Imported Upstream version 16.04

[deb_dpdk.git] / lib / librte_sched / rte_red.c

diff --git a/lib/librte_sched/rte_red.c b/lib/librte_sched/rte_red.c
new file mode 100644 (file)
index 0000000..fdf4057
--- /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;
+}