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Diffstat (limited to 'lib/librte_sched/rte_red.c')
| -rw-r--r-- | lib/librte_sched/rte_red.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/lib/librte_sched/rte_red.c b/lib/librte_sched/rte_red.c new file mode 100644 index 00000000..fdf40576 --- /dev/null +++ b/lib/librte_sched/rte_red.c @@ -0,0 +1,158 @@ +/*- + * 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; +} |