diff options
Diffstat (limited to 'web/api/queries/ses')
| -rw-r--r-- | web/api/queries/ses/Makefile.am | 8 | ||||
| -rw-r--r-- | web/api/queries/ses/README.md | 65 | ||||
| -rw-r--r-- | web/api/queries/ses/ses.c | 8 | ||||
| -rw-r--r-- | web/api/queries/ses/ses.h | 92 |
4 files changed, 0 insertions, 173 deletions
diff --git a/web/api/queries/ses/Makefile.am b/web/api/queries/ses/Makefile.am deleted file mode 100644 index 161784b8f..000000000 --- a/web/api/queries/ses/Makefile.am +++ /dev/null @@ -1,8 +0,0 @@ -# SPDX-License-Identifier: GPL-3.0-or-later - -AUTOMAKE_OPTIONS = subdir-objects -MAINTAINERCLEANFILES = $(srcdir)/Makefile.in - -dist_noinst_DATA = \ - README.md \ - $(NULL) diff --git a/web/api/queries/ses/README.md b/web/api/queries/ses/README.md deleted file mode 100644 index a06f646ef..000000000 --- a/web/api/queries/ses/README.md +++ /dev/null @@ -1,65 +0,0 @@ -<!-- -title: "Single (or Simple) Exponential Smoothing (`ses`)" -sidebar_label: "Single (or Simple) Exponential Smoothing (`ses`)" -custom_edit_url: https://github.com/netdata/netdata/edit/master/web/api/queries/ses/README.md -learn_status: "Published" -learn_topic_type: "References" -learn_rel_path: "Developers/Web/Api/Queries" ---> - -# Single (or Simple) Exponential Smoothing (`ses`) - -> This query is also available as `ema` and `ewma`. - -An exponential moving average (`ema`), also known as an exponentially weighted moving average (`ewma`) -is a first-order infinite impulse response filter that applies weighting factors which decrease -exponentially. The weighting for each older datum decreases exponentially, never reaching zero. - -In simple terms, this is like an average value, but more recent values are given more weight. - -Netdata automatically adjusts the weight (`alpha`) based on the number of values processed, -using the formula: - -``` -window = max(number of values, 15) -alpha = 2 / (window + 1) -``` - -You can change the fixed value `15` by setting in `netdata.conf`: - -``` -[web] - ses max window = 15 -``` - -## how to use - -Use it in alerts like this: - -``` - alarm: my_alert - on: my_chart -lookup: ses -1m unaligned of my_dimension - warn: $this > 1000 -``` - -`ses` does not change the units. For example, if the chart units is `requests/sec`, the exponential -moving average will be again expressed in the same units. - -It can also be used in APIs and badges as `&group=ses` in the URL. - -## Examples - -Examining last 1 minute `successful` web server responses: - --  --  --  --  - -## References - -- <https://en.wikipedia.org/wiki/Moving_average#exponential-moving-average> -- <https://en.wikipedia.org/wiki/Exponential_smoothing>. - - diff --git a/web/api/queries/ses/ses.c b/web/api/queries/ses/ses.c deleted file mode 100644 index 39eb445a0..000000000 --- a/web/api/queries/ses/ses.c +++ /dev/null @@ -1,8 +0,0 @@ -// SPDX-License-Identifier: GPL-3.0-or-later - -#include "ses.h" - - -// ---------------------------------------------------------------------------- -// single exponential smoothing - diff --git a/web/api/queries/ses/ses.h b/web/api/queries/ses/ses.h deleted file mode 100644 index de8645ff0..000000000 --- a/web/api/queries/ses/ses.h +++ /dev/null @@ -1,92 +0,0 @@ -// SPDX-License-Identifier: GPL-3.0-or-later - -#ifndef NETDATA_API_QUERIES_SES_H -#define NETDATA_API_QUERIES_SES_H - -#include "../query.h" -#include "../rrdr.h" - -struct tg_ses { - NETDATA_DOUBLE alpha; - NETDATA_DOUBLE alpha_other; - NETDATA_DOUBLE level; - size_t count; -}; - -static size_t tg_ses_max_window_size = 15; - -static inline void tg_ses_init(void) { - long long ret = config_get_number(CONFIG_SECTION_WEB, "ses max tg_des_window", (long long)tg_ses_max_window_size); - if(ret <= 1) { - config_set_number(CONFIG_SECTION_WEB, "ses max tg_des_window", (long long)tg_ses_max_window_size); - } - else { - tg_ses_max_window_size = (size_t) ret; - } -} - -static inline NETDATA_DOUBLE tg_ses_window(RRDR *r, struct tg_ses *g) { - (void)g; - - NETDATA_DOUBLE points; - if(r->view.group == 1) { - // provide a running DES - points = (NETDATA_DOUBLE)r->time_grouping.points_wanted; - } - else { - // provide a SES with flush points - points = (NETDATA_DOUBLE)r->view.group; - } - - return (points > (NETDATA_DOUBLE)tg_ses_max_window_size) ? (NETDATA_DOUBLE)tg_ses_max_window_size : points; -} - -static inline void tg_ses_set_alpha(RRDR *r, struct tg_ses *g) { - // https://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average - // A commonly used value for alpha is 2 / (N + 1) - g->alpha = 2.0 / (tg_ses_window(r, g) + 1.0); - g->alpha_other = 1.0 - g->alpha; -} - -static inline void tg_ses_create(RRDR *r, const char *options __maybe_unused) { - struct tg_ses *g = (struct tg_ses *)onewayalloc_callocz(r->internal.owa, 1, sizeof(struct tg_ses)); - tg_ses_set_alpha(r, g); - g->level = 0.0; - r->time_grouping.data = g; -} - -// resets when switches dimensions -// so, clear everything to restart -static inline void tg_ses_reset(RRDR *r) { - struct tg_ses *g = (struct tg_ses *)r->time_grouping.data; - g->level = 0.0; - g->count = 0; -} - -static inline void tg_ses_free(RRDR *r) { - onewayalloc_freez(r->internal.owa, r->time_grouping.data); - r->time_grouping.data = NULL; -} - -static inline void tg_ses_add(RRDR *r, NETDATA_DOUBLE value) { - struct tg_ses *g = (struct tg_ses *)r->time_grouping.data; - - if(unlikely(!g->count)) - g->level = value; - - g->level = g->alpha * value + g->alpha_other * g->level; - g->count++; -} - -static inline NETDATA_DOUBLE tg_ses_flush(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr) { - struct tg_ses *g = (struct tg_ses *)r->time_grouping.data; - - if(unlikely(!g->count || !netdata_double_isnumber(g->level))) { - *rrdr_value_options_ptr |= RRDR_VALUE_EMPTY; - return 0.0; - } - - return g->level; -} - -#endif //NETDATA_API_QUERIES_SES_H |