[libcamera-devel] [PATCH v4 2/5] libcamera: request: Add tracepoints

[Paul Elder]

Add and use tracepoints in Request. Requests are core to libcamera
operation, thus detecting delays in their processing is important, and
serves as a good usage example of tracepoints.

Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

---
Changes in v4:
- move enum tp definitions to "header" tp files
  - add them to meson accordingly
- remove cancelled field from request_complete_buffer tracepoint

Changes in v3:
- expand the changelog
- add enum tracepoint values so that request status and buffer status
  are strings instead of ints in the trace
- remove cancelled from all request tracepoints, except complete_buffer
- expand the complete_buffer tracepoint to include information on the
  buffer
- display the address of the request in all tracepoints
- remove tracepoints for add_buffer and find_buffer

Changes in v2:
- remove tracepoints from uvcvideo
- remove comment in changelog that this is only used for demonstration
- use Request pointers instead of feeding the fields manually to the
  tracepoint
---
 .../internal/tracepoints/buffer_enums.tp      |  9 +++
 .../internal/tracepoints/meson.build          |  5 ++
 .../libcamera/internal/tracepoints/request.tp | 68 +++++++++++++++++++
 .../internal/tracepoints/request_enums.tp     |  9 +++
 src/libcamera/request.cpp                     | 11 +++
 5 files changed, 102 insertions(+)
 create mode 100644 include/libcamera/internal/tracepoints/buffer_enums.tp
 create mode 100644 include/libcamera/internal/tracepoints/request.tp
 create mode 100644 include/libcamera/internal/tracepoints/request_enums.tp

diff --git a/include/libcamera/internal/tracepoints/buffer_enums.tp b/include/libcamera/internal/tracepoints/buffer_enums.tp
new file mode 100644
index 00000000..fdbea69a
--- /dev/null
+++ b/include/libcamera/internal/tracepoints/buffer_enums.tp
@@ -0,0 +1,9 @@
+TRACEPOINT_ENUM(
+	libcamera,
+	buffer_status,
+	TP_ENUM_VALUES(
+		ctf_enum_value("FrameSuccess", 0)
+		ctf_enum_value("FrameError", 1)
+		ctf_enum_value("FrameCancelled", 2)
+	)
+)
diff --git a/include/libcamera/internal/tracepoints/meson.build b/include/libcamera/internal/tracepoints/meson.build
index 2dd6733e..fee0758f 100644
--- a/include/libcamera/internal/tracepoints/meson.build
+++ b/include/libcamera/internal/tracepoints/meson.build
@@ -1,4 +1,9 @@
 # SPDX-License-Identifier: CC0-1.0
 
+# enum files must go first
 tracepoint_files = files([
+    'buffer_enums.tp',
+    'request_enums.tp',
+
+    'request.tp',
 ])
diff --git a/include/libcamera/internal/tracepoints/request.tp b/include/libcamera/internal/tracepoints/request.tp
new file mode 100644
index 00000000..dd28a714
--- /dev/null
+++ b/include/libcamera/internal/tracepoints/request.tp
@@ -0,0 +1,68 @@
+#include <libcamera/buffer.h>
+#include <libcamera/request.h>
+
+TRACEPOINT_EVENT_CLASS(
+	libcamera,
+	request,
+	TP_ARGS(
+		libcamera::Request *, req
+	),
+	TP_FIELDS(
+		ctf_integer_hex(uintptr_t, request, reinterpret_cast<uintptr_t>(req))
+		ctf_integer(uint64_t, cookie, req->cookie())
+		ctf_enum(libcamera, request_status, uint32_t, status, req->status())
+	)
+)
+
+TRACEPOINT_EVENT_INSTANCE(
+	libcamera,
+	request,
+	request_construct,
+	TP_ARGS(
+		libcamera::Request *, req
+	)
+)
+
+TRACEPOINT_EVENT_INSTANCE(
+	libcamera,
+	request,
+	request_destroy,
+	TP_ARGS(
+		libcamera::Request *, req
+	)
+)
+
+TRACEPOINT_EVENT_INSTANCE(
+	libcamera,
+	request,
+	request_reuse,
+	TP_ARGS(
+		libcamera::Request *, req
+	)
+)
+
+TRACEPOINT_EVENT_INSTANCE(
+	libcamera,
+	request,
+	request_complete,
+	TP_ARGS(
+		libcamera::Request *, req
+	)
+)
+
+
+TRACEPOINT_EVENT(
+	libcamera,
+	request_complete_buffer,
+	TP_ARGS(
+		libcamera::Request *, req,
+		libcamera::FrameBuffer *, buf
+	),
+	TP_FIELDS(
+		ctf_integer_hex(uintptr_t, request, reinterpret_cast<uintptr_t>(req))
+		ctf_integer(uint64_t, cookie, req->cookie())
+		ctf_integer(int, status, req->status())
+		ctf_integer_hex(uintptr_t, buffer, reinterpret_cast<uintptr_t>(buf))
+		ctf_enum(libcamera, buffer_status, uint32_t, buf_status, buf->metadata().status)
+	)
+)
diff --git a/include/libcamera/internal/tracepoints/request_enums.tp b/include/libcamera/internal/tracepoints/request_enums.tp
new file mode 100644
index 00000000..371f6544
--- /dev/null
+++ b/include/libcamera/internal/tracepoints/request_enums.tp
@@ -0,0 +1,9 @@
+TRACEPOINT_ENUM(
+	libcamera,
+	request_status,
+	TP_ENUM_VALUES(
+		ctf_enum_value("RequestPending", 0)
+		ctf_enum_value("RequestComplete", 1)
+		ctf_enum_value("RequestCancelled", 2)
+	)
+)
diff --git a/src/libcamera/request.cpp b/src/libcamera/request.cpp
index ae8b1660..a68684ef 100644
--- a/src/libcamera/request.cpp
+++ b/src/libcamera/request.cpp
@@ -16,6 +16,7 @@
 
 #include "libcamera/internal/camera_controls.h"
 #include "libcamera/internal/log.h"
+#include "libcamera/internal/tracepoints.h"
 
 /**
  * \file request.h
@@ -85,10 +86,14 @@ Request::Request(Camera *camera, uint64_t cookie)
 	 * \todo: Add a validator for metadata controls.
 	 */
 	metadata_ = new ControlList(controls::controls);
+
+	LIBCAMERA_TRACEPOINT(request_construct, this);
 }
 
 Request::~Request()
 {
+	LIBCAMERA_TRACEPOINT(request_destroy, this);
+
 	delete metadata_;
 	delete controls_;
 	delete validator_;
@@ -106,6 +111,8 @@ Request::~Request()
  */
 void Request::reuse(ReuseFlag flags)
 {
+	LIBCAMERA_TRACEPOINT(request_reuse, this);
+
 	pending_.clear();
 	if (flags & ReuseBuffers) {
 		for (auto pair : bufferMap_) {
@@ -259,6 +266,8 @@ void Request::complete()
 	LOG(Request, Debug)
 		<< "Request has completed - cookie: " << cookie_
 		<< (cancelled_ ? " [Cancelled]" : "");
+
+	LIBCAMERA_TRACEPOINT(request_complete, this);
 }
 
 /**
@@ -276,6 +285,8 @@ void Request::complete()
  */
 bool Request::completeBuffer(FrameBuffer *buffer)
 {
+	LIBCAMERA_TRACEPOINT(request_complete_buffer, this, buffer);
+
 	int ret = pending_.erase(buffer);
 	ASSERT(ret == 1);
 
-- 
2.27.0