Implement PIE based congestion management based on rfc8033

Signed-off-by: Liguzinski, WojciechX <wojciechx.liguzin...@intel.com>
---
 drivers/net/softnic/rte_eth_softnic_tm.c |   6 +-
 lib/sched/meson.build                    |  10 +-
 lib/sched/rte_pie.c                      |  82 +++++
 lib/sched/rte_pie.h                      | 393 +++++++++++++++++++++++
 lib/sched/rte_sched.c                    | 228 +++++++++----
 lib/sched/rte_sched.h                    |  53 ++-
 lib/sched/version.map                    |   3 +
 7 files changed, 685 insertions(+), 90 deletions(-)
 create mode 100644 lib/sched/rte_pie.c
 create mode 100644 lib/sched/rte_pie.h

diff --git a/drivers/net/softnic/rte_eth_softnic_tm.c 
b/drivers/net/softnic/rte_eth_softnic_tm.c
index 90baba15ce..5b6c4e6d4b 100644
--- a/drivers/net/softnic/rte_eth_softnic_tm.c
+++ b/drivers/net/softnic/rte_eth_softnic_tm.c
@@ -420,7 +420,7 @@ pmd_tm_node_type_get(struct rte_eth_dev *dev,
        return 0;
 }
 
-#ifdef RTE_SCHED_RED
+#ifdef RTE_SCHED_AQM
 #define WRED_SUPPORTED                                         1
 #else
 #define WRED_SUPPORTED                                         0
@@ -2306,7 +2306,7 @@ tm_tc_wred_profile_get(struct rte_eth_dev *dev, uint32_t 
tc_id)
        return NULL;
 }
 
-#ifdef RTE_SCHED_RED
+#ifdef RTE_SCHED_AQM
 
 static void
 wred_profiles_set(struct rte_eth_dev *dev, uint32_t subport_id)
@@ -2321,7 +2321,7 @@ wred_profiles_set(struct rte_eth_dev *dev, uint32_t 
subport_id)
        for (tc_id = 0; tc_id < RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE; tc_id++)
                for (color = RTE_COLOR_GREEN; color < RTE_COLORS; color++) {
                        struct rte_red_params *dst =
-                               &pp->red_params[tc_id][color];
+                               &pp->wred_params[tc_id][color];
                        struct tm_wred_profile *src_wp =
                                tm_tc_wred_profile_get(dev, tc_id);
                        struct rte_tm_red_params *src =
diff --git a/lib/sched/meson.build b/lib/sched/meson.build
index b24f7b8775..e7ae9bcf19 100644
--- a/lib/sched/meson.build
+++ b/lib/sched/meson.build
@@ -1,11 +1,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2017 Intel Corporation
 
