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/*-
* BSD LICENSE
*
* Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <math.h>
#include "rte_red.h"
#include <rte_random.h>
#include <rte_common.h>
#ifdef __INTEL_COMPILER
#pragma warning(disable:2259) /* conversion may lose significant bits */
#endif
static int rte_red_init_done = 0; /**< Flag to indicate that global initialisation is done */
uint32_t rte_red_rand_val = 0; /**< Random value cache */
uint32_t rte_red_rand_seed = 0; /**< Seed for random number generation */
/**
* table[i] = log2(1-Wq) * Scale * -1
* Wq = 1/(2^i)
*/
uint16_t rte_red_log2_1_minus_Wq[RTE_RED_WQ_LOG2_NUM];
/**
* table[i] = 2^(i/16) * Scale
*/
uint16_t rte_red_pow2_frac_inv[16];
/**
* @brief Initialize tables used to compute average
* queue size when queue is empty.
*/
static void
__rte_red_init_tables(void)
{
uint32_t i = 0;
double scale = 0.0;
double table_size = 0.0;
scale = (double)(1 << RTE_RED_SCALING);
table_size = (double)(RTE_DIM(rte_red_pow2_frac_inv));
for (i = 0; i < RTE_DIM(rte_red_pow2_frac_inv); i++) {
double m = (double)i;
rte_red_pow2_frac_inv[i] = (uint16_t) round(scale / pow(2, m / table_size));
}
scale = 1024.0;
RTE_RED_ASSERT(RTE_RED_WQ_LOG2_NUM == RTE_DIM(rte_red_log2_1_minus_Wq));
for (i = RTE_RED_WQ_LOG2_MIN; i <= RTE_RED_WQ_LOG2_MAX; i++) {
double n = (double)i;
double Wq = pow(2, -n);
uint32_t index = i - RTE_RED_WQ_LOG2_MIN;
rte_red_log2_1_minus_Wq[index] = (uint16_t) round(-1.0 * scale * log2(1.0 - Wq));
/**
* Table entry of zero, corresponds to a Wq of zero
* which is not valid (avg would remain constant no
* matter how long the queue is empty). So we have
* to check for zero and round up to one.
*/
if (rte_red_log2_1_minus_Wq[index] == 0) {
rte_red_log2_1_minus_Wq[index] = 1;
}
}
}
int
rte_red_rt_data_init(struct rte_red *red)
{
if (red == NULL)
return -1;
red->avg = 0;
red->count = 0;
red->q_time = 0;
return 0;
}
int
rte_red_config_init(struct rte_red_config *red_cfg,
const uint16_t wq_log2,
const uint16_t min_th,
const uint16_t max_th,
const uint16_t maxp_inv)
{
if (red_cfg == NULL) {
return -1;
}
if (max_th > RTE_RED_MAX_TH_MAX) {
return -2;
}
if (min_th >= max_th) {
return -3;
}
if (wq_log2 > RTE_RED_WQ_LOG2_MAX) {
return -4;
}
if (wq_log2 < RTE_RED_WQ_LOG2_MIN) {
return -5;
}
if (maxp_inv < RTE_RED_MAXP_INV_MIN) {
return -6;
}
if (maxp_inv > RTE_RED_MAXP_INV_MAX) {
return -7;
}
/**
* Initialize the RED module if not already done
*/
if (!rte_red_init_done) {
rte_red_rand_seed = rte_rand();
rte_red_rand_val = rte_fast_rand();
__rte_red_init_tables();
rte_red_init_done = 1;
}
red_cfg->min_th = ((uint32_t) min_th) << (wq_log2 + RTE_RED_SCALING);
red_cfg->max_th = ((uint32_t) max_th) << (wq_log2 + RTE_RED_SCALING);
red_cfg->pa_const = (2 * (max_th - min_th) * maxp_inv) << RTE_RED_SCALING;
red_cfg->maxp_inv = maxp_inv;
red_cfg->wq_log2 = wq_log2;
return 0;
}
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