| /* |
| * Copyright 2010 Hauke Mehrtens <hauke@hauke-m.de> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * Compatibility file for Linux wireless for kernels 2.6.38. |
| */ |
| |
| #include <linux/compat.h> |
| #include <linux/module.h> |
| #include <linux/bug.h> |
| |
| /** |
| * ewma_init() - Initialize EWMA parameters |
| * @avg: Average structure |
| * @factor: Factor to use for the scaled up internal value. The maximum value |
| * of averages can be ULONG_MAX/(factor*weight). |
| * @weight: Exponential weight, or decay rate. This defines how fast the |
| * influence of older values decreases. Has to be bigger than 1. |
| * |
| * Initialize the EWMA parameters for a given struct ewma @avg. |
| */ |
| void ewma_init(struct ewma *avg, unsigned long factor, unsigned long weight) |
| { |
| WARN_ON(weight <= 1 || factor == 0); |
| avg->internal = 0; |
| avg->weight = weight; |
| avg->factor = factor; |
| } |
| EXPORT_SYMBOL(ewma_init); |
| |
| /** |
| * ewma_add() - Exponentially weighted moving average (EWMA) |
| * @avg: Average structure |
| * @val: Current value |
| * |
| * Add a sample to the average. |
| */ |
| struct ewma *ewma_add(struct ewma *avg, unsigned long val) |
| { |
| avg->internal = avg->internal ? |
| (((avg->internal * (avg->weight - 1)) + |
| (val * avg->factor)) / avg->weight) : |
| (val * avg->factor); |
| return avg; |
| } |
| EXPORT_SYMBOL(ewma_add); |
| |