[PATCH v3] ethdev: optimize the activation of fast-path tracepoints

[Adel Belkhiri]

From: Adel Belkhiri <adel.belkhiri at polymtl.ca>

Split the tracepoints rte_ethdev_trace_rx_burst and
rte_eth_trace_call_rx_callbacks into two separate ones
for empty and non-empty calls to avoid saturating
quickly the trace buffer.

Signed-off-by: Adel Belkhiri <adel.belkhiri at polymtl.ca>
---
 .mailmap                               |  1 +
 doc/guides/rel_notes/release_24_11.rst |  2 ++
 lib/ethdev/ethdev_private.c            |  8 ++++++--
 lib/ethdev/ethdev_trace_points.c       | 14 ++++++++++----
 lib/ethdev/rte_ethdev.h                |  5 ++++-
 lib/ethdev/rte_ethdev_trace_fp.h       | 23 +++++++++++++++++++++--
 lib/ethdev/version.map                 |  7 ++++++-
 7 files changed, 50 insertions(+), 10 deletions(-)

diff --git a/.mailmap b/.mailmap
index 4a508bafad..e86241dced 100644
--- a/.mailmap
+++ b/.mailmap
@@ -16,6 +16,7 @@ Abraham Tovar <abrahamx.tovar at intel.com>
 Adam Bynes <adambynes at outlook.com>
 Adam Dybkowski <adamx.dybkowski at intel.com>
 Adam Ludkiewicz <adam.ludkiewicz at intel.com>
+Adel Belkhiri <adel.belkhiri at polymtl.ca>
 Adham Masarwah <adham at nvidia.com> <adham at mellanox.com>
 Adrian Moreno <amorenoz at redhat.com>
 Adrian Pielech <adrian.pielech at intel.com>
diff --git a/doc/guides/rel_notes/release_24_11.rst b/doc/guides/rel_notes/release_24_11.rst
index 0ff70d9057..b7c3ac4054 100644
--- a/doc/guides/rel_notes/release_24_11.rst
+++ b/doc/guides/rel_notes/release_24_11.rst
@@ -68,6 +68,8 @@ Removed Items
    Also, make sure to start the actual text at the margin.
    =======================================================
 
+* ethdev: Removed the __rte_ethdev_trace_rx_burst symbol, as the corresponding
+  tracepoint was split into two separate ones for empty and non-empty calls.
 
 API Changes
 -----------
diff --git a/lib/ethdev/ethdev_private.c b/lib/ethdev/ethdev_private.c
index 626524558a..eed8c78747 100644
--- a/lib/ethdev/ethdev_private.c
+++ b/lib/ethdev/ethdev_private.c
@@ -298,8 +298,12 @@ rte_eth_call_rx_callbacks(uint16_t port_id, uint16_t queue_id,
 		cb = cb->next;
 	}
 
-	rte_eth_trace_call_rx_callbacks(port_id, queue_id, (void **)rx_pkts,
-					nb_rx, nb_pkts);
+	if (unlikely(nb_rx))
+		rte_eth_trace_call_rx_callbacks_nonempty(port_id, queue_id, (void **)rx_pkts,
+						nb_rx, nb_pkts);
+	else
+		rte_eth_trace_call_rx_callbacks_empty(port_id, queue_id, (void **)rx_pkts,
+						nb_pkts);
 
 	return nb_rx;
 }
diff --git a/lib/ethdev/ethdev_trace_points.c b/lib/ethdev/ethdev_trace_points.c
index 99e04f5893..6ecbee289b 100644
--- a/lib/ethdev/ethdev_trace_points.c
+++ b/lib/ethdev/ethdev_trace_points.c
@@ -25,14 +25,20 @@ RTE_TRACE_POINT_REGISTER(rte_ethdev_trace_stop,
 RTE_TRACE_POINT_REGISTER(rte_ethdev_trace_close,
 	lib.ethdev.close)
 
-RTE_TRACE_POINT_REGISTER(rte_ethdev_trace_rx_burst,
-	lib.ethdev.rx.burst)
+RTE_TRACE_POINT_REGISTER(rte_ethdev_trace_rx_burst_empty,
+	lib.ethdev.rx.burst.empty)
+
+RTE_TRACE_POINT_REGISTER(rte_ethdev_trace_rx_burst_nonempty,
+	lib.ethdev.rx.burst.nonempty)
 
 RTE_TRACE_POINT_REGISTER(rte_ethdev_trace_tx_burst,
 	lib.ethdev.tx.burst)
 
