diff options
Diffstat (limited to 'erts/emulator/beam/erl_lock_count.h')
| -rw-r--r-- | erts/emulator/beam/erl_lock_count.h | 937 |
1 files changed, 815 insertions, 122 deletions
diff --git a/erts/emulator/beam/erl_lock_count.h b/erts/emulator/beam/erl_lock_count.h index 6caffbfe86..c89dfcba47 100644 --- a/erts/emulator/beam/erl_lock_count.h +++ b/erts/emulator/beam/erl_lock_count.h @@ -18,60 +18,56 @@ * %CopyrightEnd% */ -/* - * Description: Statistics for locks. - * - * Author: Björn-Egil Dahlberg - * Date: 2008-07-03 - * Abstract: - * Locks statistics internal representation. - * - * Conceptual representation, - * - set name - * | - id (the unique lock) - * | | - lock type - * | | - statistics - * | | | - location (file and line number) - * | | | - tries - * | | | - collisions (including trylock busy) - * | | | - timer (time spent in waiting for lock) - * | | | - n_timer (collisions excluding trylock busy) - * | | | - histogram - * | | | | - # 0 = log2(lock wait_time ns) - * | | | | - ... - * | | | | - # n = log2(lock wait_time ns) - * - * Each instance of a lock is the unique lock, i.e. set and id in that set. - * For each lock there is a set of statistics with where and what impact - * the lock aqusition had. - * - * Runtime options - * - suspend, used when internal lock-counting can't be applied. For instance - * when allocating a term for the outside and halloc needs to be used. - * Default: off. - * - location, reserved and not used. - * - proclock, disable proclock counting. Used when performance might be an - * issue. Accessible from erts_debug:lock_counters({process_locks, bool()}). - * Default: off. - * - copysave, enable saving of destroyed locks (and thereby its statistics). - * If memory constraints is an issue this need to be disabled. - * Accessible from erts_debug:lock_counters({copy_save, bool()}). - * Default: off. +/** + * @description Statistics for locks. + * @file erl_lock_count.h + * + * @author Björn-Egil Dahlberg + * @author John Högberg + * + * Conceptual representation: * + * - set name + * | - id (the unique lock) + * | | - lock type + * | | - statistics + * | | | - location (file and line number) + * | | | - attempts + * | | | - collisions (including trylock busy) + * | | | - timer (time spent in waiting for lock) + * | | | - n_timer (collisions excluding trylock busy) + * | | | - histogram + * | | | | - # 0 = log2(lock wait_time ns) + * | | | | - ... + * | | | | - # n = log2(lock wait_time ns) + * + * Each instance of a lock is the unique lock, i.e. set and id in that set. + * For each lock there is a set of statistics with where and what impact + * the lock aqusition had. + * + * Runtime options: + * - location, reserved and not used. + * - proclock, disable proclock counting. Used when performance might be an + * issue. Accessible from erts_debug:lock_counters({process_locks, bool()}). + * Default: off. + * - copysave, enable saving of destroyed locks (and thereby its statistics). + * If memory constraints is an issue this need to be disabled. + * Accessible from erts_debug:lock_counters({copy_save, bool()}). + * Default: off. */ -#include "sys.h" - #ifndef ERTS_LOCK_COUNT_H__ #define ERTS_LOCK_COUNT_H__ #ifdef ERTS_ENABLE_LOCK_COUNT #ifndef ERTS_ENABLE_LOCK_POSITION -/* Enable in order for _x variants of mtx functions to be used. */ +/** @brief Controls whether _x variants of mtx functions are used. */ #define ERTS_ENABLE_LOCK_POSITION 1 #endif +#include "sys.h" #include "ethread.h" +#include "erl_term.h" #define ERTS_LCNT_MAX_LOCK_LOCATIONS (10) @@ -106,13 +102,8 @@ | ERTS_LCNT_LT_RWMUTEX \ | ERTS_LCNT_LT_PROCLOCK ) -#define ERTS_LCNT_LOCK_TYPE(lock) ((lock)->flag & ERTS_LCNT_LT_ALL) -#define ERTS_LCNT_IS_LOCK_INVALID(lock) (!