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

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2014 Intel Corporation
   3  */
   4
   5 #ifndef __INCLUDE_RTE_SCHED_COMMON_H__
   6 #define __INCLUDE_RTE_SCHED_COMMON_H__
   7
   8 #ifdef __cplusplus
   9 extern "C" {
  10 #endif
  11
  12 #include <stdint.h>
  13 #include <sys/types.h>
  14
  15 #define __rte_aligned_16 __attribute__((__aligned__(16)))
  16
  17 static inline uint32_t
  18 rte_sched_min_val_2_u32(uint32_t x, uint32_t y)
  19 {
  20         return (x < y)? x : y;
  21 }
  22
  23 #if 0
  24 static inline uint32_t
  25 rte_min_pos_4_u16(uint16_t *x)
  26 {
  27         uint32_t pos0, pos1;
  28
  29         pos0 = (x[0] <= x[1])? 0 : 1;
  30         pos1 = (x[2] <= x[3])? 2 : 3;
  31
  32         return (x[pos0] <= x[pos1])? pos0 : pos1;
  33 }
  34
  35 #else
  36
  37 /* simplified version to remove branches with CMOV instruction */
  38 static inline uint32_t
  39 rte_min_pos_4_u16(uint16_t *x)
  40 {
  41         uint32_t pos0 = 0;
  42         uint32_t pos1 = 2;
  43
  44         if (x[1] <= x[0]) pos0 = 1;
  45         if (x[3] <= x[2]) pos1 = 3;
  46         if (x[pos1] <= x[pos0]) pos0 = pos1;
  47
  48         return pos0;
  49 }
  50
  51 #endif
  52
  53 /*
  54  * Compute the Greatest Common Divisor (GCD) of two numbers.
  55  * This implementation uses Euclid's algorithm:
  56  *    gcd(a, 0) = a
  57  *    gcd(a, b) = gcd(b, a mod b)
  58  *
  59  */
  60 static inline uint32_t
  61 rte_get_gcd(uint32_t a, uint32_t b)
  62 {
  63         uint32_t c;
  64
  65         if (a == 0)
  66                 return b;
  67         if (b == 0)
  68                 return a;
  69
  70         if (a < b) {
  71                 c = a;
  72                 a = b;
  73                 b = c;
  74         }
  75
  76         while (b != 0) {
  77                 c = a % b;
  78                 a = b;
  79                 b = c;
  80         }
  81
  82         return a;
  83 }
  84
  85 /*
  86  * Compute the Lowest Common Denominator (LCD) of two numbers.
  87  * This implementation computes GCD first:
  88  *    LCD(a, b) = (a * b) / GCD(a, b)
  89  *
  90  */
  91 static inline uint32_t
  92 rte_get_lcd(uint32_t a, uint32_t b)
  93 {
  94         return (a * b) / rte_get_gcd(a, b);
  95 }
  96
  97 #ifdef __cplusplus
  98 }
  99 #endif
 100
 101 #endif /* __INCLUDE_RTE_SCHED_COMMON_H__ */