-RTE_TRACE_POINT_REGISTER(rte_eth_trace_call_rx_callbacks,
-	lib.ethdev.call_rx_callbacks)
+RTE_TRACE_POINT_REGISTER(rte_eth_trace_call_rx_callbacks_empty,
+	lib.ethdev.call_rx_callbacks.empty)
+
+RTE_TRACE_POINT_REGISTER(rte_eth_trace_call_rx_callbacks_nonempty,
+	lib.ethdev.call_rx_callbacks.nonempty)
 
 RTE_TRACE_POINT_REGISTER(rte_eth_trace_call_tx_callbacks,
 	lib.ethdev.call_tx_callbacks)
diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h
index 548fada1c7..eef254c463 100644
--- a/lib/ethdev/rte_ethdev.h
+++ b/lib/ethdev/rte_ethdev.h
@@ -6132,7 +6132,10 @@ rte_eth_rx_burst(uint16_t port_id, uint16_t queue_id,
 	}
 #endif
 
-	rte_ethdev_trace_rx_burst(port_id, queue_id, (void **)rx_pkts, nb_rx);
+	if (unlikely(nb_rx))
+		rte_ethdev_trace_rx_burst_nonempty(port_id, queue_id, (void **)rx_pkts, nb_rx);
+	else
+		rte_ethdev_trace_rx_burst_empty(port_id, queue_id, (void **)rx_pkts);
 	return nb_rx;
 }
 
diff --git a/lib/ethdev/rte_ethdev_trace_fp.h b/lib/ethdev/rte_ethdev_trace_fp.h
index 40b6e4756b..d23865996a 100644
--- a/lib/ethdev/rte_ethdev_trace_fp.h
+++ b/lib/ethdev/rte_ethdev_trace_fp.h
@@ -18,7 +18,16 @@ extern "C" {
 #include <rte_trace_point.h>
 
 RTE_TRACE_POINT_FP(
-	rte_ethdev_trace_rx_burst,
+	rte_ethdev_trace_rx_burst_empty,
+	RTE_TRACE_POINT_ARGS(uint16_t port_id, uint16_t queue_id,
+		void **pkt_tbl),
+	rte_trace_point_emit_u16(port_id);
+	rte_trace_point_emit_u16(queue_id);
+	rte_trace_point_emit_ptr(pkt_tbl);
+)
+
+RTE_TRACE_POINT_FP(
+	rte_ethdev_trace_rx_burst_nonempty,
 	RTE_TRACE_POINT_ARGS(uint16_t port_id, uint16_t queue_id,
 		void **pkt_tbl, uint16_t nb_rx),
 	rte_trace_point_emit_u16(port_id);
@@ -38,7 +47,17 @@ RTE_TRACE_POINT_FP(
 )
 
 RTE_TRACE_POINT_FP(
-	rte_eth_trace_call_rx_callbacks,
+	rte_eth_trace_call_rx_callbacks_empty,
+	RTE_TRACE_POINT_ARGS(uint16_t port_id, uint16_t queue_id,
+		void **rx_pkts, uint16_t nb_pkts),
+	rte_trace_point_emit_u16(port_id);
+	rte_trace_point_emit_u16(queue_id);
+	rte_trace_point_emit_ptr(rx_pkts);
+	rte_trace_point_emit_u16(nb_pkts);
+)
+
+RTE_TRACE_POINT_FP(
+	rte_eth_trace_call_rx_callbacks_nonempty,
 	RTE_TRACE_POINT_ARGS(uint16_t port_id, uint16_t queue_id,
 		void **rx_pkts, uint16_t nb_rx, uint16_t nb_pkts),
 	rte_trace_point_emit_u16(port_id);
diff --git a/lib/ethdev/version.map b/lib/ethdev/version.map
index 1669055ca5..f6aca95069 100644
--- a/lib/ethdev/version.map
+++ b/lib/ethdev/version.map
@@ -207,7 +207,6 @@ EXPERIMENTAL {
 	rte_flow_dev_dump;
 
 	# added in 20.05
-	__rte_ethdev_trace_rx_burst;
 	__rte_ethdev_trace_tx_burst;
 	rte_flow_get_aged_flows;
 
@@ -325,6 +324,12 @@ EXPERIMENTAL {
 	rte_flow_template_table_resizable;
 	rte_flow_template_table_resize;
 	rte_flow_template_table_resize_complete;
+
+	# added in 24.11
+	__rte_ethdev_trace_rx_burst_empty;
+	__rte_ethdev_trace_rx_burst_nonempty;
+	__rte_eth_trace_call_rx_callbacks_empty;
+	__rte_eth_trace_call_rx_callbacks_nonempty;
 };
 
 INTERNAL {
-- 
2.34.1