summary refs log tree commit diff
path: root/net/mac80211
diff options
context:
space:
mode:
authorKarl Beldan <karl.beldan@rivierawaves.com>2013-04-17 13:43:22 +0200
committerJohannes Berg <johannes.berg@intel.com>2013-04-17 17:08:49 +0200
commiteea85999eca4d7f3528010cd8277392cd56ba713 (patch)
treeca7ab112a1767ce31a3d6ea5ac9e7c82a4db9343 /net/mac80211
parente1c3b15dd33a7d990188fa5b4731c78f8ba416a4 (diff)
downloadlinux-eea85999eca4d7f3528010cd8277392cd56ba713.tar.gz
mac80211: optimize minstrel_ewma
Use powers of two in ewma of minstrel.
This changes :
- EWMA_DIV   from 100 to 2^7
- EWMA_LEVEL from 75 (/EWMA_DIV=100) to 2^6 + 2^5 (/EWMA_DIV=128)

Note that this changes EWMA_DIV - EWMA_LEVEL from 25 to 2^5 and keeps
EWMA_LEVEL / EWMA_DIV == 0.75.

Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211')
-rw-r--r--net/mac80211/rc80211_minstrel.h5
1 files changed, 3 insertions, 2 deletions
diff --git a/net/mac80211/rc80211_minstrel.h b/net/mac80211/rc80211_minstrel.h
index 85ebf42cb46d..b9f8535fa15c 100644
--- a/net/mac80211/rc80211_minstrel.h
+++ b/net/mac80211/rc80211_minstrel.h
@@ -9,7 +9,8 @@
 #ifndef __RC_MINSTREL_H
 #define __RC_MINSTREL_H
 
-#define EWMA_LEVEL	75	/* ewma weighting factor [%] */
+#define EWMA_LEVEL	96	/* ewma weighting factor [/EWMA_DIV] */
+#define EWMA_DIV	128
 #define SAMPLE_COLUMNS	10	/* number of columns in sample table */
 
 
@@ -27,7 +28,7 @@
 static inline int
 minstrel_ewma(int old, int new, int weight)
 {
-	return (new * (100 - weight) + old * weight) / 100;
+	return (new * (EWMA_DIV - weight) + old * weight) / EWMA_DIV;
 }