[dpdk-dev] [PATCH v9 20/23] event/dlb: add PMD's token pop public interface

[Timothy McDaniel <timothy.mcdaniel@intel.com>]

The PMD uses a public interface to allow applications to
control the token pop mode. Supported token pop modes are
as follows, and they impact core scheduling affinity for
ldb ports.

AUTO_POP: Pop the CQ tokens immediately after dequeueing.
DELAYED_POP: Pop CQ tokens after (dequeue_depth - 1) events
	     are released. Supported on load-balanced ports
	     only.
DEFERRED_POP: Pop the CQ tokens during next dequeue operation.

Signed-off-by: Timothy McDaniel <timothy.mcdaniel@intel.com>
Reviewed-by: Gage Eads <gage.eads@intel.com>
---
 doc/api/doxy-api-index.md       |   1 +
 drivers/event/dlb/dlb.c         | 121 ++++++++++++++++++++++++++++++++++++----
 drivers/event/dlb/dlb_priv.h    |   3 +
 drivers/event/dlb/meson.build   |   4 +-
 drivers/event/dlb/rte_pmd_dlb.c |  38 +++++++++++++
 drivers/event/dlb/rte_pmd_dlb.h |  77 +++++++++++++++++++++++++
 drivers/event/dlb/version.map   |   6 ++
 7 files changed, 237 insertions(+), 13 deletions(-)
 create mode 100644 drivers/event/dlb/rte_pmd_dlb.c
 create mode 100644 drivers/event/dlb/rte_pmd_dlb.h

diff --git a/doc/api/doxy-api-index.md b/doc/api/doxy-api-index.md
index a9c12d1..1c83bf4 100644
--- a/doc/api/doxy-api-index.md
+++ b/doc/api/doxy-api-index.md
@@ -52,6 +52,7 @@ The public API headers are grouped by topics:
   [dpaa2_cmdif]        (@ref rte_pmd_dpaa2_cmdif.h),
   [dpaa2_qdma]         (@ref rte_pmd_dpaa2_qdma.h),
   [crypto_scheduler]   (@ref rte_cryptodev_scheduler.h)
+  [dlb]		       (@ref rte_pmd_dlb.h),
 
 - **memory**:
   [memseg]             (@ref rte_memory.h),
diff --git a/drivers/event/dlb/dlb.c b/drivers/event/dlb/dlb.c
index cdabc9b..4e1af0a 100644
--- a/drivers/event/dlb/dlb.c
+++ b/drivers/event/dlb/dlb.c
@@ -1021,6 +1021,33 @@ dlb_hw_create_ldb_port(struct dlb_eventdev *dlb,
 
 	qm_port->dequeue_depth = dequeue_depth;
 
+	/* When using the reserved token scheme, token_pop_thresh is
+	 * initially 2 * dequeue_depth. Once the tokens are reserved,
+	 * the enqueue code re-assigns it to dequeue_depth.
+	 */
+	qm_port->token_pop_thresh = cq_depth;
+
+	/* When the deferred scheduling vdev arg is selected, use deferred pop
+	 * for all single-entry CQs.
+	 */
+	if (cfg.cq_depth == 1 || (cfg.cq_depth == 2 && use_rsvd_token_scheme)) {
+		if (dlb->defer_sched)
+			qm_port->token_pop_mode = DEFERRED_POP;
+	}
+
+	/* The default enqueue functions do not include delayed-pop support for
+	 * performance reasons.
+	 */
+	if (qm_port->token_pop_mode == DELAYED_POP) {
+		dlb->event_dev->enqueue = dlb_event_enqueue_delayed;
+		dlb->event_dev->enqueue_burst =
+			dlb_event_enqueue_burst_delayed;
+		dlb->event_dev->enqueue_new_burst =
+			dlb_event_enqueue_new_burst_delayed;
+		dlb->event_dev->enqueue_forward_burst =
+			dlb_event_enqueue_forward_burst_delayed;
+	}
+
 	qm_port->owed_tokens = 0;
 	qm_port->issued_releases = 0;
 
