[RFC 2/3] eventdev: allow event ports to modified prefetches

[<pbhagavatula@marvell.com>]

From: Pavan Nikhilesh <pbhagavatula@marvell.com>

Some event devices allow prefetch types to be modified at
runtime on an event port.
Add `RTE_EVENT_DEV_CAP_EVENT_PER_PORT_PREFETCH` capability
to indicate that the event device supports this feature.

Add `rte_event_port_prefetch_modify()` API to modify the
prefetch type at runtime.

Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
---
 app/test/test_eventdev.c                    | 61 +++++++++++++++++++--
 doc/guides/prog_guide/eventdev/eventdev.rst | 12 ++++
 lib/eventdev/eventdev_pmd.h                 |  2 +
 lib/eventdev/eventdev_private.c             | 10 ++++
 lib/eventdev/eventdev_trace_points.c        |  3 +
 lib/eventdev/rte_eventdev.h                 | 55 +++++++++++++++++++
 lib/eventdev/rte_eventdev_core.h            |  5 ++
 lib/eventdev/rte_eventdev_trace_fp.h        | 11 +++-
 lib/eventdev/version.map                    |  4 ++
 9 files changed, 157 insertions(+), 6 deletions(-)

diff --git a/app/test/test_eventdev.c b/app/test/test_eventdev.c
index 1fd3d1fa69..af27a9f0ec 100644
--- a/app/test/test_eventdev.c
+++ b/app/test/test_eventdev.c
@@ -1251,7 +1251,8 @@ test_eventdev_profile_switch(void)
 }
 
 static int
-prefetch_test(rte_event_dev_prefetch_type_t prefetch_type, const char *prefetch_name)
+prefetch_test(rte_event_dev_prefetch_type_t prefetch_type, const char *prefetch_name,
+	      uint8_t modify)
 {
 #define NB_EVENTS     1024
 	uint64_t start, total;
@@ -1269,7 +1270,11 @@ prefetch_test(rte_event_dev_prefetch_type_t prefetch_type, const char *prefetch_
 		TEST_ASSERT(rc == 1, "Failed to enqueue event");
 	}
 
-	RTE_SET_USED(prefetch_type);
+	if (modify) {
+		rc = rte_event_port_prefetch_modify(TEST_DEV_ID, 0, prefetch_type);
+		TEST_ASSERT_SUCCESS(rc, "Failed to modify prefetch type");
+	}
+
 	total = 0;
 	while (cnt) {
 		start = rte_rdtsc_precise();
@@ -1301,11 +1306,55 @@ test_eventdev_prefetch_configure(void)
 	rc = rte_event_dev_configure(TEST_DEV_ID, &dev_conf);
 	TEST_ASSERT_SUCCESS(rc, "Failed to configure eventdev");
 
-	rc = prefetch_test(RTE_EVENT_DEV_PREFETCH_NONE, "RTE_EVENT_DEV_PREFETCH_NONE");
-	rc |= prefetch_test(RTE_EVENT_DEV_PREFETCH, "RTE_EVENT_DEV_PREFETCH");
+	rc = prefetch_test(RTE_EVENT_DEV_PREFETCH_NONE, "RTE_EVENT_DEV_PREFETCH_NONE", 0);
+	rc |= prefetch_test(RTE_EVENT_DEV_PREFETCH, "RTE_EVENT_DEV_PREFETCH", 0);
 	if (info.event_dev_cap & RTE_EVENT_DEV_CAP_EVENT_INTELLIGENT_PREFETCH)
 		rc |= prefetch_test(RTE_EVENT_DEV_PREFETCH_INTELLIGENT,
-				    "RTE_EVENT_DEV_PREFETCH_INTELLIGENT");
+				    "RTE_EVENT_DEV_PREFETCH_INTELLIGENT", 0);
+
+	return rc;
+}
+
+static int
+test_eventdev_prefetch_modify(void)
+{
+	struct rte_event_dev_config dev_conf;
+	struct rte_event_queue_conf qcfg;
+	struct rte_event_port_conf pcfg;
+	struct rte_event_dev_info info;
+	int rc;
+
+	rte_event_dev_info_get(TEST_DEV_ID, &info);
+	if ((info.event_dev_cap & RTE_EVENT_DEV_CAP_EVENT_PER_PORT_PREFETCH) == 0)
+		return TEST_SKIPPED;
+
+	devconf_set_default_sane_values(&dev_conf, &info);
+	dev_conf.prefetch_type = RTE_EVENT_DEV_PREFETCH_NONE;
+	rc = rte_event_dev_configure(TEST_DEV_ID, &dev_conf);
+	TEST_ASSERT_SUCCESS(rc, "Failed to configure eventdev");
+
+	rc = rte_event_port_default_conf_get(TEST_DEV_ID, 0, &pcfg);
+	TEST_ASSERT_SUCCESS(rc, "Failed to get port0 default config");
+	rc = rte_event_port_setup(TEST_DEV_ID, 0, &pcfg);
+	TEST_ASSERT_SUCCESS(rc, "Failed to setup port0");
+
+	rc = rte_event_queue_default_conf_get(TEST_DEV_ID, 0, &qcfg);
+	TEST_ASSERT_SUCCESS(rc, "Failed to get queue0 default config");
+	rc = rte_event_queue_setup(TEST_DEV_ID, 0, &qcfg);
+	TEST_ASSERT_SUCCESS(rc, "Failed to setup queue0");
+
+	rc = rte_event_port_link(TEST_DEV_ID, 0, NULL, NULL, 0);
+	TEST_ASSERT(rc == (int)dev_conf.nb_event_queues, "Failed to link port, device %d",
+		    TEST_DEV_ID);
+
+	rc = rte_event_dev_start(TEST_DEV_ID);
+	TEST_ASSERT_SUCCESS(rc, "Failed to start event device");
+
+	rc = prefetch_test(RTE_EVENT_DEV_PREFETCH_NONE, "RTE_EVENT_DEV_PREFETCH_NONE", 1);
+	rc |= prefetch_test(RTE_EVENT_DEV_PREFETCH, "RTE_EVENT_DEV_PREFETCH", 1);
+	if (info.event_dev_cap & RTE_EVENT_DEV_CAP_EVENT_INTELLIGENT_PREFETCH)
+		rc |= prefetch_test(RTE_EVENT_DEV_PREFETCH_INTELLIGENT,
+				    "RTE_EVENT_DEV_PREFETCH_INTELLIGENT", 1);
 
