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c5485a7e75
This adds generic functions for calculating Exponentially Weighted Moving Averages (EWMA). This implementation makes use of a structure which keeps the EWMA parameters and a scaled up internal representation to reduce rounding errors. The original idea for this implementation came from the rt2x00 driver (rt2x00link.c). I would like to use it in several places in the mac80211 and ath5k code and I hope it can be useful in many other places in the kernel code. Signed-off-by: Bruno Randolf <br1@einfach.org> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
33 lines
697 B
C
33 lines
697 B
C
#ifndef _LINUX_AVERAGE_H
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#define _LINUX_AVERAGE_H
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#include <linux/kernel.h>
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/* Exponentially weighted moving average (EWMA) */
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/* For more documentation see lib/average.c */
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struct ewma {
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unsigned long internal;
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unsigned long factor;
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unsigned long weight;
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};
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extern void ewma_init(struct ewma *avg, unsigned long factor,
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unsigned long weight);
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extern struct ewma *ewma_add(struct ewma *avg, unsigned long val);
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/**
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* ewma_read() - Get average value
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* @avg: Average structure
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*
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* Returns the average value held in @avg.
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*/
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static inline unsigned long ewma_read(const struct ewma *avg)
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{
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return DIV_ROUND_CLOSEST(avg->internal, avg->factor);
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}
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#endif /* _LINUX_AVERAGE_H */
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