-sources = files('rte_sched.c', 'rte_red.c', 'rte_approx.c')
-headers = files(
-        'rte_approx.h',
-        'rte_red.h',
-        'rte_sched.h',
-        'rte_sched_common.h',
-)
+sources = files('rte_sched.c', 'rte_red.c', 'rte_approx.c', 'rte_pie.c')
+headers = files('rte_sched.h', 'rte_sched_common.h',
+               'rte_red.h', 'rte_approx.h', 'rte_pie.h')
 deps += ['mbuf', 'meter']
diff --git a/lib/sched/rte_pie.c b/lib/sched/rte_pie.c
new file mode 100644
index 0000000000..2fcecb2db4
--- /dev/null
+++ b/lib/sched/rte_pie.c
@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2020 Intel Corporation
+ */
+
+#include <stdlib.h>
+
+#include "rte_pie.h"
+#include <rte_common.h>
+#include <rte_cycles.h>
+#include <rte_malloc.h>
+
+#ifdef __INTEL_COMPILER
+#pragma warning(disable:2259) /* conversion may lose significant bits */
+#endif
+
+void
+rte_pie_rt_data_init(struct rte_pie *pie)
+{
+       if (pie == NULL) {
+               /* Allocate memory to use the PIE data structure */
+               pie = rte_malloc(NULL, sizeof(struct rte_pie), 0);
+
+               if (pie == NULL)
+                       RTE_LOG(ERR, SCHED, "%s: Memory allocation fails\n", 
__func__);
+       }
+
+       pie->active = 0;
+       pie->in_measurement = 0;
+       pie->departed_bytes_count = 0;
+       pie->start_measurement = 0;
+       pie->last_measurement = 0;
+       pie->qlen = 0;
+       pie->avg_dq_time = 0;
+       pie->burst_allowance = 0;
+       pie->qdelay_old = 0;
+       pie->drop_prob = 0;
+       pie->accu_prob = 0;
+}
+
+int
+rte_pie_config_init(struct rte_pie_config *pie_cfg,
+       const uint16_t qdelay_ref,
+       const uint16_t dp_update_interval,
+       const uint16_t max_burst,
+       const uint16_t tailq_th)
+{
+       uint64_t tsc_hz = rte_get_tsc_hz();
+
+       if (pie_cfg == NULL)
+               return -1;
+
+       if (qdelay_ref <= 0) {
+               RTE_LOG(ERR, SCHED,
+                       "%s: Incorrect value for qdelay_ref\n", __func__);
+               return -EINVAL;
+       }
+
+       if (dp_update_interval <= 0) {
+               RTE_LOG(ERR, SCHED,
+                       "%s: Incorrect value for dp_update_interval\n", 
__func__);
+               return -EINVAL;
+       }
+
+       if (max_burst <= 0) {
+               RTE_LOG(ERR, SCHED,
+                       "%s: Incorrect value for max_burst\n", __func__);
+               return -EINVAL;
+       }
+
+       if (tailq_th <= 0) {
+               RTE_LOG(ERR, SCHED,
+                       "%s: Incorrect value for tailq_th\n", __func__);
+               return -EINVAL;
+       }
+
+       pie_cfg->qdelay_ref = (tsc_hz * qdelay_ref) / 1000;
+       pie_cfg->dp_update_interval = (tsc_hz * dp_update_interval) / 1000;
+       pie_cfg->max_burst = (tsc_hz * max_burst) / 1000;
+       pie_cfg->tailq_th = tailq_th;
+
+       return 0;
+}
diff --git a/lib/sched/rte_pie.h b/lib/sched/rte_pie.h
new file mode 100644
index 0000000000..f83c95664f
--- /dev/null
+++ b/lib/sched/rte_pie.h
@@ -0,0 +1,393 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2020 Intel Corporation
+ */
+
+#ifndef __RTE_PIE_H_INCLUDED__
+#define __RTE_PIE_H_INCLUDED__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @file
+ * RTE Proportional Integral controller Enhanced (PIE)
+ *
+ *
+ ***/
+
+#include <stdint.h>
+
+#include <rte_random.h>
+#include <rte_debug.h>
+
+#define RTE_DQ_THRESHOLD   16384   /**< Queue length threshold (2^14)
+                                    * to start measurement cycle (bytes)
+                                    */
+#define RTE_DQ_WEIGHT      0.25    /**< Weight (RTE_DQ_THRESHOLD/2^16) to 
compute dequeue rate */
+#define RTE_ALPHA          0.125   /**< Weights in drop probability 
calculations */
+#define RTE_BETA           1.25    /**< Weights in drop probability 
calculations */
+#define RTE_RAND_MAX      ~0LLU    /**< Max value of the random number */
+
+
+/**
+ * PIE configuration parameters passed by user
+ *
+ */
+struct rte_pie_params {
+       uint16_t qdelay_ref;           /**< Latency Target (milliseconds) */
+       uint16_t dp_update_interval;   /**< Update interval for drop 
probability (milliseconds) */
+       uint16_t max_burst;            /**< Max Burst Allowance (milliseconds) 
*/
+       uint16_t tailq_th;             /**< Tailq drop threshold (packet 
counts) */
+};
+
+/**
+ * PIE configuration parameters
+ *
+ */
+struct rte_pie_config {
+       uint64_t qdelay_ref;           /**< Latency Target (in CPU cycles.) */
+       uint64_t dp_update_interval;   /**< Update interval for drop 
probability (in CPU cycles) */
+       uint64_t max_burst;            /**< Max Burst Allowance (in CPU 
cycles.) */
+       uint16_t tailq_th;             /**< Tailq drop threshold (packet 
counts) */
+};
+
+/**
+ * RED run-time data
+ */
+struct rte_pie {
+       uint16_t active;               /**< Flag for activating/deactivating 
pie */
+       uint16_t in_measurement;       /**< Flag for activation of measurement 
cycle */
+       uint32_t departed_bytes_count; /**< Number of bytes departed in current 
measurement cycle */
+       uint64_t start_measurement;    /**< Time to start to measurement cycle 
(in cpu cycles) */
+       uint64_t last_measurement;     /**< Time of last measurement (in cpu 
cycles) */
+       uint64_t qlen;                 /**< Queue length (packets count) */
+       uint64_t qlen_bytes;           /**< Queue length (bytes count) */
+       uint64_t avg_dq_time;          /**< Time averaged dequeue rate (in cpu 
cycles) */
