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libosmocore/src/stat_item.c

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/*! \file stat_item.c
* utility routines for keeping statistical values */
/*
* (C) 2009-2010 by Harald Welte <laforge@gnumonks.org>
* (C) 2015 by sysmocom - s.f.m.c. GmbH
*
* All Rights Reserved
*
* SPDX-License-Identifier: GPL-2.0+
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
/*! \addtogroup osmo_stat_item
* @{
*
* This osmo_stat_item module adds instrumentation capabilities to
* gather measurement and statistical values in a similar fashion to
* what we have as \ref osmo_counter_group.
*
* As opposed to counters, osmo_stat_item do not increment but consist
* of a configurable-sized FIFO, which can store not only the current
* (most recent) value, but also historic values.
*
* The only supported value type is an int32_t.
*
* Getting values from osmo_stat_item is usually done at a high level
* through the stats API (stats.c). It uses item->stats_next_id to
* store what has been sent to all enabled reporters. It is also
* possible to read from osmo_stat_item directly, without modifying
* its state, by storing next_id outside of osmo_stat_item.
*
* Each value stored in the FIFO of an osmo_stat_item has an associated
* value_id. The value_id is increased with each value, so (until the
* counter wraps) more recent values will have higher values.
*
* When a new value is set, the oldest value in the FIFO gets silently
* overwritten. Lost values are skipped when getting values from the
* item.
*
*/
/* Struct overview:
*
* Group and item descriptions:
* Each group description exists once as osmo_stat_item_group_desc,
* each such group description lists N osmo_stat_item_desc, i.e. describes N stat items.
*
* Actual stats:
* The global osmo_stat_item_groups llist contains all group instances, each points at a group description.
* This list mixes all types of groups in a single llist, where each instance points at its group desc and has an index.
* There are one or more instances of each group, each storing stats for a distinct object (for example, one description
* for a BTS group, and any number of BTS instances with independent stats). A group is identified by a group index nr
* and possibly also a given name for that particular index (e.g. in osmo-mgw, a group instance is named
* "virtual-trunk-0" and can be looked up by that name instead of its more or less arbitrary group index number).
*
* Each group instance contains one osmo_stat_item instance per global stat item description.
* Each osmo_stat_item keeps track of the values for the current reporting period (min, last, max, sum, n),
* and also stores the set of values reported at the end of the previous reporting period.
*
* const osmo_stat_item_group_desc foo
* +-- group_name_prefix = "foo"
* +-- item_desc[] (array of osmo_stat_item_desc)
* +-- osmo_stat_item_desc bar
* | +-- name = "bar"
* | +-- description
* | +-- unit
* | +-- default_value
* |
* +-- osmo_stat_item_desc: baz
* +-- ...
*
* const osmo_stat_item_group_desc moo
* +-- group_name_prefix = "moo"
* +-- item_desc[]
* +-- osmo_stat_item_desc goo
* | +-- name = "goo"
* | +-- description
* | +-- unit
* | +-- default_value
* |
* +-- osmo_stat_item_desc: loo
* +-- ...
*
* osmo_stat_item_groups (llist of osmo_stat_item_group)
* |
* +-- group: foo[0]
* | +-- desc --> osmo_stat_item_group_desc foo
* | +-- idx = 0
* | +-- name = NULL (no given name for this group instance)
* | +-- items[]
* | |
* | [0] --> osmo_stat_item instance for "bar"
* | | +-- desc --> osmo_stat_item_desc bar (see above)
* | | +-- value.{min, last, max, n, sum}
* | | +-- reported.{min, last, max, n, sum}
* | |
* | [1] --> osmo_stat_item instance for "baz"
* | | +-- desc --> osmo_stat_item_desc baz
* | | +-- value.{min, last, max, n, sum}
* | | +-- reported.{min, last, max, n, sum}
* | .
* | :
* |
* +-- group: foo[1]
* | +-- desc --> osmo_stat_item_group_desc foo
* | +-- idx = 1
* | +-- name = "special-foo" (instance can be looked up by this index-name)
* | +-- items[]
* | |
* | [0] --> osmo_stat_item instance for "bar"
* | | +-- desc --> osmo_stat_item_desc bar
* | | +-- value.{min, last, max, n, sum}
* | | +-- reported.{min, last, max, n, sum}
* | |
* | [1] --> osmo_stat_item instance for "baz"
* | | +-- desc --> osmo_stat_item_desc baz
* | | +-- value.{min, last, max, n, sum}
* | | +-- reported.{min, last, max, n, sum}
* | .
* | :
* |
* +-- group: moo[0]
* | +-- desc --> osmo_stat_item_group_desc moo
* | +-- idx = 0
* | +-- name = NULL
* | +-- items[]
* | |
* | [0] --> osmo_stat_item instance for "goo"
* | | +-- desc --> osmo_stat_item_desc goo
* | | +-- value.{min, last, max, n, sum}
* | | +-- reported.{min, last, max, n, sum}
* | |
* | [1] --> osmo_stat_item instance for "loo"
* | | +-- desc --> osmo_stat_item_desc loo
* | | +-- value.{min, last, max, n, sum}
* | | +-- reported.{min, last, max, n, sum}
* | .