@@ -1181,6 +1208,8 @@ dlb_hw_create_dir_port(struct dlb_eventdev *dlb,
 
 	qm_port->dequeue_depth = dequeue_depth;
 
+	/* Directed ports are auto-pop, by default. */
+	qm_port->token_pop_mode = AUTO_POP;
 	qm_port->owed_tokens = 0;
 	qm_port->issued_releases = 0;
 
@@ -2681,7 +2710,8 @@ dlb_consume_qe_immediate(struct dlb_port *qm_port, int num)
 static inline uint16_t
 __dlb_event_enqueue_burst(void *event_port,
 			  const struct rte_event events[],
-			  uint16_t num)
+			  uint16_t num,
+			  bool use_delayed)
 {
 	struct dlb_eventdev_port *ev_port = event_port;
 	struct dlb_port *qm_port = &ev_port->qm_port;
@@ -2709,6 +2739,35 @@ __dlb_event_enqueue_burst(void *event_port,
 
 		for (; j < DLB_NUM_QES_PER_CACHE_LINE && (i + j) < num; j++) {
 			const struct rte_event *ev = &events[i + j];
+			int16_t thresh = qm_port->token_pop_thresh;
+
+			if (use_delayed &&
+			    qm_port->token_pop_mode == DELAYED_POP &&
+			    (ev->op == RTE_EVENT_OP_FORWARD ||
+			     ev->op == RTE_EVENT_OP_RELEASE) &&
+			    qm_port->issued_releases >= thresh - 1) {
+				/* Insert the token pop QE and break out. This
+				 * may result in a partial HCW, but that is
+				 * simpler than supporting arbitrary QE
+				 * insertion.
+				 */
+				dlb_construct_token_pop_qe(qm_port, j);
+
+				/* Reset the releases for the next QE batch */
+				qm_port->issued_releases -= thresh;
+
+				/* When using delayed token pop mode, the
+				 * initial token threshold is the full CQ
+				 * depth. After the first token pop, we need to
+				 * reset it to the dequeue_depth.
+				 */
+				qm_port->token_pop_thresh =
+					qm_port->dequeue_depth;
+
+				pop_offs = 1;
+				j++;
+				break;
+			}
 
 			if (dlb_event_enqueue_prep(ev_port, qm_port, ev,
 						   port_data, &sched_types[j],
@@ -2744,7 +2803,7 @@ dlb_event_enqueue_burst(void *event_port,
 			const struct rte_event events[],
 			uint16_t num)
 {
-	return __dlb_event_enqueue_burst(event_port, events, num);
+	return __dlb_event_enqueue_burst(event_port, events, num, false);
 }
 
 static inline uint16_t
@@ -2752,21 +2811,21 @@ dlb_event_enqueue_burst_delayed(void *event_port,
 				const struct rte_event events[],
 				uint16_t num)
 {
-	return __dlb_event_enqueue_burst(event_port, events, num);
+	return __dlb_event_enqueue_burst(event_port, events, num, true);
 }
 
 static inline uint16_t
 dlb_event_enqueue(void *event_port,
 		  const struct rte_event events[])
 {
-	return __dlb_event_enqueue_burst(event_port, events, 1);
+	return __dlb_event_enqueue_burst(event_port, events, 1, false);
 }
 
 static inline uint16_t
 dlb_event_enqueue_delayed(void *event_port,
 			  const struct rte_event events[])
 {
-	return __dlb_event_enqueue_burst(event_port, events, 1);
+	return __dlb_event_enqueue_burst(event_port, events, 1, true);
 }
 
 static uint16_t
@@ -2774,7 +2833,7 @@ dlb_event_enqueue_new_burst(void *event_port,
 			    const struct rte_event events[],
 			    uint16_t num)
 {
-	return __dlb_event_enqueue_burst(event_port, events, num);
+	return __dlb_event_enqueue_burst(event_port, events, num, false);
 }
 
 static uint16_t
@@ -2782,7 +2841,7 @@ dlb_event_enqueue_new_burst_delayed(void *event_port,
 				    const struct rte_event events[],
 				    uint16_t num)
 {
-	return __dlb_event_enqueue_burst(event_port, events, num);
+	return __dlb_event_enqueue_burst(event_port, events, num, true);
 }
 
