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Align statistics to cache lines

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Aligning the statistics object indices to cache line size reduces the CPU
overhead of gathering the statistics. This allows the statistics to more
accurately measure the polling system without the measurement affecting
the outcome.
This commit is contained in:
Markus Makela
2016-12-09 17:39:31 +02:00
parent 5cb738ae03
commit 49aa23468d
6 changed files with 127 additions and 43 deletions
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51
include/maxscale/statistics.h
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@ -40,13 +40,18 @@ enum ts_stats_type
TS_STATS_AVG /**< Average of all values */
};
/** stats_init should be called only once */
void ts_stats_init();
/** No-op for now */
void ts_stats_end();
/**
* @brief Allocate a new statistics object
*
* @return New statistics object or NULL if memory allocation failed
*/
ts_stats_t ts_stats_alloc();
/**
* @brief Free statistics
*
* @param stats Statistics to free
*/
void ts_stats_free(ts_stats_t stats);
/**
@ -66,11 +71,7 @@ int64_t ts_stats_get(ts_stats_t stats, enum ts_stats_type type);
* @param stats Statistics to add to
* @param thread_id ID of thread
*/
static void inline
ts_stats_increment(ts_stats_t stats, int thread_id)
{
((int64_t*)stats)[thread_id]++;
}
void ts_stats_increment(ts_stats_t stats, int thread_id);
/**
* @brief Assign a value to a statistics element
@ -81,11 +82,7 @@ ts_stats_increment(ts_stats_t stats, int thread_id)
* @param value Value to set to
* @param thread_id ID of thread
*/
static void inline
ts_stats_set(ts_stats_t stats, int value, int thread_id)
{
((int64_t*)stats)[thread_id] = value;
}
void ts_stats_set(ts_stats_t stats, int value, int thread_id);
/**
* @brief Assign the maximum value to a statistics element
@ -96,16 +93,7 @@ ts_stats_set(ts_stats_t stats, int value, int thread_id)
* @param value Value to set to
* @param thread_id ID of thread
*/
static void inline
ts_stats_set_max(ts_stats_t stats, int value, int thread_id)
{
int64_t *p = (int64_t*) stats;
if (value > p[thread_id])
{
p[thread_id] = value;
}
}
void ts_stats_set_max(ts_stats_t stats, int value, int thread_id);
/**
* @brief Assign the minimum value to a statistics element
@ -116,15 +104,6 @@ ts_stats_set_max(ts_stats_t stats, int value, int thread_id)
* @param value Value to set to
* @param thread_id ID of thread
*/
static void inline
ts_stats_set_min(ts_stats_t stats, int value, int thread_id)
{
int64_t *p = (int64_t*) stats;
if (value < p[thread_id])
{
p[thread_id] = value;
}
}
void ts_stats_set_min(ts_stats_t stats, int value, int thread_id);
MXS_END_DECLS