rte_sched_common.h revision 6b3e017e
1/*-
2 *   BSD LICENSE
3 *
4 *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
5 *   All rights reserved.
6 *
7 *   Redistribution and use in source and binary forms, with or without
8 *   modification, are permitted provided that the following conditions
9 *   are met:
10 *
11 *     * Redistributions of source code must retain the above copyright
12 *       notice, this list of conditions and the following disclaimer.
13 *     * Redistributions in binary form must reproduce the above copyright
14 *       notice, this list of conditions and the following disclaimer in
15 *       the documentation and/or other materials provided with the
16 *       distribution.
17 *     * Neither the name of Intel Corporation nor the names of its
18 *       contributors may be used to endorse or promote products derived
19 *       from this software without specific prior written permission.
20 *
21 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#ifndef __INCLUDE_RTE_SCHED_COMMON_H__
35#define __INCLUDE_RTE_SCHED_COMMON_H__
36
37#ifdef __cplusplus
38extern "C" {
39#endif
40
41#include <stdint.h>
42#include <sys/types.h>
43
44#define __rte_aligned_16 __attribute__((__aligned__(16)))
45
46static inline uint32_t
47rte_sched_min_val_2_u32(uint32_t x, uint32_t y)
48{
49	return (x < y)? x : y;
50}
51
52#if 0
53static inline uint32_t
54rte_min_pos_4_u16(uint16_t *x)
55{
56	uint32_t pos0, pos1;
57
58	pos0 = (x[0] <= x[1])? 0 : 1;
59	pos1 = (x[2] <= x[3])? 2 : 3;
60
61	return (x[pos0] <= x[pos1])? pos0 : pos1;
62}
63
64#else
65
66/* simplified version to remove branches with CMOV instruction */
67static inline uint32_t
68rte_min_pos_4_u16(uint16_t *x)
69{
70	uint32_t pos0 = 0;
71	uint32_t pos1 = 2;
72
73	if (x[1] <= x[0]) pos0 = 1;
74	if (x[3] <= x[2]) pos1 = 3;
75	if (x[pos1] <= x[pos0]) pos0 = pos1;
76
77	return pos0;
78}
79
80#endif
81
82/*
83 * Compute the Greatest Common Divisor (GCD) of two numbers.
84 * This implementation uses Euclid's algorithm:
85 *    gcd(a, 0) = a
86 *    gcd(a, b) = gcd(b, a mod b)
87 *
88 */
89static inline uint32_t
90rte_get_gcd(uint32_t a, uint32_t b)
91{
92	uint32_t c;
93
94	if (a == 0)
95		return b;
96	if (b == 0)
97		return a;
98
99	if (a < b) {
100		c = a;
101		a = b;
102		b = c;
103	}
104
105	while (b != 0) {
106		c = a % b;
107		a = b;
108		b = c;
109	}
110
111	return a;
112}
113
114/*
115 * Compute the Lowest Common Denominator (LCD) of two numbers.
116 * This implementation computes GCD first:
117 *    LCD(a, b) = (a * b) / GCD(a, b)
118 *
119 */
120static inline uint32_t
121rte_get_lcd(uint32_t a, uint32_t b)
122{
123	return (a * b) / rte_get_gcd(a, b);
124}
125
126#ifdef __cplusplus
127}
128#endif
129
130#endif /* __INCLUDE_RTE_SCHED_COMMON_H__ */
131