 static uint16_t
@@ -2790,7 +2849,7 @@ dlb_event_enqueue_forward_burst(void *event_port,
 				const struct rte_event events[],
 				uint16_t num)
 {
-	return __dlb_event_enqueue_burst(event_port, events, num);
+	return __dlb_event_enqueue_burst(event_port, events, num, false);
 }
 
 static uint16_t
@@ -2798,7 +2857,7 @@ dlb_event_enqueue_forward_burst_delayed(void *event_port,
 					const struct rte_event events[],
 					uint16_t num)
 {
-	return __dlb_event_enqueue_burst(event_port, events, num);
+	return __dlb_event_enqueue_burst(event_port, events, num, true);
 }
 
 static __rte_always_inline int
@@ -3203,7 +3262,8 @@ dlb_hw_dequeue(struct dlb_eventdev *dlb,
 
 	qm_port->owed_tokens += num;
 
-	dlb_consume_qe_immediate(qm_port, num);
+	if (num && qm_port->token_pop_mode == AUTO_POP)
+		dlb_consume_qe_immediate(qm_port, num);
 
 	ev_port->outstanding_releases += num;
 
@@ -3373,7 +3433,8 @@ dlb_hw_dequeue_sparse(struct dlb_eventdev *dlb,
 
 	qm_port->owed_tokens += num;
 
-	dlb_consume_qe_immediate(qm_port, num);
+	if (num && qm_port->token_pop_mode == AUTO_POP)
+		dlb_consume_qe_immediate(qm_port, num);
 
 	ev_port->outstanding_releases += num;
 
@@ -3417,6 +3478,28 @@ dlb_event_release(struct dlb_eventdev *dlb, uint8_t port_id, int n)
 		qm_port->qe4[3].cmd_byte = 0;
 
 		for (; j < DLB_NUM_QES_PER_CACHE_LINE && (i + j) < n; j++) {
+			int16_t thresh = qm_port->token_pop_thresh;
+
+			if (qm_port->token_pop_mode == DELAYED_POP &&
+			    qm_port->issued_releases >= thresh - 1) {
+				/* Insert the token pop QE */
+				dlb_construct_token_pop_qe(qm_port, j);
+
+				/* Reset the releases for the next QE batch */
+				qm_port->issued_releases -= thresh;
+
+				/* When using delayed token pop mode, the
+				 * initial token threshold is the full CQ
+				 * depth. After the first token pop, we need to
+				 * reset it to the dequeue_depth.
+				 */
+				qm_port->token_pop_thresh =
+					qm_port->dequeue_depth;
+
+				pop_offs = 1;
+				j++;
+				break;
+			}
 
 			qm_port->qe4[j].cmd_byte = DLB_COMP_CMD_BYTE;
 			qm_port->issued_releases++;
@@ -3449,6 +3532,7 @@ dlb_event_dequeue_burst(void *event_port, struct rte_event *ev, uint16_t num,
 			uint64_t wait)
 {
 	struct dlb_eventdev_port *ev_port = event_port;
+	struct dlb_port *qm_port = &ev_port->qm_port;
 	struct dlb_eventdev *dlb = ev_port->dlb;
 	uint16_t cnt;
 	int ret;
@@ -3468,6 +3552,10 @@ dlb_event_dequeue_burst(void *event_port, struct rte_event *ev, uint16_t num,
 		DLB_INC_STAT(ev_port->stats.tx_implicit_rel, out_rels);
 	}
 
+	if (qm_port->token_pop_mode == DEFERRED_POP &&
+			qm_port->owed_tokens)
+		dlb_consume_qe_immediate(qm_port, qm_port->owed_tokens);
+
 	cnt = dlb_hw_dequeue(dlb, ev_port, ev, num, wait);
 