 	return rc;
 }
@@ -1372,6 +1421,8 @@ static struct unit_test_suite eventdev_common_testsuite  = {
 			test_eventdev_profile_switch),
 		TEST_CASE_ST(eventdev_configure_setup, NULL,
 			test_eventdev_prefetch_configure),
+		TEST_CASE_ST(eventdev_configure_setup, eventdev_stop_device,
+			test_eventdev_prefetch_modify),
 		TEST_CASE_ST(eventdev_setup_device, eventdev_stop_device,
 			test_eventdev_link),
 		TEST_CASE_ST(eventdev_setup_device, eventdev_stop_device,
diff --git a/doc/guides/prog_guide/eventdev/eventdev.rst b/doc/guides/prog_guide/eventdev/eventdev.rst
index 89064883b7..8b6085512d 100644
--- a/doc/guides/prog_guide/eventdev/eventdev.rst
+++ b/doc/guides/prog_guide/eventdev/eventdev.rst
@@ -379,6 +379,18 @@ Currently, the following prefetch types are supported:
  * ``RTE_EVENT_DEV_PREFETCH_INTELLIGENT`` - Issue prefetch when dequeue is issued and there are
    no forward progress constraints.
 
+To enable or disable event prefetching at a given event port, the application can use
+``rte_event_port_prefetch_modify()`` API.
+
+.. code-block:: c
+
+   rte_event_port_prefetch_modify(dev_id, port_id, RTE_EVENT_DEV_PREFETCH);
+   // Dequeue events from the event port with normal dequeue() function.
+   rte_event_port_prefetch_modify(dev_id, port_id, RTE_EVENT_DEV_PREFETCH_NONE);
+   // Disable prefetching if thread is about to be scheduled out and issue dequeue() to drain
+   // pending events.
+
+
 Starting the EventDev
 ~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/lib/eventdev/eventdev_pmd.h b/lib/eventdev/eventdev_pmd.h
index 7a5699f14b..d93c11e9f1 100644
--- a/lib/eventdev/eventdev_pmd.h
+++ b/lib/eventdev/eventdev_pmd.h
@@ -184,6 +184,8 @@ struct __rte_cache_aligned rte_eventdev {
 	/**< Pointer to PMD DMA adapter enqueue function. */
 	event_profile_switch_t profile_switch;
 	/**< Pointer to PMD Event switch profile function. */
+	event_prefetch_modify_t prefetch_modify;
+	/**< Pointer to PMD Event port prefetch modify function.  */
 
 	uint64_t reserved_64s[3]; /**< Reserved for future fields */
 	void *reserved_ptrs[3];	  /**< Reserved for future fields */
diff --git a/lib/eventdev/eventdev_private.c b/lib/eventdev/eventdev_private.c
index 017f97ccab..6e8beb29ad 100644
--- a/lib/eventdev/eventdev_private.c
+++ b/lib/eventdev/eventdev_private.c
@@ -96,6 +96,14 @@ dummy_event_port_profile_switch(__rte_unused void *port, __rte_unused uint8_t pr
 	return -EINVAL;
 }
 
