Compute MiRA's moving average and standard deviation after computing the

current measurement, not before.

The MiRA paper mentions these calculations in the order we implemented them.
But the moving average and standard deviation depend on the value of the
goodput measurement, not the other way around.

ok tb@

1 files changed, 10 insertions, 10 deletions

diff --git a/sys/net80211/ieee80211_mira.c b/sys/net80211/ieee80211_mira.c
index f55320b927c..55ba68c75e1 100644
--- a/sys/net80211/ieee80211_mira.c
+++ b/sys/net80211/ieee80211_mira.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ieee80211_mira.c,v 1.23 2020/03/05 11:52:18 stsp Exp $	*/
+/*	$OpenBSD: ieee80211_mira.c,v 1.24 2020/03/29 08:14:05 stsp Exp $	*/
 
 /*
  * Copyright (c) 2016 Stefan Sperling <stsp@openbsd.org>
@@ -454,6 +454,15 @@ ieee80211_mira_update_stats(struct ieee80211_mira_node *mn,
 	 * is tuned towards our fixed-point number format.
 	 */
 
+	g->average_agg = MIRA_FP_MUL(MIRA_FP_1 - alpha, g->average_agg);
+	g->average_agg += MIRA_FP_MUL(alpha, agglen);
+
+	toverhead = ieee80211_mira_toverhead(mn, ic, ni);
+	toverhead = MIRA_FP_MUL(toverhead, rate);
+	g->measured = MIRA_FP_DIV(MIRA_FP_1 - sfer, MIRA_FP_1 +
+	    MIRA_FP_DIV(toverhead, MIRA_FP_MUL(ampdu_size, g->average_agg)));
+	g->measured = MIRA_FP_MUL(g->measured, rate);
+
 	g->average = MIRA_FP_MUL(MIRA_FP_1 - alpha, g->average);
 	g->average += MIRA_FP_MUL(alpha, g->measured);
 
@@ -463,15 +472,6 @@ ieee80211_mira_update_stats(struct ieee80211_mira_node *mn,
 	else
 		delta = g->measured - g->average;
 	g->stddeviation += MIRA_FP_MUL(beta, delta);
-
-	g->average_agg = MIRA_FP_MUL(MIRA_FP_1 - alpha, g->average_agg);
-	g->average_agg += MIRA_FP_MUL(alpha, agglen);
-
-	toverhead = ieee80211_mira_toverhead(mn, ic, ni);
-	toverhead = MIRA_FP_MUL(toverhead, rate);
-	g->measured = MIRA_FP_DIV(MIRA_FP_1 - sfer, MIRA_FP_1 +
-	    MIRA_FP_DIV(toverhead, MIRA_FP_MUL(ampdu_size, g->average_agg)));
-	g->measured = MIRA_FP_MUL(g->measured, rate);
 }
 
 void