[Minor] Store stddev for counters

diff --git a/src/libserver/symbols_cache.c b/src/libserver/symbols_cache.c
index a47500968c38169645c63b1a0be5293f31178fc4..b2a36350085c3055a3252b82f79c87597d4d5967 100644 (file)
--- a/src/libserver/symbols_cache.c
+++ b/src/libserver/symbols_cache.c
@@ -80,7 +80,8 @@ struct symbols_cache {
 };
 
 struct counter_data {
-       gdouble value;
+       gdouble mean;
+       gdouble stddev;
        gint number;
 };
 
@@ -328,12 +329,14 @@ rspamd_set_counter (struct cache_item *item, gdouble value)
 
        /* Cumulative moving average using per-process counter data */
        if (cd->number == 0) {
-               cd->value = 0;
+               cd->mean = 0;
+               cd->stddev = 0;
        }
 
-       cd->value = cd->value + (value - cd->value) / (gdouble)(++cd->number);
+       cd->mean += (value - cd->mean) / (gdouble)(++cd->number);
+       cd->stddev += (value - cd->mean) * (value - cd->mean);
 
-       return cd->value;
+       return cd->mean;
 }
 
 static void
@@ -1840,9 +1843,9 @@ rspamd_symbols_cache_resort_cb (gint fd, short what, gpointer ud)
                        if (item->cd->number > 0) {
                                item->st->avg_counter += item->cd->number + 1;
                                item->st->avg_time = item->st->avg_time +
-                                               (item->cd->value - item->st->avg_time) /
+                                               (item->cd->mean - item->st->avg_time) /
                                                                (gdouble)item->st->avg_counter;
-                               item->cd->value = item->st->avg_time;
+                               item->cd->mean = item->st->avg_time;
                                item->cd->number = item->st->avg_counter;
                        }
                }