[libcamera-devel] [RFC PATCH 2/2] [DO NOT MERGE] libcamera: uvcvideo, request: Add tracepoints

[Paul Elder]

Add and use tracepoints in the uvcvideo pipeline handler and Request.
This is only meant to show how one would create and use tracepoints.

Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>

---
Setting log level is also available. I haven't tested it yet, but in
theory is should Just Work (TM). It looks like you can set log levels on
the event definitions, and not when you emit the events.
---
 .../internal/tracepoints/meson.build          |  2 +
 .../libcamera/internal/tracepoints/request.tp | 91 +++++++++++++++++++
 .../internal/tracepoints/uvcvideo.tp          | 13 +++
 src/libcamera/pipeline/uvcvideo/uvcvideo.cpp  |  3 +
 src/libcamera/request.cpp                     | 16 ++++
 5 files changed, 125 insertions(+)
 create mode 100644 include/libcamera/internal/tracepoints/request.tp
 create mode 100644 include/libcamera/internal/tracepoints/uvcvideo.tp

diff --git a/include/libcamera/internal/tracepoints/meson.build b/include/libcamera/internal/tracepoints/meson.build
index 2dd6733e..3ec53fbc 100644
--- a/include/libcamera/internal/tracepoints/meson.build
+++ b/include/libcamera/internal/tracepoints/meson.build
@@ -1,4 +1,6 @@
 # SPDX-License-Identifier: CC0-1.0
 
 tracepoint_files = files([
+    'request.tp',
+    'uvcvideo.tp',
 ])
diff --git a/include/libcamera/internal/tracepoints/request.tp b/include/libcamera/internal/tracepoints/request.tp
new file mode 100644
index 00000000..c64bbd43
--- /dev/null
+++ b/include/libcamera/internal/tracepoints/request.tp
@@ -0,0 +1,91 @@
+TRACEPOINT_EVENT_CLASS(
+	libcamera,
+	request,
+	TP_ARGS(
+		uint64_t, cookie,
+		int, status,
+		int, cancelled
+	),
+	TP_FIELDS(
+		ctf_integer(uint64_t, cookie, cookie)
+		ctf_integer(int, status, status)
+		ctf_integer(int, cancelled, cancelled)
+	)
+)
+
+TRACEPOINT_EVENT_INSTANCE(
+	libcamera,
+	request,
+	request_construct,
+	TP_ARGS(
+		uint64_t, cookie,
+		int, status,
+		int, cancelled
+	)
+)
+
+TRACEPOINT_EVENT_INSTANCE(
+	libcamera,
+	request,
+	request_deconstruct,
+	TP_ARGS(
+		uint64_t, cookie,
+		int, status,
+		int, cancelled
+	)
+)
+
+TRACEPOINT_EVENT_INSTANCE(
+	libcamera,
+	request,
+	request_reuse,
+	TP_ARGS(
+		uint64_t, cookie,
+		int, status,
+		int, cancelled
+	)
+)
+
+TRACEPOINT_EVENT_INSTANCE(
+	libcamera,
+	request,
+	request_add_buffer,
+	TP_ARGS(
+		uint64_t, cookie,
+		int, status,
+		int, cancelled
+	)
+)
+
+TRACEPOINT_EVENT_INSTANCE(
+	libcamera,
+	request,
+	request_find_buffer,
+	TP_ARGS(
+		uint64_t, cookie,
+		int, status,
+		int, cancelle
+	)
+)
+
+TRACEPOINT_EVENT_INSTANCE(
+	libcamera,
+	request,
+	request_complete,
+	TP_ARGS(
+		uint64_t, cookie,
+		int, status,
+		int, cancelled
+	)
+)
+
+TRACEPOINT_EVENT_INSTANCE(
+	libcamera,
+	request,
+	request_complete_buffer,
+	TP_ARGS(
+		uint64_t, cookie,
+		int, status,
+		int, cancelled
+	)
+)
diff --git a/include/libcamera/internal/tracepoints/uvcvideo.tp b/include/libcamera/internal/tracepoints/uvcvideo.tp
new file mode 100644
index 00000000..61592ce5
--- /dev/null
+++ b/include/libcamera/internal/tracepoints/uvcvideo.tp
@@ -0,0 +1,13 @@
+TRACEPOINT_EVENT_CLASS(
+	libcamera,
+	uvcvideo,
+	TP_ARGS(),
+	TP_FIELDS()
+)
+
+TRACEPOINT_EVENT_INSTANCE(
+	libcamera,
+	uvcvideo,
+	uvcvideo_contruct,
+	TP_ARGS()
+)
diff --git a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
index 8ec0dac1..bc01a78c 100644
--- a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
+++ b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
@@ -27,6 +27,8 @@
 #include "libcamera/internal/v4l2_controls.h"
 #include "libcamera/internal/v4l2_videodevice.h"
 