+static int
+dummy_event_port_prefetch_modify(__rte_unused void *port,
+				 __rte_unused rte_event_dev_prefetch_type_t prefetch)
+{
+	RTE_EDEV_LOG_ERR("modify prefetch requested for unconfigured event device");
+	return -EINVAL;
+}
+
 void
 event_dev_fp_ops_reset(struct rte_event_fp_ops *fp_op)
 {
@@ -114,6 +122,7 @@ event_dev_fp_ops_reset(struct rte_event_fp_ops *fp_op)
 		.ca_enqueue = dummy_event_crypto_adapter_enqueue,
 		.dma_enqueue = dummy_event_dma_adapter_enqueue,
 		.profile_switch = dummy_event_port_profile_switch,
+		.prefetch_modify = dummy_event_port_prefetch_modify,
 		.data = dummy_data,
 	};
 
@@ -136,5 +145,6 @@ event_dev_fp_ops_set(struct rte_event_fp_ops *fp_op,
 	fp_op->ca_enqueue = dev->ca_enqueue;
 	fp_op->dma_enqueue = dev->dma_enqueue;
 	fp_op->profile_switch = dev->profile_switch;
+	fp_op->prefetch_modify = dev->prefetch_modify;
 	fp_op->data = dev->data->ports;
 }
diff --git a/lib/eventdev/eventdev_trace_points.c b/lib/eventdev/eventdev_trace_points.c
index 8024e07531..e0547d18c6 100644
--- a/lib/eventdev/eventdev_trace_points.c
+++ b/lib/eventdev/eventdev_trace_points.c
@@ -49,6 +49,9 @@ RTE_TRACE_POINT_REGISTER(rte_eventdev_trace_maintain,
 RTE_TRACE_POINT_REGISTER(rte_eventdev_trace_port_profile_switch,
 	lib.eventdev.port.profile.switch)
 
+RTE_TRACE_POINT_REGISTER(rte_eventdev_trace_port_prefetch_modify,
+	lib.eventdev.port.prefetch.modify)
+
 /* Eventdev Rx adapter trace points */
 RTE_TRACE_POINT_REGISTER(rte_eventdev_trace_eth_rx_adapter_create,
 	lib.eventdev.rx.adapter.create)
diff --git a/lib/eventdev/rte_eventdev.h b/lib/eventdev/rte_eventdev.h
index 59c323c8ee..1bc6c48dd3 100644
--- a/lib/eventdev/rte_eventdev.h
+++ b/lib/eventdev/rte_eventdev.h
@@ -470,6 +470,16 @@ struct rte_event;
  * @see rte_event_dev_configure()
  */
 
+#define RTE_EVENT_DEV_CAP_EVENT_PER_PORT_PREFETCH (1ULL << 18)
+/**< Event device supports event prefetching per event port.
+ *
+ * When this flag is set, the event device allows controlling the event
+ * prefetching/pre-scheduling at a event port granularity.
+ *
+ * @see rte_event_dev_configure()
+ * @see rte_event_port_prefetch_modify()
+ */
+
 /* Event device priority levels */
 #define RTE_EVENT_DEV_PRIORITY_HIGHEST   0
 /**< Highest priority level for events and queues.
@@ -708,18 +718,23 @@ typedef enum {
 	RTE_EVENT_DEV_PREFETCH_NONE = 0,
 	/* Disable prefetch across the event device or on a given event port.
 	 * @ref rte_event_dev_config.prefetch_type
+	 * @ref rte_event_port_prefetch_modify()
 	 */
 	RTE_EVENT_DEV_PREFETCH,
 	/* Enable prefetch always across the event device or a given event port.
 	 * @ref rte_event_dev_config.prefetch_type
+	 * @ref rte_event_port_prefetch_modify()
 	 * @see RTE_EVENT_DEV_CAP_EVENT_PREFETCH
+	 * @see RTE_EVENT_DEV_CAP_EVENT_PER_PORT_PREFETCH
 	 */
 	RTE_EVENT_DEV_PREFETCH_INTELLIGENT,
 	/* Enable intelligent prefetch across the event device or a given event port.
 	 * Delay issuing prefetch until there are no forward progress constraints with
 	 * the held flow contexts.
 	 * @ref rte_event_dev_config.prefetch_type
+	 * @ref rte_event_port_prefetch_modify()
 	 * @see RTE_EVENT_DEV_CAP_EVENT_INTELLIGENT_PREFETCH
+	 * @see RTE_EVENT_DEV_CAP_EVENT_PER_PORT_PREFETCH
 	 */
 } rte_event_dev_prefetch_type_t;
 
@@ -2922,6 +2937,46 @@ rte_event_port_profile_switch(uint8_t dev_id, uint8_t port_id, uint8_t profile_i
 	return fp_ops->profile_switch(port, profile_id);
 }
 
