/**
* mongoc_counters_register:
* @counters: A mongoc_counter_t.
* @num: The counter number.
* @category: The counter category.
* @name: THe counter name.
* @description The counter description.
*
* Registers a new counter in the memory segment for counters. If the counters
* are exported over shared memory, it will be made available.
*
* Returns: The offset to the data for the counters values.
*/
static size_t
mongoc_counters_register (mongoc_counters_t *counters,
uint32_t num,
const char *category,
const char *name,
const char *description)
{
mongoc_counter_info_t *infos;
char *segment;
int n_cpu;
BSON_ASSERT(counters);
BSON_ASSERT(category);
BSON_ASSERT(name);
BSON_ASSERT(description);
/*
* Implementation Note:
*
* The memory barrier is required so that all of the above has been
* completed. Then increment the n_counters so that a reading application
* only knows about the counter after we have initialized it.
*/
n_cpu = _mongoc_get_cpu_count();
segment = (char *)counters;
infos = (mongoc_counter_info_t *)(segment + counters->infos_offset);
infos = &infos[counters->n_counters];
infos->slot = num % SLOTS_PER_CACHELINE;
infos->offset = (counters->values_offset +
((num / SLOTS_PER_CACHELINE) *
n_cpu * sizeof(mongoc_counter_slots_t)));
bson_strcpy_w_null(infos->category, category, sizeof infos->category);
bson_strcpy_w_null(infos->name, name, sizeof infos->name);
bson_strcpy_w_null(infos->description, description, sizeof infos->description);
bson_memory_barrier ();
counters->n_counters++;
return infos->offset;
}
/**
* mongoc_counters_init:
*
* Initializes the mongoc counters system. This should be run on library
* initialization using the GCC constructor attribute.
*/
void
_mongoc_counters_init (void)
{
mongoc_counter_info_t *info;
mongoc_counters_t *counters;
size_t infos_size;
size_t off;
size_t size;
char *segment;
size = mongoc_counters_calc_size();
segment = mongoc_counters_alloc(size);
infos_size = LAST_COUNTER * sizeof *info;
counters = (mongoc_counters_t *)segment;
counters->n_cpu = _mongoc_get_cpu_count();
counters->n_counters = 0;
counters->infos_offset = sizeof *counters;
counters->values_offset = (uint32_t)(counters->infos_offset + infos_size);
BSON_ASSERT ((counters->values_offset % 64) == 0);
#define COUNTER(ident, Category, Name, Desc) \
off = mongoc_counters_register(counters, COUNTER_##ident, Category, Name, Desc); \
__mongoc_counter_##ident.cpus = (void *)(segment + off);
#include "mongoc-counters.defs"
#undef COUNTER
/*
* NOTE:
*
* Only update the size of the shared memory area for the client after
* we have initialized the rest of the counters. Don't forget our memory
* barrier to prevent compiler reordering.
*/
bson_memory_barrier ();
counters->size = (uint32_t)size;
}
static void
test3 (void)
{
bson_memory_barrier ();
}