 	DLB_INC_STAT(ev_port->stats.traffic.total_polls, 1);
@@ -3486,6 +3574,7 @@ dlb_event_dequeue_burst_sparse(void *event_port, struct rte_event *ev,
 			       uint16_t num, uint64_t wait)
 {
 	struct dlb_eventdev_port *ev_port = event_port;
+	struct dlb_port *qm_port = &ev_port->qm_port;
 	struct dlb_eventdev *dlb = ev_port->dlb;
 	uint16_t cnt;
 	int ret;
@@ -3505,6 +3594,10 @@ dlb_event_dequeue_burst_sparse(void *event_port, struct rte_event *ev,
 		DLB_INC_STAT(ev_port->stats.tx_implicit_rel, out_rels);
 	}
 
+	if (qm_port->token_pop_mode == DEFERRED_POP &&
+	    qm_port->owed_tokens)
+		dlb_consume_qe_immediate(qm_port, qm_port->owed_tokens);
+
 	cnt = dlb_hw_dequeue_sparse(dlb, ev_port, ev, num, wait);
 
 	DLB_INC_STAT(ev_port->stats.traffic.total_polls, 1);
@@ -3811,7 +3904,7 @@ dlb_primary_eventdev_probe(struct rte_eventdev *dev,
 			   struct dlb_devargs *dlb_args)
 {
 	struct dlb_eventdev *dlb;
-	int err;
+	int err, i;
 
 	dlb = dev->data->dev_private;
 
@@ -3860,6 +3953,10 @@ dlb_primary_eventdev_probe(struct rte_eventdev *dev,
 		return err;
 	}
 
+	/* Initialize each port's token pop mode */
+	for (i = 0; i < DLB_MAX_NUM_PORTS; i++)
+		dlb->ev_ports[i].qm_port.token_pop_mode = AUTO_POP;
+
 	rte_spinlock_init(&dlb->qm_instance.resource_lock);
 
 	dlb_iface_low_level_io_init(dlb);
diff --git a/drivers/event/dlb/dlb_priv.h b/drivers/event/dlb/dlb_priv.h
index adb1f7a..58ff428 100644
--- a/drivers/event/dlb/dlb_priv.h
+++ b/drivers/event/dlb/dlb_priv.h
@@ -16,6 +16,7 @@
 
 #include "dlb_user.h"
 #include "dlb_log.h"
+#include "rte_pmd_dlb.h"
 
 #ifndef RTE_LIBRTE_PMD_DLB_QUELL_STATS
 #define DLB_INC_STAT(_stat, _incr_val) ((_stat) += _incr_val)
@@ -262,6 +263,7 @@ struct dlb_port {
 	bool gen_bit;
 	uint16_t dir_credits;
 	uint32_t dequeue_depth;
+	enum dlb_token_pop_mode token_pop_mode;
 	int pp_mmio_base;
 	uint16_t cached_ldb_credits;
 	uint16_t ldb_pushcount_at_credit_expiry;
@@ -273,6 +275,7 @@ struct dlb_port {
 	uint8_t cq_rsvd_token_deficit;
 	uint16_t owed_tokens;
 	int16_t issued_releases;
+	int16_t token_pop_thresh;
 	int cq_depth;
 	uint16_t cq_idx;
 	uint16_t cq_idx_unmasked;
diff --git a/drivers/event/dlb/meson.build b/drivers/event/dlb/meson.build
index 552ff9d..7f38c30 100644
--- a/drivers/event/dlb/meson.build
+++ b/drivers/event/dlb/meson.build
@@ -12,7 +12,9 @@ sources = files('dlb.c',
 		'dlb_xstats.c',
 		'pf/dlb_main.c',
 		'pf/dlb_pf.c',
-		'pf/base/dlb_resource.c'
+		'pf/base/dlb_resource.c',
+		'rte_pmd_dlb.c',
 )
 
