| Bruno Randolf | c5485a7 | 2010-11-16 10:58:37 +0900 | [diff] [blame] | 1 | #ifndef _LINUX_AVERAGE_H |
| 2 | #define _LINUX_AVERAGE_H |
| 3 | |
| Bruno Randolf | c5485a7 | 2010-11-16 10:58:37 +0900 | [diff] [blame] | 4 | /* Exponentially weighted moving average (EWMA) */ |
| 5 | |
| Johannes Berg | 2377799 | 2015-07-13 12:17:25 +0200 | [diff] [blame] | 6 | #define DECLARE_EWMA(name, _factor, _weight) \ |
| 7 | struct ewma_##name { \ |
| 8 | unsigned long internal; \ |
| 9 | }; \ |
| 10 | static inline void ewma_##name##_init(struct ewma_##name *e) \ |
| 11 | { \ |
| 12 | BUILD_BUG_ON(!__builtin_constant_p(_factor)); \ |
| 13 | BUILD_BUG_ON(!__builtin_constant_p(_weight)); \ |
| 14 | BUILD_BUG_ON_NOT_POWER_OF_2(_factor); \ |
| 15 | BUILD_BUG_ON_NOT_POWER_OF_2(_weight); \ |
| 16 | e->internal = 0; \ |
| 17 | } \ |
| 18 | static inline unsigned long \ |
| 19 | ewma_##name##_read(struct ewma_##name *e) \ |
| 20 | { \ |
| 21 | BUILD_BUG_ON(!__builtin_constant_p(_factor)); \ |
| 22 | BUILD_BUG_ON(!__builtin_constant_p(_weight)); \ |
| 23 | BUILD_BUG_ON_NOT_POWER_OF_2(_factor); \ |
| 24 | BUILD_BUG_ON_NOT_POWER_OF_2(_weight); \ |
| 25 | return e->internal >> ilog2(_factor); \ |
| 26 | } \ |
| 27 | static inline void ewma_##name##_add(struct ewma_##name *e, \ |
| 28 | unsigned long val) \ |
| 29 | { \ |
| 30 | unsigned long internal = ACCESS_ONCE(e->internal); \ |
| 31 | unsigned long weight = ilog2(_weight); \ |
| 32 | unsigned long factor = ilog2(_factor); \ |
| 33 | \ |
| 34 | BUILD_BUG_ON(!__builtin_constant_p(_factor)); \ |
| 35 | BUILD_BUG_ON(!__builtin_constant_p(_weight)); \ |
| 36 | BUILD_BUG_ON_NOT_POWER_OF_2(_factor); \ |
| 37 | BUILD_BUG_ON_NOT_POWER_OF_2(_weight); \ |
| 38 | \ |
| 39 | ACCESS_ONCE(e->internal) = internal ? \ |
| 40 | (((internal << weight) - internal) + \ |
| 41 | (val << factor)) >> weight : \ |
| 42 | (val << factor); \ |
| 43 | } |
| 44 | |
| Bruno Randolf | c5485a7 | 2010-11-16 10:58:37 +0900 | [diff] [blame] | 45 | #endif /* _LINUX_AVERAGE_H */ |