[PATCH v2] Revert "sched: enable traffic class oversubscription unconditionally"

[Megha Ajmera <megha.ajmera@intel.com>]

This reverts commit d91c4b1bb5a938734fe8e66da8f965304919f38e.

When enabling TC OV unconditionally, it is observed the performance
drops by ~20% hence reverting this commit.

Fixes: d91c4b1bb5a9 ("sched: enable traffic class oversubscription
unconditionally")

Signed-off-by: Megha Ajmera <megha.ajmera@intel.com>
---
 config/rte_config.h                      |  1 +
 drivers/net/softnic/rte_eth_softnic_tm.c | 18 +++++
 examples/qos_sched/init.c                |  2 +
 lib/sched/rte_sched.c                    | 90 ++++++++++++++++++++++++
 4 files changed, 111 insertions(+)

diff --git a/config/rte_config.h b/config/rte_config.h
index 8eb29c1525..de6fea5b67 100644
--- a/config/rte_config.h
+++ b/config/rte_config.h
@@ -90,6 +90,7 @@
 
 /* rte_sched defines */
 #undef RTE_SCHED_CMAN
+#undef RTE_SCHED_SUBPORT_TC_OV
 
 /* rte_graph defines */
 #define RTE_GRAPH_BURST_SIZE 256
diff --git a/drivers/net/softnic/rte_eth_softnic_tm.c b/drivers/net/softnic/rte_eth_softnic_tm.c
index 6a7766ba1c..e74092ce7f 100644
--- a/drivers/net/softnic/rte_eth_softnic_tm.c
+++ b/drivers/net/softnic/rte_eth_softnic_tm.c
@@ -595,9 +595,15 @@ static const struct rte_tm_level_capabilities tm_level_cap[] = {
 			.sched_sp_n_priorities_max = 1,
 			.sched_wfq_n_children_per_group_max = UINT32_MAX,
 			.sched_wfq_n_groups_max = 1,
+#ifdef RTE_SCHED_SUBPORT_TC_OV
 			.sched_wfq_weight_max = UINT32_MAX,
 			.sched_wfq_packet_mode_supported = 0,
 			.sched_wfq_byte_mode_supported = 1,
+#else
+			.sched_wfq_weight_max = 1,
+			.sched_wfq_packet_mode_supported = 0,
+			.sched_wfq_byte_mode_supported = 1,
+#endif
 
 			.stats_mask = STATS_MASK_DEFAULT,
 		} },
@@ -2822,6 +2828,8 @@ pmd_tm_hierarchy_commit(struct rte_eth_dev *dev,
 	return 0;
 }
 
+#ifdef RTE_SCHED_SUBPORT_TC_OV
+
 static int
 update_pipe_weight(struct rte_eth_dev *dev, struct tm_node *np, uint32_t weight)
 {
@@ -2859,6 +2867,8 @@ update_pipe_weight(struct rte_eth_dev *dev, struct tm_node *np, uint32_t weight)
 	return 0;
 }
 
+#endif
+
 static int
 update_queue_weight(struct rte_eth_dev *dev,
 	struct tm_node *nq, uint32_t weight)
@@ -2973,6 +2983,7 @@ pmd_tm_node_parent_update(struct rte_eth_dev *dev,
 			rte_strerror(EINVAL));
 		/* fall-through */
 	case TM_NODE_LEVEL_PIPE:
+#ifdef RTE_SCHED_SUBPORT_TC_OV
 		if (update_pipe_weight(dev, n, weight))
 			return -rte_tm_error_set(error,
 				EINVAL,
@@ -2980,6 +2991,13 @@ pmd_tm_node_parent_update(struct rte_eth_dev *dev,
 				NULL,
 				rte_strerror(EINVAL));
 		return 0;
+#else
+		return -rte_tm_error_set(error,
+			EINVAL,
+			RTE_TM_ERROR_TYPE_NODE_WEIGHT,
+			NULL,
+			rte_strerror(EINVAL));
+#endif
 		/* fall-through */
 	case TM_NODE_LEVEL_TC:
 		return -rte_tm_error_set(error,
diff --git a/examples/qos_sched/init.c b/examples/qos_sched/init.c
index 8a0fb8a374..3c1f0bc680 100644
--- a/examples/qos_sched/init.c
+++ b/examples/qos_sched/init.c
@@ -183,7 +183,9 @@ static struct rte_sched_pipe_params pipe_profiles[MAX_SCHED_PIPE_PROFILES] = {
 		.tc_rate = {305175, 305175, 305175, 305175, 305175, 305175,
 			305175, 305175, 305175, 305175, 305175, 305175, 305175},
 		.tc_period = 40,
+#ifdef RTE_SCHED_SUBPORT_TC_OV
 		.tc_ov_weight = 1,
+#endif
 
 		.wrr_weights = {1, 1, 1, 1},
 	},
diff --git a/lib/sched/rte_sched.c b/lib/sched/rte_sched.c
index ec74bee939..7298df9e90 100644
--- a/lib/sched/rte_sched.c
+++ b/lib/sched/rte_sched.c
@@ -1317,12 +1317,14 @@ rte_sched_subport_config(struct rte_sched_port *port,
 		for (i = 0; i < RTE_SCHED_PORT_N_GRINDERS; i++)
 			s->grinder_base_bmp_pos[i] = RTE_SCHED_PIPE_INVALID;
 
