[libcamera-devel] [PATCH v3 1/6] libcamera: tracing: Implement tracing infrastructure
Kieran Bingham
kieran.bingham at ideasonboard.com
Thu Oct 29 11:30:51 CET 2020
Hi Paul,
On 29/10/2020 10:16, Paul Elder wrote:
> Implement tracing infrastructure in libcamera. It takes .tp files, as
> required by lttng, and generates a tracepoint header and C file, as lttng
> requires. meson is updated accordingly to get it to compile with the
> rest of libcamera. Update the documentation accordingly.
>
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
>
> ---
> Changes in v3:
> - rename the tracepoints header generateor in meson
> - add protection against accidental unused variables when tracing is
> disabled
> - make gen-tp-header.py read files as utf-8
> - add macros LIBCAMERA_TRACEPOINT_IPA_{BEGIN,END}
>
> Changes in v2:
> - move header.tmpl to tracepoints.h.in
> - rename meson option 'tracepoints' to 'tracing'
> - make sure C++ objects work in tracepoint arguments
> - rename generate_header.py to gen-tp-header.py
> ---
> Documentation/Doxyfile.in | 2 +
> README.rst | 3 +
> include/libcamera/internal/meson.build | 9 +++
> include/libcamera/internal/tracepoints.h.in | 62 +++++++++++++++++++
> .../internal/tracepoints/meson.build | 4 ++
> meson.build | 3 +
> meson_options.txt | 5 ++
> src/libcamera/meson.build | 7 +++
> src/libcamera/tracepoints.cpp | 10 +++
> utils/meson.build | 1 +
> utils/tracepoints/gen-tp-header.py | 38 ++++++++++++
> utils/tracepoints/meson.build | 5 ++
> 12 files changed, 149 insertions(+)
> create mode 100644 include/libcamera/internal/tracepoints.h.in
> create mode 100644 include/libcamera/internal/tracepoints/meson.build
> create mode 100644 src/libcamera/tracepoints.cpp
> create mode 100644 utils/tracepoints/gen-tp-header.py
> create mode 100644 utils/tracepoints/meson.build
>
> diff --git a/Documentation/Doxyfile.in b/Documentation/Doxyfile.in
> index 5ccd0d05..9a7a3fb4 100644
> --- a/Documentation/Doxyfile.in
> +++ b/Documentation/Doxyfile.in
> @@ -842,6 +842,8 @@ EXCLUDE = @TOP_SRCDIR@/include/libcamera/span.h \
> @TOP_SRCDIR@/src/libcamera/ipa_ipc_unixsocket.cpp \
> @TOP_SRCDIR@/src/libcamera/pipeline/ \
> @TOP_SRCDIR@/src/libcamera/proxy/ \
> + @TOP_SRCDIR@/src/libcamera/tracepoints.cpp \
> + @TOP_BUILDDIR@/include/libcamera/internal/tracepoints.h \
> @TOP_BUILDDIR@/include/libcamera/ipa/ \
> @TOP_BUILDDIR@/src/libcamera/proxy/
>
> diff --git a/README.rst b/README.rst
> index fc8f4948..5c4b6989 100644
> --- a/README.rst
> +++ b/README.rst
> @@ -81,6 +81,9 @@ for gstreamer: [optional]
> for qcam: [optional]
> qtbase5-dev libqt5core5a libqt5gui5 libqt5widgets5 qttools5-dev-tools libtiff-dev
>
> +for tracing with lttng: [optional]
> + lttng-ust-dev python3-jinja2
> +
> Using GStreamer plugin
> ~~~~~~~~~~~~~~~~~~~~~~
>
> diff --git a/include/libcamera/internal/meson.build b/include/libcamera/internal/meson.build
> index 8dd744fd..592635a9 100644
> --- a/include/libcamera/internal/meson.build
> +++ b/include/libcamera/internal/meson.build
> @@ -1,5 +1,14 @@
> # SPDX-License-Identifier: CC0-1.0
>
> +subdir('tracepoints')
> +
> +libcamera_tracepoint_header = custom_target(
> + 'tp_header',
> + input: [ 'tracepoints.h.in', tracepoint_files ],
> + output: 'tracepoints.h',
> + command: [ gen_tracepoints_header, '@OUTPUT@', '@INPUT@' ],
> +)
> +
> libcamera_internal_headers = files([
> 'byte_stream_buffer.h',
> 'camera_controls.h',
> diff --git a/include/libcamera/internal/tracepoints.h.in b/include/libcamera/internal/tracepoints.h.in
> new file mode 100644
> index 00000000..830c61d7
> --- /dev/null
> +++ b/include/libcamera/internal/tracepoints.h.in
> @@ -0,0 +1,62 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) {{year}}, Google Inc.