((lock)->flag & ERTS_LCNT_LT_ALL)) -#define ERTS_LCNT_CLEAR_FLAG(lock) ((lock)->flag = 0) - -/* runtime options */ +/* Runtime options */ -#define ERTS_LCNT_OPT_SUSPEND (((Uint16) 1) << 0) #define ERTS_LCNT_OPT_LOCATION (((Uint16) 1) << 1) #define ERTS_LCNT_OPT_PROCLOCK (((Uint16) 1) << 2) #define ERTS_LCNT_OPT_PORTLOCK (((Uint16) 1) << 3) @@ -123,116 +114,818 @@ typedef struct { unsigned long ns; } erts_lcnt_time_t; -extern erts_lcnt_time_t timer_start; - typedef struct { - Uint32 ns[ERTS_LCNT_HISTOGRAM_SLOT_SIZE]; /* log2 array of nano seconds occurences */ + /* @brief log2 array of nano seconds occurences */ + Uint32 ns[ERTS_LCNT_HISTOGRAM_SLOT_SIZE]; } erts_lcnt_hist_t; -typedef struct erts_lcnt_lock_stats_s { - /* "tries" and "colls" needs to be atomic since - * trylock busy does not acquire a lock and there - * is no post action to rectify the situation - */ +typedef struct { + /** @brief In which file the lock was taken. May be NULL. */ + const char *file; + /** @brief Line number in \c file */ + unsigned int line; + + /* "attempts" and "collisions" need to be atomic since try_lock busy does + * not acquire a lock and there is no post action to rectify the + * situation. */ - char *file; /* which file the lock was taken */ - unsigned int line; /* line number in file */ + ethr_atomic_t attempts; + ethr_atomic_t collisions; - ethr_atomic_t tries; /* n tries to get lock */ - ethr_atomic_t colls; /* n collisions of tries to get lock */ + erts_lcnt_time_t total_time_waited; + Uint64 times_waited; - unsigned long timer_n; /* #times waited for lock */ - erts_lcnt_time_t timer; /* total wait time for lock */ - erts_lcnt_hist_t hist; + erts_lcnt_hist_t wait_time_histogram; } erts_lcnt_lock_stats_t; -/* rw locks uses both states, other locks only uses w_state */ -typedef struct erts_lcnt_lock_s { - char *name; /* lock name */ - Uint16 flag; /* lock type */ - Eterm id; /* id if possible */ +typedef struct lcnt_lock_info_t_ { + const char *name; /**< Lock name */ + Uint16 flag; /**< Lock type */ + Eterm id; /**< Id if possible, must be an immediate */ -#ifdef DEBUG + /* The first entry is reserved as a fallback for when location information + * is missing, and when the lock is used in more than (MAX_LOCK_LOCATIONS + * - 1) different places. */ + erts_lcnt_lock_stats_t location_stats[ERTS_LCNT_MAX_LOCK_LOCATIONS]; + unsigned int location_count; + + /* -- Everything below is internal to this module ---------------------- */ + + /* Lock states; rw locks uses both states, other locks only uses w_state */ + + /** @brief Write state. 0 = not taken, otherwise n threads waiting */ + ethr_atomic_t w_state; + /** @brief Read state. 0 = not taken, > 0 -> writes will wait */ + ethr_atomic_t r_state; + +#ifdef LCNT_DEBUG_LOCK_FLOW + /** @brief Tracks lock/unlock operations. This will explode if the lock is + * held at the time lock counting is installed. + * + * Avoid enabling existing locks at runtime while running in this + * configuration. */ ethr_atomic_t flowstate; #endif - /* lock states */ - ethr_atomic_t w_state; /* 0 not taken, otherwise n threads waiting */ - ethr_atomic_t r_state; /* 0 not taken, > 0 -> writes will wait */ + struct lcnt_lock_info_t_ *prev; + struct lcnt_lock_info_t_ *next; - /* statistics */ - unsigned int n_stats; - erts_lcnt_lock_stats_t stats[ERTS_LCNT_MAX_LOCK_LOCATIONS]; /* first entry is "undefined"*/ + /** @brief Used in place of erts_refc_t to avoid a circular dependency. */ + ethr_atomic_t ref_count; + ethr_atomic32_t lock; - /* chains for list handling */ - /* data is hold by lcnt_lock */ - struct erts_lcnt_lock_s *prev; - struct erts_lcnt_lock_s *next; -} erts_lcnt_lock_t; + /** @brief Deletion hook called once \c ref_count reaches 0; may defer + * deletion by modifying \c ref_count. */ + void (*dispose)(struct lcnt_lock_info_t_ *); -typedef struct { - erts_lcnt_lock_t *head; - erts_lcnt_lock_t *tail; - unsigned long n; -} erts_lcnt_lock_list_t; + struct lcnt_lock_info_carrier_ *carrier; +} erts_lcnt_lock_info_t; + +typedef struct lcnt_lock_info_list_ { + erts_lcnt_lock_info_t head; + erts_lcnt_lock_info_t tail; +} erts_lcnt_lock_info_list_t; typedef struct { - erts_lcnt_time_t duration; /* time since last clear */ - erts_lcnt_lock_list_t *current_locks; - erts_lcnt_lock_list_t *deleted_locks; + erts_lcnt_time_t timer_start; /**< Time of last clear */ + erts_lcnt_time_t duration; /**< Time since last clear */ + + erts_lcnt_lock_info_list_t *current_locks; + erts_lcnt_lock_info_list_t *deleted_locks; } erts_lcnt_data_t; -typedef struct { - int id; +typedef struct lcnt_lock_info_carrier_ erts_lcnt_lock_info_carrier_t; - erts_lcnt_time_t timer; /* timer */ - int timer_set; /* bool */ - int lock_in_conflict; /* bool */ -} erts_lcnt_thread_data_t; +typedef ethr_atomic_t erts_lcnt_ref_t; -/* globals */ +/* -- Globals -------------------------------------------------------------- */ extern Uint16 erts_lcnt_rt_options; -/* function declerations */ - -void erts_lcnt_init(void); +/* -- Lock operations ------------------------------------------------------ + * + * All of these will nop if there's nothing "installed" on the given reference, + * in order to transparently support enable/disable at runtime. */ + +/** @brief Records that a lock is being acquired. */ +ERTS_GLB_FORCE_INLINE +void erts_lcnt_lock(erts_lcnt_ref_t *ref); + +/** @copydoc erts_lcnt_lock + * @param option Notes whether the lock is a read or write lock. */ +ERTS_GLB_FORCE_INLINE +void erts_lcnt_lock_opt(erts_lcnt_ref_t *ref, Uint16 option); + +/** @brief Records that a lock has been acquired. */ +ERTS_GLB_FORCE_INLINE +void erts_lcnt_lock_post(erts_lcnt_ref_t *ref); + +/** @copydoc erts_lcnt_lock_post. + * @param file The name of the file where the lock was acquired. + * @param line The line at which the lock was acquired. */ +ERTS_GLB_FORCE_INLINE +void erts_lcnt_lock_post_x(erts_lcnt_ref_t *ref, char *file, unsigned int line); + +/** @brief Records that a lock has been released. */ +ERTS_GLB_FORCE_INLINE +void erts_lcnt_unlock(erts_lcnt_ref_t *ref); + +/** @copydoc erts_lcnt_unlock_opt + * @param option Whether the lock is a read or write lock. */ +ERTS_GLB_FORCE_INLINE +void erts_lcnt_unlock_opt(erts_lcnt_ref_t *ref, Uint16 option); + +/** @brief Rectifies the case where a lock wasn't actually a lock operation. + * + * Only used for process locks at the moment. */ +ERTS_GLB_FORCE_INLINE +void erts_lcnt_lock_unacquire(erts_lcnt_ref_t *ref); + +/** @brief Records the result of a trylock, placing the queried lock status in + * \c result. */ +ERTS_GLB_FORCE_INLINE +void erts_lcnt_trylock(erts_lcnt_ref_t *ref, int result); + +/** @copydoc erts_lcnt_trylock + * @param option Whether the lock is a read or write lock. */ +ERTS_GLB_FORCE_INLINE +void erts_lcnt_trylock_opt(erts_lcnt_ref_t *ref, int result, Uint16 option); + +/* Indexed variants of the standard lock operations, for use when a single + * reference contains many counters (eg. process locks). + * + * erts_lcnt_open_ref must be used to safely extract the installed carrier, + * which must released with erts_lcnt_close_reference on success. + * + * Refer to \c erts_lcnt_lock for example usage. */ + +ERTS_GLB_FORCE_INLINE +int erts_lcnt_open_ref(erts_lcnt_ref_t *ref, int *handle, erts_lcnt_lock_info_carrier_t **result); + +ERTS_GLB_FORCE_INLINE +void erts_lcnt_close_ref(int handle, erts_lcnt_lock_info_carrier_t *carrier); + +ERTS_GLB_INLINE +void erts_lcnt_lock_idx(erts_lcnt_lock_info_carrier_t *carrier, int index); +ERTS_GLB_INLINE +void erts_lcnt_lock_opt_idx(erts_lcnt_lock_info_carrier_t *carrier, int index, Uint16 option); + +ERTS_GLB_INLINE +void erts_lcnt_lock_post_idx(erts_lcnt_lock_info_carrier_t *carrier, int index); +ERTS_GLB_INLINE +void erts_lcnt_lock_post_x_idx(erts_lcnt_lock_info_carrier_t *carrier, int index, char *file, unsigned int line); + +ERTS_GLB_INLINE +void erts_lcnt_lock_unacquire_idx(erts_lcnt_lock_info_carrier_t *carrier, int index); + +ERTS_GLB_INLINE +void erts_lcnt_unlock_idx(erts_lcnt_lock_info_carrier_t *carrier, int index); +ERTS_GLB_INLINE +void erts_lcnt_unlock_opt_idx(erts_lcnt_lock_info_carrier_t *carrier, int index, Uint16 option); + +ERTS_GLB_INLINE +void erts_lcnt_trylock_idx(erts_lcnt_lock_info_carrier_t *carrier, int index, int result); +ERTS_GLB_INLINE +void