+#ifdef RTE_SCHED_SUBPORT_TC_OV
 		/* TC oversubscription */
 		s->tc_ov_wm_min = port->mtu;
 		s->tc_ov_period_id = 0;
 		s->tc_ov = 0;
 		s->tc_ov_n = 0;
 		s->tc_ov_rate = 0;
+#endif
 	}
 
 	{
@@ -1342,9 +1344,11 @@ rte_sched_subport_config(struct rte_sched_port *port,
 			else
 				profile->tc_credits_per_period[i] = 0;
 
+#ifdef RTE_SCHED_SUBPORT_TC_OV
 		s->tc_ov_wm_max = rte_sched_time_ms_to_bytes(profile->tc_period,
 							s->pipe_tc_be_rate_max);
 		s->tc_ov_wm = s->tc_ov_wm_max;
+#endif
 		s->profile = subport_profile_id;
 
 	}
@@ -2251,6 +2255,50 @@ rte_sched_port_enqueue(struct rte_sched_port *port, struct rte_mbuf **pkts,
 	return result;
 }
 
+#ifndef RTE_SCHED_SUBPORT_TC_OV
+
+static inline void
+grinder_credits_update(struct rte_sched_port *port,
+	struct rte_sched_subport *subport, uint32_t pos)
+{
+	struct rte_sched_grinder *grinder = subport->grinder + pos;
+	struct rte_sched_pipe *pipe = grinder->pipe;
+	struct rte_sched_pipe_profile *params = grinder->pipe_params;
+	struct rte_sched_subport_profile *sp = grinder->subport_params;
+	uint64_t n_periods;
+	uint32_t i;
+
+	/* Subport TB */
+	n_periods = (port->time - subport->tb_time) / sp->tb_period;
+	subport->tb_credits += n_periods * sp->tb_credits_per_period;
+	subport->tb_credits = RTE_MIN(subport->tb_credits, sp->tb_size);
+	subport->tb_time += n_periods * sp->tb_period;
+
+	/* Pipe TB */
+	n_periods = (port->time - pipe->tb_time) / params->tb_period;
+	pipe->tb_credits += n_periods * params->tb_credits_per_period;
+	pipe->tb_credits = RTE_MIN(pipe->tb_credits, params->tb_size);
+	pipe->tb_time += n_periods * params->tb_period;
+
+	/* Subport TCs */
+	if (unlikely(port->time >= subport->tc_time)) {
+		for (i = 0; i < RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE; i++)
+			subport->tc_credits[i] = sp->tc_credits_per_period[i];
+
+		subport->tc_time = port->time + sp->tc_period;
+	}
+
+	/* Pipe TCs */
+	if (unlikely(port->time >= pipe->tc_time)) {
+		for (i = 0; i < RTE_SCHED_TRAFFIC_CLASSES_PER_PIPE; i++)
+			pipe->tc_credits[i] = params->tc_credits_per_period[i];
+
+		pipe->tc_time = port->time + params->tc_period;
+	}
+}
+
+#else
+
 static inline uint64_t
 grinder_tc_ov_credits_update(struct rte_sched_port *port,
 	struct rte_sched_subport *subport, uint32_t pos)
@@ -2345,6 +2393,46 @@ grinder_credits_update(struct rte_sched_port *port,
 	}
 }
 
+#endif /* RTE_SCHED_TS_CREDITS_UPDATE, RTE_SCHED_SUBPORT_TC_OV */
+
+
+#ifndef RTE_SCHED_SUBPORT_TC_OV
+
+static inline int
+grinder_credits_check(struct rte_sched_port *port,
+	struct rte_sched_subport *subport, uint32_t pos)
+{
+	struct rte_sched_grinder *grinder = subport->grinder + pos;
+	struct rte_sched_pipe *pipe = grinder->pipe;
+	struct rte_mbuf *pkt = grinder->pkt;
+	uint32_t tc_index = grinder->tc_index;
+	uint64_t pkt_len = pkt->pkt_len + port->frame_overhead;
+	uint64_t subport_tb_credits = subport->tb_credits;
+	uint64_t subport_tc_credits = subport->tc_credits[tc_index];
+	uint64_t pipe_tb_credits = pipe->tb_credits;
+	uint64_t pipe_tc_credits = pipe->tc_credits[tc_index];
+	int enough_credits;
+
+	/* Check queue credits */
+	enough_credits = (pkt_len <= subport_tb_credits) &&
+		(pkt_len <= subport_tc_credits) &&
+		(pkt_len <= pipe_tb_credits) &&
+		(pkt_len <= pipe_tc_credits);
+
+	if (!enough_credits)
+		return 0;
+
+	/* Update port credits */
+	subport->tb_credits -= pkt_len;
+	subport->tc_credits[tc_index] -= pkt_len;
+	pipe->tb_credits -= pkt_len;
+	pipe->tc_credits[tc_index] -= pkt_len;
+
+	return 1;
+}
+
+#else
+
 static inline int
 grinder_credits_check(struct rte_sched_port *port,
 	struct rte_sched_subport *subport, uint32_t pos)
@@ -2391,6 +2479,8 @@ grinder_credits_check(struct rte_sched_port *port,
 	return 1;
 }
 
+#endif /* RTE_SCHED_SUBPORT_TC_OV */
+
 
 static inline int
 grinder_schedule(struct rte_sched_port *port,
-- 
2.25.1