPE}
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"${CMAKE_${LANG}_FLAGS_${BUILD_TYPE}} -DMY_PTHREAD_FASTMUTEX=1")
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ENDIF()
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ENDFOREACH()
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ENDFOREACH()
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@ -445,30 +445,10 @@ void safe_mutex_free_deadlock_data(safe_mutex_t *mp);
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#define safe_mutex_assert_not_owner(mp) do {} while (0)
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#define safe_mutex_setflags(mp, F) do {} while (0)
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#if defined(MY_PTHREAD_FASTMUTEX)
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#define my_cond_timedwait(A,B,C) pthread_cond_timedwait((A), &(B)->mutex, (C))
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#define my_cond_wait(A,B) pthread_cond_wait((A), &(B)->mutex)
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#else
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#define my_cond_timedwait(A,B,C) pthread_cond_timedwait((A),(B),(C))
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#define my_cond_wait(A,B) pthread_cond_wait((A), (B))
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#endif /* MY_PTHREAD_FASTMUTEX */
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#endif /* !SAFE_MUTEX */
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#if defined(MY_PTHREAD_FASTMUTEX) && !defined(SAFE_MUTEX)
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typedef struct st_my_pthread_fastmutex_t
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{
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pthread_mutex_t mutex;
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uint spins;
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uint rng_state;
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} my_pthread_fastmutex_t;
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void fastmutex_global_init(void);
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int my_pthread_fastmutex_init(my_pthread_fastmutex_t *mp,
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const pthread_mutexattr_t *attr);
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int my_pthread_fastmutex_lock(my_pthread_fastmutex_t *mp);
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#endif /* defined(MY_PTHREAD_FASTMUTEX) && !defined(SAFE_MUTEX) */
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/* READ-WRITE thread locking */
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#if defined(USE_MUTEX_INSTEAD_OF_RW_LOCKS)
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@ -71,8 +71,6 @@ struct st_mysql_mutex
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/** The real mutex. */
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#ifdef SAFE_MUTEX
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safe_mutex_t m_mutex;
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#elif defined(MY_PTHREAD_FASTMUTEX)
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my_pthread_fastmutex_t m_mutex;
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#else
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pthread_mutex_t m_mutex;
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#endif
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@ -619,8 +617,6 @@ static inline int inline_mysql_mutex_init(
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#endif
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#ifdef SAFE_MUTEX
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return safe_mutex_init(&that->m_mutex, attr, src_name, src_file, src_line);
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#elif defined(MY_PTHREAD_FASTMUTEX)
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return my_pthread_fastmutex_init(&that->m_mutex, attr);
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#else
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return pthread_mutex_init(&that->m_mutex, attr);
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#endif
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@ -642,8 +638,6 @@ static inline int inline_mysql_mutex_destroy(
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#endif
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#ifdef SAFE_MUTEX
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return safe_mutex_destroy(&that->m_mutex, src_file, src_line);
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#elif defined(MY_PTHREAD_FASTMUTEX)
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return pthread_mutex_destroy(&that->m_mutex.mutex);
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#else
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return pthread_mutex_destroy(&that->m_mutex);
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#endif
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@ -670,8 +664,6 @@ static inline int inline_mysql_mutex_lock(
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/* Instrumented code */
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#ifdef SAFE_MUTEX
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result= safe_mutex_lock(&that->m_mutex, FALSE, src_file, src_line);
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#elif defined(MY_PTHREAD_FASTMUTEX)
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result= my_pthread_fastmutex_lock(&that->m_mutex);
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#else
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result= pthread_mutex_lock(&that->m_mutex);
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#endif
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@ -687,8 +679,6 @@ static inline int inline_mysql_mutex_lock(
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/* Non instrumented code */
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#ifdef SAFE_MUTEX
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result= safe_mutex_lock(&that->m_mutex, FALSE, src_file, src_line);
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#elif defined(MY_PTHREAD_FASTMUTEX)
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result= my_pthread_fastmutex_lock(&that->m_mutex);
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#else
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result= pthread_mutex_lock(&that->m_mutex);
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#endif
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@ -717,8 +707,6 @@ static inline int inline_mysql_mutex_trylock(
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/* Instrumented code */
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#ifdef SAFE_MUTEX
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result= safe_mutex_lock(&that->m_mutex, TRUE, src_file, src_line);
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#elif defined(MY_PTHREAD_FASTMUTEX)
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result= pthread_mutex_trylock(&that->m_mutex.mutex);
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#else
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result= pthread_mutex_trylock(&that->m_mutex);
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#endif
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@ -734,8 +722,6 @@ static inline int inline_mysql_mutex_trylock(
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/* Non instrumented code */
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#ifdef SAFE_MUTEX
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result= safe_mutex_lock(&that->m_mutex, TRUE, src_file, src_line);
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#elif defined(MY_PTHREAD_FASTMUTEX)
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result= pthread_mutex_trylock(&that->m_mutex.mutex);