+       uint32_t burst_allowance;      /**< Current burst allowance (bytes) */
+       uint64_t qdelay_old;           /**< Old queue delay (bytes) */
+       double drop_prob;              /**< Current packet drop probability */
+       double accu_prob;              /**< Accumulated packet drop probability 
*/
+};
+
+/**
+ * @brief Initialises run-time data
+ *
+ * @param pie [in,out] data pointer to PIE runtime data
+ */
+void
+__rte_experimental
+rte_pie_rt_data_init(struct rte_pie *pie);
+
+/**
+ * @brief Configures a single PIE configuration parameter structure.
+ *
+ * @param pie_cfg [in,out] config pointer to a PIE configuration parameter 
structure
+ * @param qdelay_ref [in]  latency target(milliseconds)
+ * @param dp_update_interval [in] update interval for drop probability 
(milliseconds)
+ * @param max_burst [in] maximum burst allowance (milliseconds)
+ * @param tailq_th [in] tail drop threshold for the queue (number of packets)
+ *
+ * @return Operation status
+ * @retval 0 success
+ * @retval !0 error
+ */
+int
+__rte_experimental
+rte_pie_config_init(struct rte_pie_config *pie_cfg,
+       const uint16_t qdelay_ref,
+       const uint16_t dp_update_interval,
+       const uint16_t max_burst,
+       const uint16_t tailq_th);
+
+/**
+ * @brief Decides packet enqueue when queue is empty
+ *
+ * Note: packet is never dropped in this particular case.
+ *
+ * @param pie_cfg [in] config pointer to a PIE configuration parameter 
structure
+ * @param pie [in, out] data pointer to PIE runtime data
+ * @param pkt_len [in] packet length in bytes
+ *
+ * @return Operation status
+ * @retval 0 enqueue the packet
+ * @retval !0 drop the packet
+ */
+static inline int
+__rte_experimental
+rte_pie_enqueue_empty(const struct rte_pie_config *pie_cfg,
+       struct rte_pie *pie,
+       uint32_t pkt_len)
+{
+       RTE_ASSERT(pkt_len != NULL);
+
+       /* Update the PIE qlen parameter */
+       pie->qlen++;
+       pie->qlen_bytes += pkt_len;
+
+       /**
+        * If the queue has been idle for a while, turn off PIE and Reset 
counters
+        */
+       if ((pie->active == 1) &&
+               (pie->qlen < (pie_cfg->tailq_th * 0.1))) {
+               pie->active =  0;
+               pie->in_measurement = 0;
+       }
+
+       return 0;
+}
+
+/**
+ * @brief make a decision to drop or enqueue a packet based on probability
+ *        criteria
+ *
+ * @param pie_cfg [in] config pointer to a PIE configuration parameter 
structure
+ * @param pie [in, out] data pointer to PIE runtime data
+ * @param time [in] current time (measured in cpu cycles)
+ */
+static inline void
+__rte_experimental
+_calc_drop_probability(const struct rte_pie_config *pie_cfg,
+       struct rte_pie *pie, uint64_t time)
+{
+       uint64_t qdelay_ref = pie_cfg->qdelay_ref;
+
+       /* Note: can be implemented using integer multiply.
+        * DQ_THRESHOLD is power of 2 value.
+        */
+       double current_qdelay = pie->qlen * (pie->avg_dq_time / 
RTE_DQ_THRESHOLD);
+
+       double p = RTE_ALPHA * (current_qdelay - qdelay_ref) +
+               RTE_BETA * (current_qdelay - pie->qdelay_old);
+
+       if (pie->drop_prob < 0.000001)
+               p = p * 0.00048828125;              /* (1/2048) = 0.00048828125 
*/
+       else if (pie->drop_prob < 0.00001)
+               p = p * 0.001953125;                /* (1/512) = 0.001953125  */
+       else if (pie->drop_prob < 0.0001)
+               p = p * 0.0078125;                  /* (1/128) = 0.0078125  */
+       else if (pie->drop_prob < 0.001)
+               p = p * 0.03125;                    /* (1/32) = 0.03125   */
+       else if (pie->drop_prob < 0.01)
+               p = p * 0.125;                      /* (1/8) = 0.125    */
+       else if (pie->drop_prob < 0.1)
+               p = p * 0.5;                        /* (1/2) = 0.5    */
+
+       if (pie->drop_prob >= 0.1 && p > 0.02)
+               p = 0.02;
+
+       pie->drop_prob += p;
+
+       double qdelay = qdelay_ref * 0.5;
+
+       /*  Exponentially decay drop prob when congestion goes away  */
+       if (current_qdelay < qdelay && pie->qdelay_old < qdelay)
+               pie->drop_prob *= 0.98;     /* 1 - 1/64 is sufficient */
+
+       /* Bound drop probability */
+       if (pie->drop_prob < 0)
+               pie->drop_prob = 0;
+       if (pie->drop_prob > 1)
+               pie->drop_prob = 1;
+
+       pie->qdelay_old = current_qdelay;
+       pie->last_measurement = time;
+
+       uint64_t burst_allowance = pie->burst_allowance - 
pie_cfg->dp_update_interval;
+
+       pie->burst_allowance = (burst_allowance > 0) ? burst_allowance : 0;
+}
+
+/**
+ * @brief make a decision to drop or enqueue a packet based on probability
+ *        criteria
+ *
+ * @param pie_cfg [in] config pointer to a PIE configuration parameter 
structure
+ * @param pie [in, out] data pointer to PIE runtime data
+ *
+ * @return operation status
+ * @retval 0 enqueue the packet
+ * @retval 1 drop the packet
+ */
+static inline int
+__rte_experimental
+_rte_pie_drop(const struct rte_pie_config *pie_cfg,
+       struct rte_pie *pie)
+{
+       uint64_t rand_value;
+       double qdelay = pie_cfg->qdelay_ref * 0.5;
+
+       /* PIE is active but the queue is not congested: return 0 */
+       if (((pie->qdelay_old < qdelay) && (pie->drop_prob < 0.2)) ||
+               (pie->qlen <= (pie_cfg->tailq_th * 0.1)))
+               return 0;
+
+       if (pie->drop_prob == 0)
+               pie->accu_prob = 0;
+
+       /* For practical reasons, drop probability can be further scaled 
according
