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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 | #include <math.h> | |
35 | #include "rte_red.h" | |
36 | #include <rte_random.h> | |
37 | #include <rte_common.h> | |
38 | ||
39 | #ifdef __INTEL_COMPILER | |
40 | #pragma warning(disable:2259) /* conversion may lose significant bits */ | |
41 | #endif | |
42 | ||
43 | static int rte_red_init_done = 0; /**< Flag to indicate that global initialisation is done */ | |
44 | uint32_t rte_red_rand_val = 0; /**< Random value cache */ | |
45 | uint32_t rte_red_rand_seed = 0; /**< Seed for random number generation */ | |
46 | ||
47 | /** | |
48 | * table[i] = log2(1-Wq) * Scale * -1 | |
49 | * Wq = 1/(2^i) | |
50 | */ | |
51 | uint16_t rte_red_log2_1_minus_Wq[RTE_RED_WQ_LOG2_NUM]; | |
52 | ||
53 | /** | |
54 | * table[i] = 2^(i/16) * Scale | |
55 | */ | |
56 | uint16_t rte_red_pow2_frac_inv[16]; | |
57 | ||
58 | /** | |
59 | * @brief Initialize tables used to compute average | |
60 | * queue size when queue is empty. | |
61 | */ | |
62 | static void | |
63 | __rte_red_init_tables(void) | |
64 | { | |
65 | uint32_t i = 0; | |
66 | double scale = 0.0; | |
67 | double table_size = 0.0; | |
68 | ||
69 | scale = (double)(1 << RTE_RED_SCALING); | |
70 | table_size = (double)(RTE_DIM(rte_red_pow2_frac_inv)); | |
71 | ||
72 | for (i = 0; i < RTE_DIM(rte_red_pow2_frac_inv); i++) { | |
73 | double m = (double)i; | |
74 | ||
75 | rte_red_pow2_frac_inv[i] = (uint16_t) round(scale / pow(2, m / table_size)); | |
76 | } | |
77 | ||
78 | scale = 1024.0; | |
79 | ||
80 | RTE_ASSERT(RTE_RED_WQ_LOG2_NUM == RTE_DIM(rte_red_log2_1_minus_Wq)); | |
81 | ||
82 | for (i = RTE_RED_WQ_LOG2_MIN; i <= RTE_RED_WQ_LOG2_MAX; i++) { | |
83 | double n = (double)i; | |
84 | double Wq = pow(2, -n); | |
85 | uint32_t index = i - RTE_RED_WQ_LOG2_MIN; | |
86 | ||
87 | rte_red_log2_1_minus_Wq[index] = (uint16_t) round(-1.0 * scale * log2(1.0 - Wq)); | |
88 | /** | |
89 | * Table entry of zero, corresponds to a Wq of zero | |
90 | * which is not valid (avg would remain constant no | |
91 | * matter how long the queue is empty). So we have | |
92 | * to check for zero and round up to one. | |
93 | */ | |
94 | if (rte_red_log2_1_minus_Wq[index] == 0) { | |
95 | rte_red_log2_1_minus_Wq[index] = 1; | |
96 | } | |
97 | } | |
98 | } | |
99 | ||
100 | int | |
101 | rte_red_rt_data_init(struct rte_red *red) | |
102 | { | |
103 | if (red == NULL) | |
104 | return -1; | |
105 | ||
106 | red->avg = 0; | |
107 | red->count = 0; | |
108 | red->q_time = 0; | |
109 | return 0; | |
110 | } | |
111 | ||
112 | int | |
113 | rte_red_config_init(struct rte_red_config *red_cfg, | |
114 | const uint16_t wq_log2, | |
115 | const uint16_t min_th, | |
116 | const uint16_t max_th, | |
117 | const uint16_t maxp_inv) | |
118 | { | |
119 | if (red_cfg == NULL) { | |
120 | return -1; | |
121 | } | |
122 | if (max_th > RTE_RED_MAX_TH_MAX) { | |
123 | return -2; | |
124 | } | |
125 | if (min_th >= max_th) { | |
126 | return -3; | |
127 | } | |
128 | if (wq_log2 > RTE_RED_WQ_LOG2_MAX) { | |
129 | return -4; | |
130 | } | |
131 | if (wq_log2 < RTE_RED_WQ_LOG2_MIN) { | |
132 | return -5; | |
133 | } | |
134 | if (maxp_inv < RTE_RED_MAXP_INV_MIN) { | |
135 | return -6; | |
136 | } | |
137 | if (maxp_inv > RTE_RED_MAXP_INV_MAX) { | |
138 | return -7; | |
139 | } | |
140 | ||
141 | /** | |
142 | * Initialize the RED module if not already done | |
143 | */ | |
144 | if (!rte_red_init_done) { | |
145 | rte_red_rand_seed = rte_rand(); | |
146 | rte_red_rand_val = rte_fast_rand(); | |
147 | __rte_red_init_tables(); | |
148 | rte_red_init_done = 1; | |
149 | } | |
150 | ||
151 | red_cfg->min_th = ((uint32_t) min_th) << (wq_log2 + RTE_RED_SCALING); | |
152 | red_cfg->max_th = ((uint32_t) max_th) << (wq_log2 + RTE_RED_SCALING); | |
153 | red_cfg->pa_const = (2 * (max_th - min_th) * maxp_inv) << RTE_RED_SCALING; | |
154 | red_cfg->maxp_inv = maxp_inv; | |
155 | red_cfg->wq_log2 = wq_log2; | |
156 | ||
157 | return 0; | |
158 | } |