[libcamera-devel] [PATCH v3 2/6] 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>

---
I wasn't sure what the best way to handle the FrameBuffer enum in the tp
file... should it go in a separate file? Will we ever need to use the
FrameBuffer status enum in other tracepoints? If we do, it can't be
defined multiple times, so it'll have to go in its own tp file, and in
the meson tp file list it will have to go first. I guess that's the
drawback of concating all the tp files together...

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/meson.build          |  1 +
 .../libcamera/internal/tracepoints/request.tp | 90 +++++++++++++++++++
 src/libcamera/request.cpp                     | 11 +++
 3 files changed, 102 insertions(+)
 create mode 100644 include/libcamera/internal/tracepoints/request.tp

diff --git a/include/libcamera/internal/tracepoints/meson.build b/include/libcamera/internal/tracepoints/meson.build
index 2dd6733e..8410c205 100644
--- a/include/libcamera/internal/tracepoints/meson.build
+++ b/include/libcamera/internal/tracepoints/meson.build
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: CC0-1.0
 
 tracepoint_files = files([
+    'request.tp',
 ])
diff --git a/include/libcamera/internal/tracepoints/request.tp b/include/libcamera/internal/tracepoints/request.tp
new file mode 100644
index 00000000..92308dcd
--- /dev/null
+++ b/include/libcamera/internal/tracepoints/request.tp
@@ -0,0 +1,90 @@
+#include <libcamera/buffer.h>
+#include <libcamera/request.h>
+
+TRACEPOINT_ENUM(
+	libcamera,
+	request_status,
+	TP_ENUM_VALUES(
+		ctf_enum_value("RequestPending", 0)
+		ctf_enum_value("RequestComplete", 1)
+		ctf_enum_value("RequestCancelled", 2)
+	)
+)
+
+TRACEPOINT_ENUM(
+	libcamera,
+	buffer_status,
+	TP_ENUM_VALUES(
+		ctf_enum_value("FrameSuccess", 0)
+		ctf_enum_value("FrameError", 1)
+		ctf_enum_value("FrameCancelled", 2)
+	)
+)
+
+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,
+		int, cancelled,
+		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(int, cancelled, cancelled)
+		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/src/libcamera/request.cpp b/src/libcamera/request.cpp
index ae8b1660..d1b43697 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, cancelled_, buffer);
+
 	int ret = pending_.erase(buffer);
 	ASSERT(ret == 1);
 
-- 
2.27.0