+        * to packet size, but one needs to set a bound to avoid unnecessary 
bias
+        * Random drop
+        */
+       pie->accu_prob += pie->drop_prob;
+
+       if (pie->accu_prob < 0.85)
+               return 0;
+
+       if (pie->accu_prob >= 8.5)
+               return 1;
+
+       rand_value = rte_rand()/RTE_RAND_MAX;
+
+       if ((double)rand_value < pie->drop_prob) {
+               pie->accu_prob = 0;
+               return 1;
+       }
+
+       /* No drop */
+       return 0;
+}
+
+/**
+ * @brief Decides if new packet should be enqeued or dropped for non-empty 
queue
+ *
+ * @param pie_cfg [in] config pointer to a PIE configuration parameter 
structure
+ * @param pie [in,out] data pointer to PIE runtime data
+ * @param pkt_len [in] packet length in bytes
+ * @param time [in] current time (measured in cpu cycles)
+ *
+ * @return Operation status
+ * @retval 0 enqueue the packet
+ * @retval 1 drop the packet based on max threshold criterion
+ * @retval 2 drop the packet based on mark probability criterion
+ */
+static inline int
+__rte_experimental
+rte_pie_enqueue_nonempty(const struct rte_pie_config *pie_cfg,
+       struct rte_pie *pie,
+       uint32_t pkt_len,
+       const uint64_t time)
+{
+       /* Check queue space against the tail drop threshold */
+       if (pie->qlen >= pie_cfg->tailq_th) {
+
+               pie->accu_prob = 0;
+               return 1;
+       }
+
+       if (pie->active) {
+               /* Update drop probability after certain interval */
+               if ((time - pie->last_measurement) >= 
pie_cfg->dp_update_interval)
+                       _calc_drop_probability(pie_cfg, pie, time);
+
+               /* Decide whether packet to be dropped or enqueued */
+               if (_rte_pie_drop(pie_cfg, pie) && pie->burst_allowance == 0)
+                       return 2;
+       }
+
+       /* When queue occupancy is over a certain threshold, turn on PIE */
+       if ((pie->active == 0) &&
+               (pie->qlen >= (pie_cfg->tailq_th * 0.1))) {
+               pie->active = 1;
+               pie->qdelay_old = 0;
+               pie->drop_prob = 0;
+               pie->in_measurement = 1;
+               pie->departed_bytes_count = 0;
+               pie->avg_dq_time = 0;
+               pie->last_measurement = time;
+               pie->burst_allowance = pie_cfg->max_burst;
+               pie->accu_prob = 0;
+               pie->start_measurement = time;
+       }
+
+       /* when queue has been idle for a while, turn off PIE and Reset 
counters */
+       if (pie->active == 1 &&
+               pie->qlen < (pie_cfg->tailq_th * 0.1)) {
+               pie->active =  0;
+               pie->in_measurement = 0;
+       }
+
+       /* Update PIE qlen parameter */
+       pie->qlen++;
+       pie->qlen_bytes += pkt_len;
+
+       /* No drop */
+       return 0;
+}
+
+/**
+ * @brief Decides if new packet should be enqeued or dropped
+ * Updates run time data and gives verdict whether to enqueue or drop the 
packet.
+ *
+ * @param pie_cfg [in] config pointer to a PIE configuration parameter 
structure
+ * @param pie [in,out] data pointer to PIE runtime data
+ * @param qlen [in] queue length
+ * @param pkt_len [in] packet length in bytes
+ * @param time [in] current time stamp (measured in cpu cycles)
+ *
+ * @return Operation status
+ * @retval 0 enqueue the packet
+ * @retval 1 drop the packet based on drop probility criteria
+ */
+static inline int
+__rte_experimental
+rte_pie_enqueue(const struct rte_pie_config *pie_cfg,
+       struct rte_pie *pie,
+       const unsigned int qlen,
+       uint32_t pkt_len,
+       const uint64_t time)
+{
+       RTE_ASSERT(pie_cfg != NULL);
+       RTE_ASSERT(pie != NULL);
+
+       if (qlen != 0)
+               return rte_pie_enqueue_nonempty(pie_cfg, pie, pkt_len, time);
+       else
+               return rte_pie_enqueue_empty(pie_cfg, pie, pkt_len);
+}
+
+/**
+ * @brief PIE rate estimation method
+ * Called on each packet departure.
+ *
+ * @param pie [in] data pointer to PIE runtime data
+ * @param pkt_len [in] packet length in bytes
+ * @param time [in] current time stamp in cpu cycles
+ */
+static inline void
+__rte_experimental
+rte_pie_dequeue(struct rte_pie *pie,
+       uint32_t pkt_len,
+       uint64_t time)
+{
+       /* Dequeue rate estimation */
+       if (pie->in_measurement) {
+               pie->departed_bytes_count += pkt_len;
+
+               /* Start a new measurement cycle when enough packets */
+               if (pie->departed_bytes_count >= RTE_DQ_THRESHOLD) {
+                       uint64_t dq_time = time - pie->start_measurement;
+
+                       if (pie->avg_dq_time == 0)
+                               pie->avg_dq_time = dq_time;
+                       else
+                               pie->avg_dq_time = dq_time * RTE_DQ_WEIGHT + 
pie->avg_dq_time
+                                       * (1 - RTE_DQ_WEIGHT);
+
+                       pie->in_measurement = 0;
+               }
+       }
+
+       /* Start measurement cycle when enough data in the queue */
+       if ((pie->qlen_bytes >= RTE_DQ_THRESHOLD) && (pie->in_measurement == 
0)) {
+               pie->in_measurement = 1;
+               pie->start_measurement = time;
+               pie->departed_bytes_count = 0;
+       }
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __RTE_PIE_H_INCLUDED__ */
diff --git a/lib/sched/rte_sched.c b/lib/sched/rte_sched.c
index a858f61f95..320435ed91 100644
--- a/lib/sched/rte_sched.c
+++ b/lib/sched/rte_sched.c
@@ -89,8 +89,12 @@ struct rte_sched_queue {
 
