Commit eea85999 authored Apr 17, 2013 by Karl Beldan Committed by Johannes Berg Apr 17, 2013

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>

parent e1c3b15d

net/mac80211/rc80211_minstrel.h

+3 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}

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