erts_lcnt_trylock_opt_idx(erts_lcnt_lock_info_carrier_t *carrier, int index, int result, Uint16 option); + +/* -- Reference operations ------------------------------------------------- */ + +erts_lcnt_lock_info_carrier_t *erts_lcnt_create_lock_info_carrier(int count); + +/** @brief Fills in the name and lock type of the given index. */ +#define erts_lcnt_init_lock_info_idx(carrier, index, name, flag) \ + erts_lcnt_init_lock_info_x_idx(carrier, index, name, flag, NIL) + +/** @copydoc erts_lcnt_install_new_lock_info + * @param id An immediate erlang term with whatever extra data you want to + * identify this lock with. */ +ERTS_GLB_INLINE +void erts_lcnt_init_lock_info_x_idx(erts_lcnt_lock_info_carrier_t *carrier, int index, + const char *name, Uint16 flag, Eterm id); + +/** @brief Initializes a lock counter reference; this must be called prior to + * using any other functions in this module. */ +#define erts_lcnt_init_ref(ref) ethr_atomic_init(ref, (ethr_sint_t)NULL); + +/** @brief Atomically installs the given lock counters. Nops (and releases the + * provided carrier) if something was already installed. */ +void erts_lcnt_install(erts_lcnt_ref_t *ref, erts_lcnt_lock_info_carrier_t *carrier); + +/** @brief Atomically removes the currently installed lock counters. Nops if + * nothing was installed. */ +void erts_lcnt_uninstall(erts_lcnt_ref_t *ref); + +/** @brief Convenience macro to install a single lock counter of the given + * name and type. */ +#define erts_lcnt_install_new_lock_info(reference, name, flag) \ + erts_lcnt_install_new_lock_info_x(reference, name, flag, NIL) + +/** @copydoc erts_lcnt_install_new_lock_info + * @param id An immediate erlang term with whatever extra data you want to + * identify this lock with. */ +#define erts_lcnt_install_new_lock_info_x(reference, name, flag, id) \ + do { \ + erts_lcnt_lock_info_carrier_t *__carrier; \ + __carrier = erts_lcnt_create_lock_info_carrier(1); \ + erts_lcnt_init_lock_info_x_idx(__carrier, 0, name, flag, id); \ + erts_lcnt_install(reference, __carrier); \ + } while(0) + +/* -- Module initialization ------------------------------------------------ */ + +void erts_lcnt_pre_thr_init(void); +void erts_lcnt_post_thr_init(void); void erts_lcnt_late_init(void); -/* thread operations */ void erts_lcnt_thread_setup(void); void erts_lcnt_thread_exit_handler(void); -/* list operations (local) */ -erts_lcnt_lock_list_t *erts_lcnt_list_init(void); +/* -- BIF interface -------------------------------------------------------- */ -void erts_lcnt_list_insert(erts_lcnt_lock_list_t *list, erts_lcnt_lock_t *lock); -void erts_lcnt_list_delete(erts_lcnt_lock_list_t *list, erts_lcnt_lock_t *lock); - -/* lock operations (global) */ -void erts_lcnt_init_lock(erts_lcnt_lock_t *lock, char *name, Uint16 flag); -void erts_lcnt_init_lock_x(erts_lcnt_lock_t *lock, char *name, Uint16 flag, Eterm id); -void erts_lcnt_init_lock_empty(erts_lcnt_lock_t *lock); -void erts_lcnt_destroy_lock(erts_lcnt_lock_t *lock); +/** @brief Safely iterates through all entries in the given list. + * + * The referenced item will be valid until the next call to + * \c erts_lcnt_iterate_list after which point it may be destroyed; call + * erts_lcnt_retain_lock_info if you wish to hang on to it beyond that point. + * + * Iteration can be cancelled by calling erts_lcnt_release_lock_info on the + * iterator and breaking out of the loop. + * + * @param iterator The iteration variable; set the pointee to NULL to start + * iteration. + * @return 1 while the iterator is valid, 0 at the end of the list. */ +int erts_lcnt_iterate_list(erts_lcnt_lock_info_list_t *list, erts_lcnt_lock_info_t **iterator); -void erts_lcnt_lock(erts_lcnt_lock_t *lock); -void erts_lcnt_lock_opt(erts_lcnt_lock_t *lock, Uint16 option); -void erts_lcnt_lock_post(erts_lcnt_lock_t *lock); -void erts_lcnt_lock_post_x(erts_lcnt_lock_t *lock, char *file, unsigned int line); -void erts_lcnt_lock_unaquire(erts_lcnt_lock_t *lock); +/** @brief Clears the counter state of all locks, and