 struct rte_sched_queue_extra {
        struct rte_sched_queue_stats stats;
-#ifdef RTE_SCHED_RED
-       struct rte_red red;
+#ifdef RTE_SCHED_AQM
+       RTE_STD_C11
+       union {
+               struct rte_red red;
+               struct rte_pie pie;
+       };
 #endif
 };
 
@@ -183,8 +187,13 @@ struct rte_sched_subport {
        /* Pipe queues size */
        uint16_t qsize[RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE];
 
-#ifdef RTE_SCHED_RED
-       struct rte_red_config 
red_config[RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE][RTE_COLORS];
+       enum rte_sched_aqm_mode aqm;
+#ifdef RTE_SCHED_AQM
+       RTE_STD_C11
+       union {
+               struct rte_red_config 
wred_config[RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE][RTE_COLORS];
+               struct rte_pie_config 
pie_config[RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE];
+       };
 #endif
 
        /* Scheduling loop detection */
@@ -1078,6 +1087,91 @@ rte_sched_free_memory(struct rte_sched_port *port, 
uint32_t n_subports)
        rte_free(port);
 }
 
+#ifdef RTE_SCHED_AQM
+
+static int
+rte_sched_red_config(struct rte_sched_port *port,
+       struct rte_sched_subport *s,
+       struct rte_sched_subport_params *params,
+       uint32_t n_subports)
+{
+       uint32_t i;
+
+       for (i = 0; i < RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE; i++) {
+
+               uint32_t j;
+
+               for (j = 0; j < RTE_COLORS; j++) {
+                       /* if min/max are both zero, then RED is disabled */
+                       if ((params->wred_params[i][j].min_th |
+                                params->wred_params[i][j].max_th) == 0) {
+                               continue;
+                       }
+
+                       if (rte_red_config_init(&s->wred_config[i][j],
+                               params->wred_params[i][j].wq_log2,
+                               params->wred_params[i][j].min_th,
+                               params->wred_params[i][j].max_th,
+                               params->wred_params[i][j].maxp_inv) != 0) {
+                               rte_sched_free_memory(port, n_subports);
+
+                               RTE_LOG(NOTICE, SCHED,
+                               "%s: RED configuration init fails\n", __func__);
+                               return -EINVAL;
+                       }
+               }
+       }
+       s->aqm = RTE_SCHED_AQM_WRED;
+       return 0;
+}
+
+static int
+rte_sched_pie_config(struct rte_sched_port *port,
+       struct rte_sched_subport *s,
+       struct rte_sched_subport_params *params,
+       uint32_t n_subports)
+{
+       uint32_t i;
+
+       for (i = 0; i < RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE; i++) {
+               if (params->pie_params[i].tailq_th > params->qsize[i]) {
+                       RTE_LOG(NOTICE, SCHED,
+                       "%s: PIE tailq threshold incorrect\n", __func__);
+                       return -EINVAL;
+               }
+
+               if (rte_pie_config_init(&s->pie_config[i],
+                       params->pie_params[i].qdelay_ref,
+                       params->pie_params[i].dp_update_interval,
+                       params->pie_params[i].max_burst,
+                       params->pie_params[i].tailq_th) != 0) {
+                       rte_sched_free_memory(port, n_subports);
+
+                       RTE_LOG(NOTICE, SCHED,
+                       "%s: PIE configuration init fails\n", __func__);
+                       return -EINVAL;
+                       }
+       }
+       s->aqm = RTE_SCHED_AQM_PIE;
+       return 0;
+}
+
+static int
+rte_sched_aqm_config(struct rte_sched_port *port,
+       struct rte_sched_subport *s,
+       struct rte_sched_subport_params *params,
+       uint32_t n_subports)
+{
+       if (params->aqm == RTE_SCHED_AQM_WRED)
+               return rte_sched_red_config(port, s, params, n_subports);
+
+       else if (params->aqm == RTE_SCHED_AQM_PIE)
+               return rte_sched_pie_config(port, s, params, n_subports);
+
+       return -EINVAL;
+}
+#endif
+
 int
 rte_sched_subport_config(struct rte_sched_port *port,
        uint32_t subport_id,
@@ -1167,29 +1261,11 @@ rte_sched_subport_config(struct rte_sched_port *port,
                s->n_pipe_profiles = params->n_pipe_profiles;
                s->n_max_pipe_profiles = params->n_max_pipe_profiles;
 
