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af55688435
Using bitshifts instead of division and multiplication should improve performance. That requires weight and factor to be powers of two, but i think this is something we can live with. Thanks to Peter Zijlstra for the improved formula! Signed-off-by: Bruno Randolf <br1@einfach.org> -- v2: use log2.h functions Signed-off-by: John W. Linville <linville@tuxdriver.com>
31 lines
653 B
C
31 lines
653 B
C
#ifndef _LINUX_AVERAGE_H
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#define _LINUX_AVERAGE_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 avg->internal >> avg->factor;
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}
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#endif /* _LINUX_AVERAGE_H */
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