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#else
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result= pthread_mutex_trylock(&that->m_mutex);
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#endif
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@ -759,8 +745,6 @@ static inline int inline_mysql_mutex_unlock(
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#ifdef SAFE_MUTEX
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result= safe_mutex_unlock(&that->m_mutex, src_file, src_line);
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#elif defined(MY_PTHREAD_FASTMUTEX)
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result= pthread_mutex_unlock(&that->m_mutex.mutex);
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#else
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result= pthread_mutex_unlock(&that->m_mutex);
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#endif
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@ -105,8 +105,6 @@ void my_mutex_init()
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#if defined(SAFE_MUTEX_DEFINED)
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safe_mutex_global_init();
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#elif defined(MY_PTHREAD_FASTMUTEX)
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fastmutex_global_init();
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#endif
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}
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@ -838,88 +836,4 @@ static void print_deadlock_warning(safe_mutex_t *new_mutex,
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DBUG_VOID_RETURN;
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}
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#elif defined(MY_PTHREAD_FASTMUTEX) /* !SAFE_MUTEX_DEFINED */
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static ulong mutex_delay(ulong delayloops)
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{
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ulong i;
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volatile ulong j;
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j = 0;
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for (i = 0; i < delayloops * 50; i++)
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j += i;
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return(j);
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}
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#define MY_PTHREAD_FASTMUTEX_SPINS 8
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#define MY_PTHREAD_FASTMUTEX_DELAY 4
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static int cpu_count= 0;
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int my_pthread_fastmutex_init(my_pthread_fastmutex_t *mp,
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const pthread_mutexattr_t *attr)
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{
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if ((cpu_count > 1) && (attr == MY_MUTEX_INIT_FAST))
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mp->spins= MY_PTHREAD_FASTMUTEX_SPINS;
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else
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mp->spins= 0;
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mp->rng_state= 1;
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return pthread_mutex_init(&mp->mutex, attr);
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}
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/**
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Park-Miller random number generator. A simple linear congruential
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generator that operates in multiplicative group of integers modulo n.
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x_{k+1} = (x_k g) mod n
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Popular pair of parameters: n = 2^32 − 5 = 4294967291 and g = 279470273.
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The period of the generator is about 2^31.
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Largest value that can be returned: 2147483646 (RAND_MAX)
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Reference:
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S. K. Park and K. W. Miller
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"Random number generators: good ones are hard to find"
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Commun. ACM, October 1988, Volume 31, No 10, pages 1192-1201.
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*/
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static double park_rng(my_pthread_fastmutex_t *mp)
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{
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mp->rng_state= ((my_ulonglong)mp->rng_state * 279470273U) % 4294967291U;
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return (mp->rng_state / 2147483647.0);
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}
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int my_pthread_fastmutex_lock(my_pthread_fastmutex_t *mp)
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{
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int res;
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uint i;
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uint maxdelay= MY_PTHREAD_FASTMUTEX_DELAY;
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for (i= 0; i < mp->spins; i++)
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{
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res= pthread_mutex_trylock(&mp->mutex);
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if (res == 0)
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return 0;
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if (res != EBUSY)
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return res;
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mutex_delay(maxdelay);
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maxdelay += park_rng(mp) * MY_PTHREAD_FASTMUTEX_DELAY + 1;
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}
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return pthread_mutex_lock(&mp->mutex);
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}
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void fastmutex_global_init(void)
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{
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#ifdef _SC_NPROCESSORS_CONF
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cpu_count= sysconf(_SC_NPROCESSORS_CONF);
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#endif
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}
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#endif /* defined(MY_PTHREAD_FASTMUTEX) && defined(SAFE_MUTEX_DEFINED) */
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@ -140,8 +140,6 @@ static int my_strnncoll_binary(CHARSET_INFO * cs __attribute__((unused)),
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/* How to access the pthread_mutex in mysql_mutex_t */
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#ifdef SAFE_MUTEX
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#define mysql_mutex_real_mutex(A) &(A)->m_mutex.mutex
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#elif defined(MY_PTHREAD_FASTMUTEX)
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#define mysql_mutex_real_mutex(A) &(A)->m_mutex.mutex
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#else
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#define mysql_mutex_real_mutex(A) &(A)->m_mutex
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#endif
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