-#ifdef RTE_SCHED_RED
-               for (i = 0; i < RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE; i++) {
-                       uint32_t j;
-
-                       for (j = 0; j < RTE_COLORS; j++) {
-                       /* if min/max are both zero, then RED is disabled */
-                               if ((params->red_params[i][j].min_th |
-                                    params->red_params[i][j].max_th) == 0) {
-                                       continue;
-                               }
-
-                               if (rte_red_config_init(&s->red_config[i][j],
-                                   params->red_params[i][j].wq_log2,
-                                   params->red_params[i][j].min_th,
-                                   params->red_params[i][j].max_th,
-                                   params->red_params[i][j].maxp_inv) != 0) {
-                                       RTE_LOG(NOTICE, SCHED,
-                                       "%s: RED configuration init fails\n",
-                                       __func__);
-                                       ret = -EINVAL;
-                                       goto out;
-                               }
-                       }
+#ifdef RTE_SCHED_AQM
+               status = rte_sched_aqm_config(port, s, params, n_subports);
+               if (status) {
+                       RTE_LOG(NOTICE, SCHED, "%s: AQM configuration fails\n", 
__func__);
+                       return status;
                }
 #endif
 
@@ -1718,29 +1794,20 @@ rte_sched_port_update_subport_stats(struct 
rte_sched_port *port,
        subport->stats.n_bytes_tc[tc_index] += pkt_len;
 }
 
-#ifdef RTE_SCHED_RED
-static inline void
-rte_sched_port_update_subport_stats_on_drop(struct rte_sched_port *port,
-       struct rte_sched_subport *subport,
-       uint32_t qindex,
-       struct rte_mbuf *pkt,
-       uint32_t red)
-#else
 static inline void
 rte_sched_port_update_subport_stats_on_drop(struct rte_sched_port *port,
        struct rte_sched_subport *subport,
        uint32_t qindex,
        struct rte_mbuf *pkt,
-       __rte_unused uint32_t red)
-#endif
+       __rte_unused uint32_t drops)
 {
        uint32_t tc_index = rte_sched_port_pipe_tc(port, qindex);
        uint32_t pkt_len = pkt->pkt_len;
 
        subport->stats.n_pkts_tc_dropped[tc_index] += 1;
        subport->stats.n_bytes_tc_dropped[tc_index] += pkt_len;
-#ifdef RTE_SCHED_RED
-       subport->stats.n_pkts_red_dropped[tc_index] += red;
+#ifdef RTE_SCHED_AQM
+       subport->stats.n_pkts_aqm_dropped[tc_index] += drops;
 #endif
 }
 
@@ -1756,58 +1823,61 @@ rte_sched_port_update_queue_stats(struct 
rte_sched_subport *subport,
        qe->stats.n_bytes += pkt_len;
 }
 
-#ifdef RTE_SCHED_RED
-static inline void
-rte_sched_port_update_queue_stats_on_drop(struct rte_sched_subport *subport,
-       uint32_t qindex,
-       struct rte_mbuf *pkt,
-       uint32_t red)
-#else
 static inline void
 rte_sched_port_update_queue_stats_on_drop(struct rte_sched_subport *subport,
        uint32_t qindex,
        struct rte_mbuf *pkt,
-       __rte_unused uint32_t red)
-#endif
+       __rte_unused uint32_t drops)
 {
        struct rte_sched_queue_extra *qe = subport->queue_extra + qindex;
        uint32_t pkt_len = pkt->pkt_len;
 
        qe->stats.n_pkts_dropped += 1;
        qe->stats.n_bytes_dropped += pkt_len;
-#ifdef RTE_SCHED_RED
-       qe->stats.n_pkts_red_dropped += red;
+#ifdef RTE_SCHED_AQM
+       qe->stats.n_pkts_aqm_dropped += drops;
 #endif
 }
 