* | :
* .
* :
*
*/
#include <stdint.h>
#include <string.h>
#include <osmocom/core/utils.h>
#include <osmocom/core/linuxlist.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/timer.h>
#include <osmocom/core/stat_item.h>
#include <stat_item_internal.h>
/*! global list of stat_item groups */
static LLIST_HEAD(osmo_stat_item_groups);
/*! talloc context from which we allocate */
static void *tall_stat_item_ctx;
/*! Allocate a new group of counters according to description.
* Allocate a group of stat items described in \a desc from talloc context \a ctx,
* giving the new group the index \a idx.
* \param[in] ctx \ref talloc context
* \param[in] desc Statistics item group description
* \param[in] idx Index of new stat item group
*/
struct osmo_stat_item_group *osmo_stat_item_group_alloc(void *ctx,
const struct osmo_stat_item_group_desc *group_desc,
unsigned int idx)
{
unsigned int group_size;
unsigned int item_idx;
struct osmo_stat_item *items;
struct osmo_stat_item_group *group;
group_size = sizeof(struct osmo_stat_item_group) +
group_desc->num_items * sizeof(struct osmo_stat_item *);
if (!ctx)
ctx = tall_stat_item_ctx;
group = talloc_zero_size(ctx, group_size);
if (!group)
return NULL;
group->desc = group_desc;
group->idx = idx;
items = talloc_array(group, struct osmo_stat_item, group_desc->num_items);
OSMO_ASSERT(items);
for (item_idx = 0; item_idx < group_desc->num_items; item_idx++) {
struct osmo_stat_item *item = &items[item_idx];
const struct osmo_stat_item_desc *item_desc = &group_desc->item_desc[item_idx];
group->items[item_idx] = item;
*item = (struct osmo_stat_item){
.desc = item_desc,
.value = {
.n = 0,
.last = item_desc->default_value,
.min = item_desc->default_value,
.max = item_desc->default_value,
.sum = 0,
},
};
}
llist_add(&group->list, &osmo_stat_item_groups);
return group;
}
/*! Free the memory for the specified group of stat items */
void osmo_stat_item_group_free(struct osmo_stat_item_group *grp)
{
if (!grp)
return;
llist_del(&grp->list);
talloc_free(grp);
}
/*! Get statistics item from group, identified by index idx
* \param[in] grp Rate counter group
* \param[in] idx Index of the counter to retrieve
* \returns rate counter requested
*/
struct osmo_stat_item *osmo_stat_item_group_get_item(struct osmo_stat_item_group *grp, unsigned int idx)
{
return grp->items[idx];
}
/*! Set a name for the statistics item group to be used instead of index value
at report time.
* \param[in] statg Statistics item group
* \param[in] name Name identifier to assign to the statistics item group
*/
void osmo_stat_item_group_set_name(struct osmo_stat_item_group *statg, const char *name)
{
osmo_talloc_replace_string(statg, &statg->name, name);
}
/*! Increase the stat_item to the given value.
* This function adds a new value for the given stat_item at the end of
* the FIFO.
* \param[in] item The stat_item whose \a value we want to set
* \param[in] value The numeric value we want to store at end of FIFO
*/
void osmo_stat_item_inc(struct osmo_stat_item *item, int32_t value)
{
osmo_stat_item_set(item, item->value.last + value);
}
/*! Descrease the stat_item to the given value.
* This function adds a new value for the given stat_item at the end of
* the FIFO.
* \param[in] item The stat_item whose \a value we want to set
* \param[in] value The numeric value we want to store at end of FIFO
*/
void osmo_stat_item_dec(struct osmo_stat_item *item, int32_t value)
{
osmo_stat_item_set(item, item->value.last - value);
}
/*! Set the a given stat_item to the given value.
* This function adds a new value for the given stat_item at the end of
* the FIFO.
* \param[in] item The stat_item whose \a value we want to set
* \param[in] value The numeric value we want to store at end of FIFO
*/
void osmo_stat_item_set(struct osmo_stat_item *item, int32_t value)
{
item->value.last = value;
if (item->value.n == 0) {
/* No values recorded yet, clamp min and max to this first value. */
item->value.min = item->value.max = value;
/* Overwrite any cruft remaining in value.sum */
item->value.sum = value;
item->value.n = 1;
} else {
item->value.min = OSMO_MIN(item->value.min, value);
item->value.max = OSMO_MAX(item->value.max, value);
item->value.sum += value;
item->value.n++;
}
}
/*! Indicate that a reporting period has elapsed, and prepare the stat item for a new period of collecting min/max/avg.
* \param item Stat item to flush.
