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36 #include <rte_random.h>
38 #ifdef __INTEL_COMPILER
39 #pragma warning(disable:2259) /* conversion may lose significant bits */
42 #define DIM(x) (sizeof(x)/sizeof(x[0]))
44 static int rte_red_init_done = 0; /**< Flag to indicate that global initialisation is done */
45 uint32_t rte_red_rand_val = 0; /**< Random value cache */
46 uint32_t rte_red_rand_seed = 0; /**< Seed for random number generation */
49 * table[i] = log2(1-Wq) * Scale * -1
52 uint16_t rte_red_log2_1_minus_Wq[RTE_RED_WQ_LOG2_NUM];
55 * table[i] = 2^(i/16) * Scale
57 uint16_t rte_red_pow2_frac_inv[16];
60 * @brief Initialize tables used to compute average
61 * queue size when queue is empty.
64 __rte_red_init_tables(void)
68 double table_size = 0.0;
70 scale = (double)(1 << RTE_RED_SCALING);
71 table_size = (double)(DIM(rte_red_pow2_frac_inv));
73 for (i = 0; i < DIM(rte_red_pow2_frac_inv); i++) {
76 rte_red_pow2_frac_inv[i] = (uint16_t) round(scale / pow(2, m / table_size));
81 RTE_RED_ASSERT(RTE_RED_WQ_LOG2_NUM == DIM(rte_red_log2_1_minus_Wq));
83 for (i = RTE_RED_WQ_LOG2_MIN; i <= RTE_RED_WQ_LOG2_MAX; i++) {
85 double Wq = pow(2, -n);
86 uint32_t index = i - RTE_RED_WQ_LOG2_MIN;
88 rte_red_log2_1_minus_Wq[index] = (uint16_t) round(-1.0 * scale * log2(1.0 - Wq));
90 * Table entry of zero, corresponds to a Wq of zero
91 * which is not valid (avg would remain constant no
92 * matter how long the queue is empty). So we have
93 * to check for zero and round up to one.
95 if (rte_red_log2_1_minus_Wq[index] == 0) {
96 rte_red_log2_1_minus_Wq[index] = 1;
102 rte_red_rt_data_init(struct rte_red *red)
114 rte_red_config_init(struct rte_red_config *red_cfg,
115 const uint16_t wq_log2,
116 const uint16_t min_th,
117 const uint16_t max_th,
118 const uint16_t maxp_inv)
120 if (red_cfg == NULL) {
123 if (max_th > RTE_RED_MAX_TH_MAX) {
126 if (min_th >= max_th) {
129 if (wq_log2 > RTE_RED_WQ_LOG2_MAX) {
132 if (wq_log2 < RTE_RED_WQ_LOG2_MIN) {
135 if (maxp_inv < RTE_RED_MAXP_INV_MIN) {
138 if (maxp_inv > RTE_RED_MAXP_INV_MAX) {
143 * Initialize the RED module if not already done
145 if (!rte_red_init_done) {
146 rte_red_rand_seed = rte_rand();
147 rte_red_rand_val = rte_fast_rand();
148 __rte_red_init_tables();
149 rte_red_init_done = 1;
152 red_cfg->min_th = ((uint32_t) min_th) << (wq_log2 + RTE_RED_SCALING);
153 red_cfg->max_th = ((uint32_t) max_th) << (wq_log2 + RTE_RED_SCALING);
154 red_cfg->pa_const = (2 * (max_th - min_th) * maxp_inv) << RTE_RED_SCALING;
155 red_cfg->maxp_inv = maxp_inv;
156 red_cfg->wq_log2 = wq_log2;