> + *
> + * tracepoints.h - Tracepoints with lttng
> + *
> + * This file is auto-generated. Do not edit.
> + */
> +#ifndef __LIBCAMERA_INTERNAL_TRACEPOINTS_H__
> +#define __LIBCAMERA_INTERNAL_TRACEPOINTS_H__
> +
> +#if HAVE_TRACING
> +#define LIBCAMERA_TRACEPOINT(...) tracepoint(libcamera, __VA_ARGS__)
> +
> +#define LIBCAMERA_TRACEPOINT_IPA_BEGIN(pipe, func) \
> +tracepoint(libcamera, ipa_call_begin, #pipe, #func)
> +
> +#define LIBCAMERA_TRACEPOINT_IPA_END(pipe, func) \
> +tracepoint(libcamera, ipa_call_end, #pipe, #func)
> +
> +#else
> +
> +namespace {
> +
> +template <typename ...Args>
> +inline void unused([[maybe_unused]] Args&& ...args)
> +{
> +}
Do you need this ununsed()?
> +
> +} /* namespace */
> +
> +#define LIBCAMERA_TRACEPOINT(category, ...) unused(__VA_ARGS__)
You could just define the following to declare that they don't do anything:
#define LIBCAMERA_TRACEPOINT(category, ...) do { } while (0)
#define LIBCAMERA_TRACEPOINT_IPA_BEGIN(pipe, func) do { } while (0)
#define LIBCAMERA_TRACEPOINT_IPA_END(pipe, func) do { } while (0)
But perhaps that's the C developer approach.
There's no requirement to change this by the way, I'm only wondering if
removing the template would be faster at build time.
Otherwise, at least simplifying the function to
inline void unused(void)
{
}
and not passing the arguments, would remove the need for any templating
also.
But that's fairly minor, and the rest looks reasonable to me.
Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> +
> +#define LIBCAMERA_TRACEPOINT_IPA_BEGIN(pipe, func) unused(#pipe, #func)
> +
> +#define LIBCAMERA_TRACEPOINT_IPA_END(pipe, func) unused(#pipe, #func)
> +
> +#endif /* HAVE_TRACING */
> +
> +#endif /* __LIBCAMERA_INTERNAL_TRACEPOINTS_H__ */
> +
> +
> +#if HAVE_TRACING
> +
> +#undef TRACEPOINT_PROVIDER
> +#define TRACEPOINT_PROVIDER libcamera
> +
> +#undef TRACEPOINT_INCLUDE
> +#define TRACEPOINT_INCLUDE "{{path}}"
> +
> +#if !defined(INCLUDE_LIBCAMERA_INTERNAL_TRACEPOINTS_TP_H) || defined(TRACEPOINT_HEADER_MULTI_READ)
> +#define INCLUDE_LIBCAMERA_INTERNAL_TRACEPOINTS_TP_H
> +
> +#include <lttng/tracepoint.h>
> +
> +{{source}}
> +
> +#endif /* INCLUDE_LIBCAMERA_INTERNAL_TRACEPOINTS_TP_H */
> +
> +#include <lttng/tracepoint-event.h>
> +
> +#endif /* HAVE_TRACING */
> diff --git a/include/libcamera/internal/tracepoints/meson.build b/include/libcamera/internal/tracepoints/meson.build
> new file mode 100644
> index 00000000..2dd6733e
> --- /dev/null
> +++ b/include/libcamera/internal/tracepoints/meson.build
> @@ -0,0 +1,4 @@
> +# SPDX-License-Identifier: CC0-1.0
> +
> +tracepoint_files = files([
> +])
> diff --git a/meson.build b/meson.build
> index e6f6c84a..55cf36e1 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -108,6 +108,9 @@ libcamera_includes = include_directories('include')
> # Sub-directories fill py_modules with their dependencies.