 #endif /* RTE_SCHED_COLLECT_STATS */
 
-#ifdef RTE_SCHED_RED
+#ifdef RTE_SCHED_AQM
 
 static inline int
-rte_sched_port_red_drop(struct rte_sched_port *port,
+rte_sched_port_aqm_drop(struct rte_sched_port *port,
        struct rte_sched_subport *subport,
        struct rte_mbuf *pkt,
        uint32_t qindex,
        uint16_t qlen)
 {
        struct rte_sched_queue_extra *qe;
-       struct rte_red_config *red_cfg;
-       struct rte_red *red;
        uint32_t tc_index;
-       enum rte_color color;
 
        tc_index = rte_sched_port_pipe_tc(port, qindex);
-       color = rte_sched_port_pkt_read_color(pkt);
-       red_cfg = &subport->red_config[tc_index][color];
+       qe = subport->queue_extra + qindex;
 
-       if ((red_cfg->min_th | red_cfg->max_th) == 0)
-               return 0;
+       /* WRED */
+       if (subport->aqm == RTE_SCHED_AQM_WRED) {
+               struct rte_red_config *red_cfg;
+               struct rte_red *red;
+               enum rte_color color;
 
-       qe = subport->queue_extra + qindex;
-       red = &qe->red;
+               color = rte_sched_port_pkt_read_color(pkt);
+               red_cfg = &subport->wred_config[tc_index][color];
+
+               if ((red_cfg->min_th | red_cfg->max_th) == 0)
+                       return 0;
 
-       return rte_red_enqueue(red_cfg, red, qlen, port->time);
+               red = &qe->red;
+
+               return rte_red_enqueue(red_cfg, red, qlen, port->time);
+       }
+
+       /* PIE */
+       struct rte_pie_config *pie_cfg = &subport->pie_config[tc_index];
+       struct rte_pie *pie = &qe->pie;
+
+       return rte_pie_enqueue(pie_cfg, pie, pkt->pkt_len, qlen, 
port->time_cpu_cycles);
 }
 
 static inline void
@@ -1815,14 +1885,29 @@ rte_sched_port_set_queue_empty_timestamp(struct 
rte_sched_port *port,
        struct rte_sched_subport *subport, uint32_t qindex)
 {
        struct rte_sched_queue_extra *qe = subport->queue_extra + qindex;
-       struct rte_red *red = &qe->red;
+       if (subport->aqm == RTE_SCHED_AQM_WRED) {
+               struct rte_red *red = &qe->red;
+
+               rte_red_mark_queue_empty(red, port->time);
+       }
+}
+
+static inline void
+rte_sched_port_pie_dequeue(struct rte_sched_subport *subport,
+uint32_t qindex, uint32_t pkt_len, uint64_t time) {
+       struct rte_sched_queue_extra *qe = subport->queue_extra + qindex;
+       struct rte_pie *pie = &qe->pie;
 
-       rte_red_mark_queue_empty(red, port->time);
+       /* Update queue length */
+       pie->qlen -= 1;
+       pie->qlen_bytes -= pkt_len;
+
+       rte_pie_dequeue(pie, pkt_len, time);
 }
 
 #else
 
-static inline int rte_sched_port_red_drop(struct rte_sched_port *port 
__rte_unused,
+static inline int rte_sched_port_aqm_drop(struct rte_sched_port *port 
__rte_unused,
        struct rte_sched_subport *subport __rte_unused,
        struct rte_mbuf *pkt __rte_unused,
        uint32_t qindex __rte_unused,
@@ -1833,7 +1918,7 @@ static inline int rte_sched_port_red_drop(struct 
rte_sched_port *port __rte_unus
 
 #define rte_sched_port_set_queue_empty_timestamp(port, subport, qindex)
 
-#endif /* RTE_SCHED_RED */
+#endif /* RTE_SCHED_AQM */
 
 #ifdef RTE_SCHED_DEBUG
 
@@ -1929,7 +2014,7 @@ rte_sched_port_enqueue_qwa(struct rte_sched_port *port,
        qlen = q->qw - q->qr;
 
        /* Drop the packet (and update drop stats) when queue is full */
-       if (unlikely(rte_sched_port_red_drop(port, subport, pkt, qindex, qlen) 
||
+       if (unlikely(rte_sched_port_aqm_drop(port, subport, pkt, qindex, qlen) 
||
                     (qlen >= qsize))) {
                rte_pktmbuf_free(pkt);
 #ifdef RTE_SCHED_COLLECT_STATS
@@ -2402,6 +2487,7 @@ grinder_schedule(struct rte_sched_port *port,
 {
        struct rte_sched_grinder *grinder = subport->grinder + pos;
        struct rte_sched_queue *queue = grinder->queue[grinder->qpos];
+       uint32_t qindex = grinder->qindex[grinder->qpos];
        struct rte_mbuf *pkt = grinder->pkt;
        uint32_t pkt_len = pkt->pkt_len + port->frame_overhead;
        uint32_t be_tc_active;
@@ -2421,15 +2507,19 @@ grinder_schedule(struct rte_sched_port *port,
                (pkt_len * grinder->wrr_cost[grinder->qpos]) & be_tc_active;
 
        if (queue->qr == queue->qw) {
-               uint32_t qindex = grinder->qindex[grinder->qpos];
-
                rte_bitmap_clear(subport->bmp, qindex);
                grinder->qmask &= ~(1 << grinder->qpos);
                if (be_tc_active)
                        grinder->wrr_mask[grinder->qpos] = 0;
+
                rte_sched_port_set_queue_empty_timestamp(port, subport, qindex);
        }
 