 deps += ['mbuf', 'mempool', 'ring', 'pci', 'bus_pci']
+install_headers('rte_pmd_dlb.h')
diff --git a/drivers/event/dlb/rte_pmd_dlb.c b/drivers/event/dlb/rte_pmd_dlb.c
new file mode 100644
index 0000000..bc802d3
--- /dev/null
+++ b/drivers/event/dlb/rte_pmd_dlb.c
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2020 Intel Corporation
+ */
+
+#include "rte_eventdev.h"
+#include "rte_eventdev_pmd.h"
+#include "rte_pmd_dlb.h"
+#include "dlb_priv.h"
+#include "dlb_inline_fns.h"
+
+int
+rte_pmd_dlb_set_token_pop_mode(uint8_t dev_id,
+			       uint8_t port_id,
+			       enum dlb_token_pop_mode mode)
+{
+	struct dlb_eventdev *dlb;
+	struct rte_eventdev *dev;
+
+	RTE_EVENTDEV_VALID_DEVID_OR_ERR_RET(dev_id, -EINVAL);
+	dev = &rte_eventdevs[dev_id];
+
+	dlb = dlb_pmd_priv(dev);
+
+	if (mode >= NUM_TOKEN_POP_MODES)
+		return -EINVAL;
+
+	/* The event device must be configured, but not yet started */
+	if (!dlb->configured || dlb->run_state != DLB_RUN_STATE_STOPPED)
+		return -EINVAL;
+
+	/* The token pop mode must be set before configuring the port */
+	if (port_id >= dlb->num_ports || dlb->ev_ports[port_id].setup_done)
+		return -EINVAL;
+
+	dlb->ev_ports[port_id].qm_port.token_pop_mode = mode;
+
+	return 0;
+}
diff --git a/drivers/event/dlb/rte_pmd_dlb.h b/drivers/event/dlb/rte_pmd_dlb.h
new file mode 100644
index 0000000..9cf6dd3
--- /dev/null
+++ b/drivers/event/dlb/rte_pmd_dlb.h
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2019-2020 Intel Corporation
+ */
+
+/*!
+ *  @file      rte_pmd_dlb.h
+ *
+ *  @brief     DLB PMD-specific functions
+ *
+ */
+
+#ifndef _RTE_PMD_DLB_H_
+#define _RTE_PMD_DLB_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * Selects the token pop mode for an DLB port.
+ */
+enum dlb_token_pop_mode {
+	/* Pop the CQ tokens immediately after dequeueing. */
+	AUTO_POP,
+	/* Pop CQ tokens after (dequeue_depth - 1) events are released.
+	 * Supported on load-balanced ports only.
+	 */
+	DELAYED_POP,
+	/* Pop the CQ tokens during next dequeue operation. */
+	DEFERRED_POP,
+
+	/* NUM_TOKEN_POP_MODES must be last */
+	NUM_TOKEN_POP_MODES
+};
+
+/*!
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * Configure the token pop mode for an DLB port. By default, all ports use
+ * AUTO_POP. This function must be called before calling rte_event_port_setup()
+ * for the port, but after calling rte_event_dev_configure().
+ *
+ * @note
+ *    The defer_sched vdev arg, which configures all load-balanced ports with
+ *    dequeue_depth == 1 for DEFERRED_POP mode, takes precedence over this
+ *    function.
+ *
+ * @param dev_id
+ *    The identifier of the event device.
+ * @param port_id
+ *    The identifier of the event port.
+ * @param mode
+ *    The token pop mode.
+ *
+ * @return
+ * - 0: Success
+ * - EINVAL: Invalid dev_id, port_id, or mode
+ * - EINVAL: The DLB is not configured, is already running, or the port is
+ *   already setup
+ */
+
+__rte_experimental
+int
+rte_pmd_dlb_set_token_pop_mode(uint8_t dev_id,
+			       uint8_t port_id,
+			       enum dlb_token_pop_mode mode);
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_PMD_DLB_H_ */
diff --git a/drivers/event/dlb/version.map b/drivers/event/dlb/version.map
index 4a76d1d..3338a22 100644
--- a/drivers/event/dlb/version.map
+++ b/drivers/event/dlb/version.map
@@ -1,3 +1,9 @@
 DPDK_21 {
 	local: *;
 };
+
+EXPERIMENTAL {
+	global:
+
+	rte_pmd_dlb_set_token_pop_mode;
+};
-- 
2.6.4