releases all locks + * preserved through ERTS_LCNT_OPT_COPYSAVE (if any). */ +void erts_lcnt_clear_counters(void); -void erts_lcnt_unlock(erts_lcnt_lock_t *lock); -void erts_lcnt_unlock_opt(erts_lcnt_lock_t *lock, Uint16 option); +/** @brief Retrieves the global lock counter state. + * + * Note that the lists may be modified while you're mucking around with them. + * Always use \c erts_lcnt_iterate_list to enumerate them. */ +erts_lcnt_data_t erts_lcnt_get_data(void); -void erts_lcnt_trylock_opt(erts_lcnt_lock_t *lock, int res, Uint16 option); -void erts_lcnt_trylock(erts_lcnt_lock_t *lock, int res); +void erts_lcnt_retain_lock_info(erts_lcnt_lock_info_t *info); +void erts_lcnt_release_lock_info(erts_lcnt_lock_info_t *info); -/* bif interface */ Uint16 erts_lcnt_set_rt_opt(Uint16 opt); Uint16 erts_lcnt_clear_rt_opt(Uint16 opt); -void erts_lcnt_clear_counters(void); -char *erts_lcnt_lock_type(Uint16 type); -erts_lcnt_data_t *erts_lcnt_get_data(void); + +const char *erts_lcnt_lock_type(Uint16 type); + +/* -- Inline implementation ------------------------------------------------ */ + +/* The following is a hack to get the things we need from erl_thr_progress.h, + * which we can't #include without dependency hell breaking loose. + * + * The size of LcntThrPrgrLaterOp and value of the constant are verified at + * compile-time in erts_lcnt_pre_thr_init. */ + +int lcnt_thr_progress_unmanaged_delay__(void); +void lcnt_thr_progress_unmanaged_continue__(int handle); +typedef struct { Uint64 _[4]; } LcntThrPrgrLaterOp; +#define LCNT_THR_PRGR_DHANDLE_MANAGED -1 + +struct lcnt_lock_info_carrier_ { + ethr_atomic_t ref_count; + + void (*deallocate)(struct lcnt_lock_info_carrier_ *); + + LcntThrPrgrLaterOp release_entries; + + unsigned char entry_count; + erts_lcnt_lock_info_t entries[]; +}; + +typedef struct { + erts_lcnt_time_t timer; /* timer */ + int timer_set; /* bool */ + int lock_in_conflict; /* bool */ +} lcnt_thread_data_t__; + +extern ethr_tsd_key lcnt_thr_data_key__; + +/** @brief Some operations (eg erts_alloc or erts_thr_progress_unmanaged_delay) + * are unsafe in the early stages of initialization, so we're using this flag + * to know when we can move over to normal operation. */ +extern int lcnt_initialization_completed__; + +extern const int lcnt_log2_tab64__[]; + +ERTS_GLB_INLINE +int lcnt_log2__(Uint64 v); + +ERTS_GLB_INLINE +void lcnt_update_wait_histogram__(erts_lcnt_hist_t *hist, erts_lcnt_time_t *time_waited); + +ERTS_GLB_INLINE +void lcnt_update_stats__(erts_lcnt_lock_stats_t *stats, int lock_in_conflict, erts_lcnt_time_t *time_waited); + +ERTS_GLB_INLINE +erts_lcnt_lock_stats_t *lcnt_get_lock_stats__(erts_lcnt_lock_info_t *info, char *file, unsigned int line); + +ERTS_GLB_INLINE +void lcnt_dec_lock_state__(ethr_atomic_t *l_state); + +ERTS_GLB_INLINE +void lcnt_time__(erts_lcnt_time_t *time); + +ERTS_GLB_INLINE +void lcnt_time_add__(erts_lcnt_time_t *t, erts_lcnt_time_t *d); + +ERTS_GLB_INLINE +void lcnt_time_diff__(erts_lcnt_time_t *d, erts_lcnt_time_t *t1, erts_lcnt_time_t *t0); + +ERTS_GLB_INLINE +void lcnt_retain_carrier__(erts_lcnt_lock_info_carrier_t *carrier); + +ERTS_GLB_INLINE +void lcnt_release_carrier__(erts_lcnt_lock_info_carrier_t *carrier); + +ERTS_GLB_INLINE +lcnt_thread_data_t__ *lcnt_get_thread_data__(void); + +#if ERTS_GLB_INLINE_INCL_FUNC_DEF + +ERTS_GLB_INLINE +void lcnt_time__(erts_lcnt_time_t *time) { + /* + * erts_sys_hrtime() is the highest resolution + * we could find, it may or may not be monotonic... + */ + ErtsMonotonicTime mtime = erts_sys_hrtime(); + time->s = (unsigned long) (mtime / 1000000000LL); + time->ns = (unsigned long) (mtime - 1000000000LL*time->s); +} + +/* difference d must be non-negative */ + +ERTS_GLB_INLINE +void lcnt_time_add__(erts_lcnt_time_t *t, erts_lcnt_time_t *d) { + t->s += d->s; + t->ns += d->ns; + + t->s += t->ns / 1000000000LL; + t->ns = t->ns % 1000000000LL; +} + +ERTS_GLB_INLINE +void lcnt_time_diff__(erts_lcnt_time_t *d, erts_lcnt_time_t *t1, erts_lcnt_time_t *t0) { + long