+#include "libcamera/internal/tracepoints.h"
+
 namespace libcamera {
 
 LOG_DEFINE_CATEGORY(UVC)
@@ -171,6 +173,7 @@ CameraConfiguration::Status UVCCameraConfiguration::validate()
 PipelineHandlerUVC::PipelineHandlerUVC(CameraManager *manager)
 	: PipelineHandler(manager)
 {
+	LIBCAMERA_TRACEPOINT(uvcvideo_contruct);
 }
 
 CameraConfiguration *PipelineHandlerUVC::generateConfiguration(Camera *camera,
diff --git a/src/libcamera/request.cpp b/src/libcamera/request.cpp
index ae8b1660..74c1a7b0 100644
--- a/src/libcamera/request.cpp
+++ b/src/libcamera/request.cpp
@@ -17,6 +17,8 @@
 #include "libcamera/internal/camera_controls.h"
 #include "libcamera/internal/log.h"
 
+#include "libcamera/internal/tracepoints.h"
+
 /**
  * \file request.h
  * \brief Describes a frame capture request to be processed by a camera
@@ -85,10 +87,14 @@ Request::Request(Camera *camera, uint64_t cookie)
 	 * \todo: Add a validator for metadata controls.
 	 */
 	metadata_ = new ControlList(controls::controls);
+
+	LIBCAMERA_TRACEPOINT(request_construct, cookie_, status_, cancelled_);
 }
 
 Request::~Request()
 {
+	LIBCAMERA_TRACEPOINT(request_deconstruct, cookie_, status_, cancelled_);
+
 	delete metadata_;
 	delete controls_;
 	delete validator_;
@@ -106,6 +112,8 @@ Request::~Request()
  */
 void Request::reuse(ReuseFlag flags)
 {
+	LIBCAMERA_TRACEPOINT(request_reuse, cookie_, status_, cancelled_);
+
 	pending_.clear();
 	if (flags & ReuseBuffers) {
 		for (auto pair : bufferMap_) {
@@ -167,6 +175,8 @@ void Request::reuse(ReuseFlag flags)
  */
 int Request::addBuffer(const Stream *stream, FrameBuffer *buffer)
 {
+	LIBCAMERA_TRACEPOINT(request_add_buffer, cookie_, status_, cancelled_);
+
 	if (!stream) {
 		LOG(Request, Error) << "Invalid stream reference";
 		return -EINVAL;
@@ -202,6 +212,8 @@ int Request::addBuffer(const Stream *stream, FrameBuffer *buffer)
  */
 FrameBuffer *Request::findBuffer(const Stream *stream) const
 {
+	LIBCAMERA_TRACEPOINT(request_find_buffer, cookie_, status_, cancelled_);
+
 	const auto it = bufferMap_.find(stream);
 	if (it == bufferMap_.end())
 		return nullptr;
@@ -253,6 +265,8 @@ FrameBuffer *Request::findBuffer(const Stream *stream) const
  */
 void Request::complete()
 {
+	LIBCAMERA_TRACEPOINT(request_complete, cookie_, status_, cancelled_);
+
 	ASSERT(!hasPendingBuffers());
 	status_ = cancelled_ ? RequestCancelled : RequestComplete;
 
@@ -276,6 +290,8 @@ void Request::complete()
  */
 bool Request::completeBuffer(FrameBuffer *buffer)
 {
+	LIBCAMERA_TRACEPOINT(request_complete_buffer, cookie_, status_, cancelled_);
+
 	int ret = pending_.erase(buffer);
 	ASSERT(ret == 1);
 
-- 
2.27.0