+/**
+ * Change the prefetch type to use on an event port.
+ *
+ * This function is used to change the current prefetch type configured
+ * on an event port, the prefetch type can be set to none to disable prefetching.
+ * This effects the subsequent ``rte_event_dequeue_burst`` call.
+ * The event device should support RTE_EVENT_DEV_CAP_PER_PORT_PREFETCH capability.
+ *
+ * @param dev_id
+ *   The identifier of the device.
+ * @param port_id
+ *   The identifier of the event port.
+ * @param type
+ *   The prefetch type to use on the event port.
+ * @return
+ *  - 0 on success.
+ *  - -EINVAL if *dev_id*,  *port_id*, or *type* is invalid.
+ *  - -ENOTSUP if the device doesn't support prefetch or per port prefetch.
+ */
+static inline int
+rte_event_port_prefetch_modify(uint8_t dev_id, uint8_t port_id, rte_event_dev_prefetch_type_t type)
+{
+	const struct rte_event_fp_ops *fp_ops;
+	void *port;
+
+	fp_ops = &rte_event_fp_ops[dev_id];
+	port = fp_ops->data[port_id];
+
+#ifdef RTE_LIBRTE_EVENTDEV_DEBUG
+	if (dev_id >= RTE_EVENT_MAX_DEVS || port_id >= RTE_EVENT_MAX_PORTS_PER_DEV)
+		return -EINVAL;
+
+	if (port == NULL)
+		return -EINVAL;
+#endif
+	rte_eventdev_trace_port_prefetch_modify(dev_id, port_id, type);
+
+	return fp_ops->prefetch_modify(port, type);
+}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/eventdev/rte_eventdev_core.h b/lib/eventdev/rte_eventdev_core.h
index fc8e1556ab..b185fe3654 100644
--- a/lib/eventdev/rte_eventdev_core.h
+++ b/lib/eventdev/rte_eventdev_core.h
@@ -49,6 +49,9 @@ typedef uint16_t (*event_dma_adapter_enqueue_t)(void *port, struct rte_event ev[
 typedef int (*event_profile_switch_t)(void *port, uint8_t profile);
 /**< @internal Switch active link profile on the event port. */
 
+typedef int (*event_prefetch_modify_t)(void *port, rte_event_dev_prefetch_type_t prefetch_type);
+/**< @internal Modify prefetch type on the event port. */
+
 struct __rte_cache_aligned rte_event_fp_ops {
 	void **data;
 	/**< points to array of internal port data pointers */
@@ -76,6 +79,8 @@ struct __rte_cache_aligned rte_event_fp_ops {
 	/**< PMD DMA adapter enqueue function. */
 	event_profile_switch_t profile_switch;
 	/**< PMD Event switch profile function. */
+	event_prefetch_modify_t prefetch_modify;
+	/**< PMD Event port prefetch switch. */
 	uintptr_t reserved[4];
 };
 
diff --git a/lib/eventdev/rte_eventdev_trace_fp.h b/lib/eventdev/rte_eventdev_trace_fp.h
index 04d510ad00..06bfd48011 100644
--- a/lib/eventdev/rte_eventdev_trace_fp.h
+++ b/lib/eventdev/rte_eventdev_trace_fp.h
@@ -8,7 +8,7 @@
 /**
  * @file
  *
- * API for ethdev trace support
+ * API for eventdev trace support
  */
 
 #ifdef __cplusplus
@@ -54,6 +54,15 @@ RTE_TRACE_POINT_FP(
 	rte_trace_point_emit_u8(profile);
 )
 
+RTE_TRACE_POINT_FP(
+	rte_eventdev_trace_port_prefetch_modify,
+	RTE_TRACE_POINT_ARGS(uint8_t dev_id, uint8_t port_id,
+			     int type),
+	rte_trace_point_emit_u8(dev_id);
+	rte_trace_point_emit_u8(port_id);
+	rte_trace_point_emit_int(type);
+)
+
 RTE_TRACE_POINT_FP(
 	rte_eventdev_trace_eth_tx_adapter_enqueue,
 	RTE_TRACE_POINT_ARGS(uint8_t dev_id, uint8_t port_id, void *ev_table,
diff --git a/lib/eventdev/version.map b/lib/eventdev/version.map
index 4947bb4ec6..62c0563fb1 100644
--- a/lib/eventdev/version.map
+++ b/lib/eventdev/version.map
@@ -147,6 +147,10 @@ EXPERIMENTAL {
 	rte_event_port_profile_unlink;
 	rte_event_port_profile_links_get;
 	__rte_eventdev_trace_port_profile_switch;
+
+	# added in 24.11
+	rte_event_port_prefetch_modify;
+	__rte_eventdev_trace_port_prefetch_modify;
 };
 
 INTERNAL {
-- 
2.25.1