ds; + long dns; + + ds = t1->s - t0->s; + dns = t1->ns - t0->ns; + + /* the difference should not be able to get bigger than 1 sec in ns*/ + + if (dns < 0) { + ds -= 1; + dns += 1000000000LL; + } + + ASSERT(ds >= 0); + + d->s = ds; + d->ns = dns; +} + +ERTS_GLB_INLINE +int lcnt_log2__(Uint64 v) { + v |= v >> 1; + v |= v >> 2; + v |= v >> 4; + v |= v >> 8; + v |= v >> 16; + v |= v >> 32; + + return lcnt_log2_tab64__[((Uint64)((v - (v >> 1))*0x07EDD5E59A4E28C2)) >> 58]; +} + +ERTS_GLB_INLINE +void lcnt_update_wait_histogram__(erts_lcnt_hist_t *hist, erts_lcnt_time_t *time_waited) { + int idx; + + if(time_waited->s > 0 || time_waited->ns > ERTS_LCNT_HISTOGRAM_MAX_NS) { + idx = ERTS_LCNT_HISTOGRAM_SLOT_SIZE - 1; + } else { + unsigned long r = time_waited->ns >> ERTS_LCNT_HISTOGRAM_RSHIFT; + + idx = r ? lcnt_log2__(r) : 0; + } + + hist->ns[idx]++; +} + +ERTS_GLB_INLINE +void lcnt_update_stats__(erts_lcnt_lock_stats_t *stats, int lock_in_conflict, erts_lcnt_time_t *time_waited) { + ethr_atomic_inc(&stats->attempts); + + if(lock_in_conflict) { + ethr_atomic_inc(&stats->collisions); + } + + if(time_waited) { + stats->times_waited++; + + lcnt_time_add__(&stats->total_time_waited, time_waited); + lcnt_update_wait_histogram__(&stats->wait_time_histogram, time_waited); + } +} + +/* If we were installed while the lock was held, r/w_state will be 0 and we + * can't tell which unlock or unacquire operation was the last. To get around + * this we assume that all excess operations go *towards* zero rather than down + * to zero, eventually becoming consistent with the actual state once the lock + * is fully released. + * + * Conflicts might not be counted until the recorded state is fully consistent + * with the actual state, but there should be no other ill effects. */ + +ERTS_GLB_INLINE +void lcnt_dec_lock_state__(ethr_atomic_t *l_state) { + ethr_sint_t state = ethr_atomic_dec_read_acqb(l_state); + + /* We can not assume that state is >= -1 here; unlock and unacquire might + * bring it below -1 and race to increment it back. */ + + if(state < 0) { + ethr_atomic_inc_acqb(l_state); + } +} + +ERTS_GLB_INLINE +erts_lcnt_lock_stats_t *lcnt_get_lock_stats__(erts_lcnt_lock_info_t *info, char *file, unsigned int line) { + ASSERT(info->location_count >= 1 && info->location_count <= ERTS_LCNT_MAX_LOCK_LOCATIONS); + + if(erts_lcnt_rt_options & ERTS_LCNT_OPT_LOCATION) { + unsigned int i; + + for(i = 0; i < info->location_count; i++) { + erts_lcnt_lock_stats_t *stats = &info->location_stats[i]; + + if(stats->file == file && stats->line == line) { + return stats; + } + } + + if(info->location_count < ERTS_LCNT_MAX_LOCK_LOCATIONS) { + erts_lcnt_lock_stats_t *stats = &info->location_stats[info->location_count]; + + stats->file = file; + stats->line = line; + + info->location_count++; + + return stats; + } + } + + return &info->location_stats[0]; +} + +ERTS_GLB_INLINE +lcnt_thread_data_t__ *lcnt_get_thread_data__(void) { + lcnt_thread_data_t__ *eltd = (lcnt_thread_data_t__ *)ethr_tsd_get(lcnt_thr_data_key__); + + ASSERT(eltd); + + return eltd; +} + +ERTS_GLB_FORCE_INLINE +int erts_lcnt_open_ref(erts_lcnt_ref_t *ref, int *handle, erts_lcnt_lock_info_carrier_t **result) { + if(!*ethr_atomic_addr(ref) || !lcnt_initialization_completed__) { + return 0; + } + + (*handle) = lcnt_thr_progress_unmanaged_delay__(); + (*result) = (erts_lcnt_lock_info_carrier_t*)ethr_atomic_read(ref); + + if(*result) { + if(*handle != LCNT_THR_PRGR_DHANDLE_MANAGED) { + lcnt_retain_carrier__(*result); + lcnt_thr_progress_unmanaged_continue__(*handle); + } + + return 1; + } else if(*handle != LCNT_THR_PRGR_DHANDLE_MANAGED) { + lcnt_thr_progress_unmanaged_continue__(*handle); + } + + return 0; +} + +ERTS_GLB_FORCE_INLINE +void erts_lcnt_close_ref(int handle, erts_lcnt_lock_info_carrier_t *carrier) { + if(handle != LCNT_THR_PRGR_DHANDLE_MANAGED) { + lcnt_release_carrier__(carrier); + } +} + +ERTS_GLB_FORCE_INLINE +void erts_lcnt_lock(erts_lcnt_ref_t *ref) { + erts_lcnt_lock_info_carrier_t *carrier; + int handle; + + if(erts_lcnt_open_ref(ref, &handle, &carrier)) { + erts_lcnt_lock_idx(carrier, 0); + + erts_lcnt_close_ref(handle, carrier); + } +} + +ERTS_GLB_FORCE_INLINE +void erts_lcnt_lock_opt(erts_lcnt_ref_t *ref, Uint16 option) { + erts_lcnt_lock_info_carrier_t *carrier; + int handle; + + if(erts_lcnt_open_ref(ref, &handle, &carrier)) { + erts_lcnt_lock_opt_idx(carrier, 0, option); + + erts_lcnt_close_ref(handle, carrier); + } +} + +ERTS_GLB_FORCE_INLINE +void erts_lcnt_lock_post(erts_lcnt_ref_t *ref) { + erts_lcnt_lock_info_carrier_t *carrier; + int handle; + + if(erts_lcnt_open_ref(ref, &handle, &carrier)) { + erts_lcnt_lock_post_idx(carrier, 0); + + erts_lcnt_close_ref(handle, carrier); + } +} + +ERTS_GLB_FORCE_INLINE +void erts_lcnt_lock_post_x(erts_lcnt_ref_t *ref, char *file, unsigned int line) { + erts_lcnt_lock_info_carrier_t *carrier; + int handle; + + if(erts_lcnt_open_ref(ref, &handle, &carrier)) { + erts_lcnt_lock_post_x_idx(carrier, 0, file, line); + + erts_lcnt_close_ref(handle, carrier); + } +} + +ERTS_GLB_FORCE_INLINE +void erts_lcnt_lock_unacquire(erts_lcnt_ref_t *ref) { + erts_lcnt_lock_info_carrier_t *carrier; + int handle; + + if(erts_lcnt_open_ref(ref, &handle, &carrier)) { + erts_lcnt_lock_unacquire_idx(carrier, 0); + + erts_lcnt_close_ref(handle, carrier); + } +} + +ERTS_GLB_FORCE_INLINE +void erts_lcnt_unlock(erts_lcnt_ref_t *ref) { + erts_lcnt_lock_info_carrier_t *carrier; + int handle; + + if(erts_lcnt_open_ref(ref, &handle, &carrier)) { + erts_lcnt_unlock_idx(carrier, 0); + + erts_lcnt_close_ref(handle, carrier); + } +} + +ERTS_GLB_FORCE_INLINE +void erts_lcnt_unlock_opt(erts_lcnt_ref_t *ref, Uint16 option) { + erts_lcnt_lock_info_carrier_t *carrier; + int handle; + + if(erts_lcnt_open_ref(ref, &handle, &carrier)) { + erts_lcnt_unlock_opt_idx(carrier, 0, option); + + erts_lcnt_close_ref(handle, carrier); + } +} + +ERTS_GLB_FORCE_INLINE +void erts_lcnt_trylock(erts_lcnt_ref_t *ref, int result) { + erts_lcnt_lock_info_carrier_t *carrier; + int handle; + + if(erts_lcnt_open_ref(ref, &handle, &carrier)) { + erts_lcnt_trylock_idx(carrier, 0, result); + + erts_lcnt_close_ref(handle, carrier); + } +} + +ERTS_GLB_FORCE_INLINE +void erts_lcnt_trylock_opt(erts_lcnt_ref_t *ref, int result, Uint16 option) { + erts_lcnt_lock_info_carrier_t *carrier; + int handle; + + if(erts_lcnt_open_ref(ref, &handle, &carrier)) { + erts_lcnt_trylock_opt_idx(carrier, 0, result, option); + + erts_lcnt_close_ref(handle, carrier); + } +} + +ERTS_GLB_INLINE +void erts_lcnt_lock_idx(erts_lcnt_lock_info_carrier_t *carrier, int index) { + erts_lcnt_lock_opt_idx(carrier, index, ERTS_LCNT_LO_WRITE); +} + +ERTS_GLB_INLINE +void erts_lcnt_lock_opt_idx(erts_lcnt_lock_info_carrier_t *carrier, int index, Uint16 option) { + erts_lcnt_lock_info_t *info = &carrier->entries[index]; + + lcnt_thread_data_t__ *eltd = lcnt_get_thread_data__(); + + ASSERT(index < carrier->entry_count); + + ASSERT((option & ERTS_LCNT_LO_READ) || (option & ERTS_LCNT_LO_WRITE)); + + if(option & ERTS_LCNT_LO_WRITE) { + ethr_sint_t w_state, r_state; + + w_state = ethr_atomic_inc_read(&info->w_state) - 1; + r_state = ethr_atomic_read(&info->r_state); + + /* We cannot acquire w_lock if either w or r are taken */ + eltd->lock_in_conflict = (w_state > 0) || (r_state > 0); + } else { + ethr_sint_t w_state = ethr_atomic_read(&info->w_state); + + /* We cannot acquire r_lock if w_lock is taken */ + eltd->lock_in_conflict = (w_state > 0); + } + + if(option & ERTS_LCNT_LO_READ) { + ethr_atomic_inc(&info->r_state); + } + + if(eltd->lock_in_conflict) { + /* Only set the timer if nobody else has it. This should only happen + * when proc_locks acquires several locks "atomically." All other locks + * will block the thread when locked (w_state > 0) */ + if(eltd->timer_set == 0) { + lcnt_time__(&eltd->timer); + } + + eltd->timer_set++; + } +} + +ERTS_GLB_INLINE +void erts_lcnt_lock_post_idx(erts_lcnt_lock_info_carrier_t *carrier, int index) { + erts_lcnt_lock_post_x_idx(carrier, index, NULL, 0); +} + +ERTS_GLB_INLINE +void erts_lcnt_lock_post_x_idx(erts_lcnt_lock_info_carrier_t *carrier, int index, char *file, unsigned int line) { + erts_lcnt_lock_info_t *info = &carrier->entries[index]; + + lcnt_thread_data_t__ *eltd = lcnt_get_thread_data__(); + erts_lcnt_lock_stats_t *stats; + + ASSERT(index < carrier->entry_count); + +#ifdef LCNT_DEBUG_LOCK_FLOW + if(!