+#ifdef RTE_SCHED_AQM
+       if (subport->aqm == RTE_SCHED_AQM_PIE)
+               rte_sched_port_pie_dequeue(subport, qindex, pkt_len, 
port->time_cpu_cycles);
+#endif
+
        /* Reset pipe loop detection */
        subport->pipe_loop = RTE_SCHED_PIPE_INVALID;
        grinder->productive = 1;
diff --git a/lib/sched/rte_sched.h b/lib/sched/rte_sched.h
index c1a772b70c..a5fe6266cd 100644
--- a/lib/sched/rte_sched.h
+++ b/lib/sched/rte_sched.h
@@ -61,9 +61,10 @@ extern "C" {
 #include <rte_mbuf.h>
 #include <rte_meter.h>
 
-/** Random Early Detection (RED) */
-#ifdef RTE_SCHED_RED
+/** Active Queue Management */
+#ifdef RTE_SCHED_AQM
 #include "rte_red.h"
+#include "rte_pie.h"
 #endif
 
 /** Maximum number of queues per pipe.
@@ -110,6 +111,28 @@ extern "C" {
 #define RTE_SCHED_FRAME_OVERHEAD_DEFAULT      24
 #endif
 
+/**
+ * Active Queue Management (AQM) mode
+ *
+ * This is used for controlling the admission of packets into a packet queue or
+ * group of packet queues on congestion.
+ *
+ * The *Random Early Detection (RED)* algorithm works by proactively dropping
+ * more and more input packets as the queue occupancy builds up. When the queue
+ * is full or almost full, RED effectively works as *tail drop*. The *Weighted
+ * RED* algorithm uses a separate set of RED thresholds for each packet color.
+ *
+ * Similar to RED, Proportional Integral Controller Enhanced (PIE) randomly
+ * drops a packet at the onset of the congestion and tries to control the
+ * latency around the target value. The congestion detection, however, is based
+ * on the queueing latency instead of the queue length like RED. For more
+ * information, refer RFC8033.
+ */
+enum rte_sched_aqm_mode {
+       RTE_SCHED_AQM_WRED, /**< Weighted Random Early Detection (WRED) */
+       RTE_SCHED_AQM_PIE,  /**< Proportional Integral Controller Enhanced 
(PIE) */
+};
+
 /*
  * Pipe configuration parameters. The period and credits_per_period
  * parameters are measured in bytes, with one byte meaning the time
@@ -174,9 +197,17 @@ struct rte_sched_subport_params {
        /** Max allowed profiles in the pipe profile table */
        uint32_t n_max_pipe_profiles;
 
-#ifdef RTE_SCHED_RED
-       /** RED parameters */
-       struct rte_red_params 
red_params[RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE][RTE_COLORS];
+#ifdef RTE_SCHED_AQM
+       /** Active Queue Management mode */
+       enum rte_sched_aqm_mode aqm;
+
+       RTE_STD_C11
+       union {
+               /** WRED parameters */
+               struct rte_red_params 
wred_params[RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE][RTE_COLORS];
+               /** PIE parameters */
+               struct rte_pie_params 
pie_params[RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE];
+       };
 #endif
 };
 
@@ -208,9 +239,9 @@ struct rte_sched_subport_stats {
        /** Number of bytes dropped for each traffic class */
        uint64_t n_bytes_tc_dropped[RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE];
 
-#ifdef RTE_SCHED_RED
-       /** Number of packets dropped by red */
-       uint64_t n_pkts_red_dropped[RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE];
+#ifdef RTE_SCHED_AQM
+       /** Number of packets dropped by active queue management scheme */
+       uint64_t n_pkts_aqm_dropped[RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE];
 #endif
 };
 
@@ -222,9 +253,9 @@ struct rte_sched_queue_stats {
        /** Packets dropped */
        uint64_t n_pkts_dropped;
 
-#ifdef RTE_SCHED_RED
-       /** Packets dropped by RED */
-       uint64_t n_pkts_red_dropped;
+#ifdef RTE_SCHED_AQM
+       /** Packets dropped by active queue management scheme */
+       uint64_t n_pkts_aqm_dropped;
 #endif
 
        /** Bytes successfully written */
diff --git a/lib/sched/version.map b/lib/sched/version.map
index ace284b7de..3422821ac8 100644
--- a/lib/sched/version.map
+++ b/lib/sched/version.map
@@ -30,4 +30,7 @@ EXPERIMENTAL {
        rte_sched_subport_pipe_profile_add;
        # added in 20.11
        rte_sched_port_subport_profile_add;
+
+       rte_pie_rt_data_init;
+       rte_pie_config_init;
 };
-- 
2.25.1

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