*/
void osmo_stat_item_flush(struct osmo_stat_item *item)
{
item->reported = item->value;
/* Indicate a new reporting period: no values have been received, but the previous value.last remains unchanged
* for the case that an entire period elapses without a new value appearing. */
item->value.n = 0;
item->value.sum = 0;
/* Also for the case that an entire period elapses without any osmo_stat_item_set(), put the min and max to the
* last value. As soon as one osmo_stat_item_set() occurs, these are both set to the new value (when n is still
* zero from above). */
item->value.min = item->value.max = item->value.last;
}
/*! Initialize the stat item module. Call this once from your program.
* \param[in] tall_ctx Talloc context from which this module allocates */
int osmo_stat_item_init(void *tall_ctx)
{
tall_stat_item_ctx = tall_ctx;
return 0;
}
/*! Search for item group based on group name and index
* \param[in] name Name of stats_item_group we want to find
* \param[in] idx Index of the group we want to find
* \returns pointer to group, if found; NULL otherwise */
struct osmo_stat_item_group *osmo_stat_item_get_group_by_name_idx(
const char *name, const unsigned int idx)
{
struct osmo_stat_item_group *statg;
llist_for_each_entry(statg, &osmo_stat_item_groups, list) {
if (!statg->desc)
continue;
if (!strcmp(statg->desc->group_name_prefix, name) &&
statg->idx == idx)
return statg;
}
return NULL;
}
/*! Search for item group based on group name and index's name.
* \param[in] name Name of stats_item_group we want to find.
* \param[in] idx_name Index of the group we want to find, by the index's name (osmo_stat_item_group->name).
* \returns pointer to group, if found; NULL otherwise. */
struct osmo_stat_item_group *osmo_stat_item_get_group_by_name_idxname(const char *group_name, const char *idx_name)
{
struct osmo_stat_item_group *statg;
llist_for_each_entry(statg, &osmo_stat_item_groups, list) {
if (!statg->desc || !statg->name)
continue;
if (strcmp(statg->desc->group_name_prefix, group_name))
continue;
if (strcmp(statg->name, idx_name))
continue;
return statg;
}
return NULL;
}
/*! Search for item based on group + item name
* \param[in] statg group in which to search for the item
* \param[in] name name of item to search within \a statg
* \returns pointer to item, if found; NULL otherwise */
const struct osmo_stat_item *osmo_stat_item_get_by_name(
const struct osmo_stat_item_group *statg, const char *name)
{
int i;
const struct osmo_stat_item_desc *item_desc;
if (!statg->desc)
return NULL;
for (i = 0; i < statg->desc->num_items; i++) {
item_desc = &statg->desc->item_desc[i];
if (!strcmp(item_desc->name, name)) {
return statg->items[i];
}
}
return NULL;
}
/*! Iterate over all items in group, call user-supplied function on each
* \param[in] statg stat_item group over whose items to iterate
* \param[in] handle_item Call-back function, aborts if rc < 0
* \param[in] data Private data handed through to \a handle_item
*/
int osmo_stat_item_for_each_item(struct osmo_stat_item_group *statg,
osmo_stat_item_handler_t handle_item, void *data)
{
int rc = 0;
int i;
for (i = 0; i < statg->desc->num_items; i++) {
struct osmo_stat_item *item = statg->items[i];
rc = handle_item(statg, item, data);
if (rc < 0)
return rc;
}
return rc;
}
/*! Iterate over all stat_item groups in system, call user-supplied function on each
* \param[in] handle_group Call-back function, aborts if rc < 0
* \param[in] data Private data handed through to \a handle_group
*/
int osmo_stat_item_for_each_group(osmo_stat_item_group_handler_t handle_group, void *data)
{
struct osmo_stat_item_group *statg;
int rc = 0;
llist_for_each_entry(statg, &osmo_stat_item_groups, list) {
rc = handle_group(statg, data);
if (rc < 0)
return rc;
}
return rc;
}
/*! Get the last (freshest) value. */
int32_t osmo_stat_item_get_last(const struct osmo_stat_item *item)
{
return item->value.last;
}
/*! Remove all values of a stat item
* \param[in] item stat item to reset
*/
void osmo_stat_item_reset(struct osmo_stat_item *item)
{
item->value.sum = 0;
item->value.n = 0;
item->value.last = item->value.min = item->value.max = item->desc->default_value;
}
/*! Reset all osmo stat items in a group
* \param[in] statg stat item group to reset
*/
void osmo_stat_item_group_reset(struct osmo_stat_item_group *statg)
{
int i;
for (i = 0; i < statg->desc->num_items; i++) {
struct osmo_stat_item *item = statg->items[i];
osmo_stat_item_reset(item);
}
}
/*! Return the description for an osmo_stat_item. */
const struct osmo_stat_item_desc *osmo_stat_item_get_desc(struct osmo_stat_item *item)
{
return item->desc;
}
/*! @} */
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