(info->flag & (ERTS_LCNT_LT_RWMUTEX | ERTS_LCNT_LT_RWSPINLOCK))) { + ASSERT(ethr_atomic_inc_read(&info->flowstate) == 1); + } +#endif + + /* If the lock was in conflict, update the time spent waiting. */ + stats = lcnt_get_lock_stats__(info, file, line); + if(eltd->timer_set) { + erts_lcnt_time_t time_wait; + erts_lcnt_time_t timer; + + lcnt_time__(&timer); + + lcnt_time_diff__(&time_wait, &timer, &eltd->timer); + lcnt_update_stats__(stats, eltd->lock_in_conflict, &time_wait); + + eltd->timer_set--; + + ASSERT(eltd->timer_set >= 0); + } else { + lcnt_update_stats__(stats, eltd->lock_in_conflict, NULL); + } +} + +ERTS_GLB_INLINE +void erts_lcnt_unlock_idx(erts_lcnt_lock_info_carrier_t *carrier, int index) { +#ifdef LCNT_DEBUG_LOCK_FLOW + erts_lcnt_lock_info_t *info = &carrier->entries[index]; + + ASSERT(ethr_atomic_dec_read(&info->flowstate) == 0); +#endif + + ASSERT(index < carrier->entry_count); + + erts_lcnt_unlock_opt_idx(carrier, index, ERTS_LCNT_LO_WRITE); +} + +ERTS_GLB_INLINE +void erts_lcnt_unlock_opt_idx(erts_lcnt_lock_info_carrier_t *carrier, int index, Uint16 option) { + erts_lcnt_lock_info_t *info = &carrier->entries[index]; + + ASSERT(index < carrier->entry_count); + + ASSERT((option & ERTS_LCNT_LO_READ) || (option & ERTS_LCNT_LO_WRITE)); + + if(option & ERTS_LCNT_LO_WRITE) { + lcnt_dec_lock_state__(&info->w_state); + } + + if(option & ERTS_LCNT_LO_READ) { + lcnt_dec_lock_state__(&info->r_state); + } +} + +ERTS_GLB_INLINE +void erts_lcnt_lock_unacquire_idx(erts_lcnt_lock_info_carrier_t *carrier, int index) { + erts_lcnt_lock_info_t *info = &carrier->entries[index]; + + ASSERT(index < carrier->entry_count); + + lcnt_dec_lock_state__(&info->w_state); +} + +ERTS_GLB_INLINE +void erts_lcnt_trylock_idx(erts_lcnt_lock_info_carrier_t *carrier, int index, int result) { +#ifdef LCNT_DEBUG_LOCK_FLOW + erts_lcnt_lock_info_t *info = &carrier->entries[index]; + + ASSERT(result == EBUSY || ethr_atomic_inc_read(&info->flowstate) == 1); +#endif + + ASSERT(index < carrier->entry_count); + + erts_lcnt_trylock_opt_idx(carrier, index, result, ERTS_LCNT_LO_WRITE); +} + +ERTS_GLB_INLINE +void erts_lcnt_trylock_opt_idx(erts_lcnt_lock_info_carrier_t *carrier, int index, int result, Uint16 option) { + erts_lcnt_lock_info_t *info = &carrier->entries[index]; + + ASSERT(index < carrier->entry_count); + + ASSERT((option & ERTS_LCNT_LO_READ) || (option & ERTS_LCNT_LO_WRITE)); + + if(result != EBUSY) { + if(option & ERTS_LCNT_LO_WRITE) { + ethr_atomic_inc(&info->w_state); + } + + if(option & ERTS_LCNT_LO_READ) { + ethr_atomic_inc(&info->r_state); + } + + lcnt_update_stats__(&info->location_stats[0], 0, NULL); + } else { + ethr_atomic_inc(&info->location_stats[0].attempts); + ethr_atomic_inc(&info->location_stats[0].collisions); + } +} + +ERTS_GLB_INLINE +void erts_lcnt_init_lock_info_x_idx(erts_lcnt_lock_info_carrier_t *carrier, int index, + const char *name, Uint16 flag, Eterm id) { + erts_lcnt_lock_info_t *info = &carrier->entries[index]; + + ASSERT(is_immed(id)); + + info->flag = flag; + info->name = name; + info->id = id; +} + +ERTS_GLB_INLINE +void lcnt_retain_carrier__(erts_lcnt_lock_info_carrier_t *carrier) { +#ifdef DEBUG + ASSERT(ethr_atomic_inc_read_acqb(&carrier->ref_count) >= 2); +#else + ethr_atomic_inc_acqb(&carrier->ref_count); +#endif +} + +ERTS_GLB_INLINE +void lcnt_release_carrier__(erts_lcnt_lock_info_carrier_t *carrier) { + ethr_sint_t count = ethr_atomic_dec_read_relb(&carrier->ref_count); + + ASSERT(count >= 0); + + if(count == 0) { + carrier->deallocate(carrier); + } +} + +#endif #endif /* ifdef ERTS_ENABLE_LOCK_COUNT */ #endif /* ifndef ERTS_LOCK_COUNT_H__ */ |