1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
|
/* $NetBSD: average.h,v 1.2 2021/12/19 10:38:38 riastradh Exp $ */
/*-
* Copyright (c) 2020 The NetBSD Foundation, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _LINUX_AVERAGE_H_
#define _LINUX_AVERAGE_H_
#define DECLARE_EWMA(NAME, PREC, RATE) \
struct ewma_##NAME { \
unsigned long ewma_state; \
}; \
\
static inline void \
ewma_##NAME##_init(struct ewma_##NAME *ewma) \
{ \
ewma->ewma_state = 0; \
} \
\
static inline unsigned long \
ewma_##NAME##_read(struct ewma_##NAME *ewma) \
{ \
return ewma->ewma_state >> (PREC); \
} \
\
static inline void \
ewma_##NAME##_add(struct ewma_##NAME *ewma, unsigned long sample) \
{ \
const unsigned long shift = ilog2(RATE); \
const unsigned long state = ewma->ewma_state; \
\
sample <<= (PREC); \
if (state == 0) { \
ewma->ewma_state = sample; \
return; \
} \
ewma->ewma_state = (((state << shift) - state) + sample) >> shift; \
}
#endif /* _LINUX_AVERAGE_H_ */
|