ceph/src/dpdk/lib/librte_sched/rte_sched_common.h

   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
  38 extern "C" {
  39 #endif
  40
  41 #include <stdint.h>
  42 #include <sys/types.h>
  43
  44 #define __rte_aligned_16 __attribute__((__aligned__(16)))
  45
  46 static inline uint32_t
  47 rte_sched_min_val_2_u32(uint32_t x, uint32_t y)
  48 {
  49         return (x < y)? x : y;
  50 }
  51
  52 #if 0
  53 static inline uint32_t
  54 rte_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 */
  67 static inline uint32_t
  68 rte_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  */
  89 static inline uint32_t
  90 rte_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  */
 120 static inline uint32_t
 121 rte_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__ */