> py_modules = []
>
> +# Libraries used by multiple components
> +liblttng = cc.find_library('lttng-ust', required : get_option('tracing'))
> +
> # Utilities are parsed first to provide support for other components.
> subdir('utils')
>
> diff --git a/meson_options.txt b/meson_options.txt
> index 7f7b3e59..53f2675e 100644
> --- a/meson_options.txt
> +++ b/meson_options.txt
> @@ -28,6 +28,11 @@ option('test',
> type : 'boolean',
> description: 'Compile and include the tests')
>
> +option('tracing',
> + type : 'feature',
> + value : 'auto',
> + description: 'Enable tracing (based on lttng)')
> +
> option('v4l2',
> type : 'boolean',
> value : false,
> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
> index 24f7ea3d..51925bd6 100644
> --- a/src/libcamera/meson.build
> +++ b/src/libcamera/meson.build
> @@ -58,6 +58,7 @@ libcamera_sources = files([
>
> libcamera_sources += libcamera_public_headers
> libcamera_sources += libcamera_generated_ipa_headers
> +libcamera_sources += libcamera_tracepoint_header
>
> includes = [
> libcamera_includes,
> @@ -75,6 +76,11 @@ if libgnutls.found()
> config_h.set('HAVE_GNUTLS', 1)
> endif
>
> +if liblttng.found()
> + config_h.set('HAVE_TRACING', 1)
> + libcamera_sources += files(['tracepoints.cpp'])
> +endif
> +
> if libudev.found()
> config_h.set('HAVE_LIBUDEV', 1)
> libcamera_sources += files([
> @@ -117,6 +123,7 @@ libcamera_deps = [
> libatomic,
> libdl,
> libgnutls,
> + liblttng,
> libudev,
> dependency('threads'),
> ]
> diff --git a/src/libcamera/tracepoints.cpp b/src/libcamera/tracepoints.cpp
> new file mode 100644
> index 00000000..0173b75a
> --- /dev/null
> +++ b/src/libcamera/tracepoints.cpp
> @@ -0,0 +1,10 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2020, Google Inc.
> + *
> + * tracepoints.cpp - Tracepoints with lttng
> + */
> +#define TRACEPOINT_CREATE_PROBES
> +#define TRACEPOINT_DEFINE
> +
> +#include "libcamera/internal/tracepoints.h"
> diff --git a/utils/meson.build b/utils/meson.build
> index 383d5285..8e28ada7 100644
> --- a/utils/meson.build
> +++ b/utils/meson.build
> @@ -2,6 +2,7 @@
>
> subdir('ipc')
> subdir('ipu3')
> +subdir('tracepoints')
>
> ## Code generation
> py_modules += ['yaml']
> diff --git a/utils/tracepoints/gen-tp-header.py b/utils/tracepoints/gen-tp-header.py
> new file mode 100644
> index 00000000..9500e474
> --- /dev/null
> +++ b/utils/tracepoints/gen-tp-header.py
> @@ -0,0 +1,38 @@
> +#!/usr/bin/env python3
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +# Copyright (C) 2020, Google Inc.
> +#
> +# Author: Paul Elder <paul.elder at ideasonboard.com>
> +#
> +# gen-tp-header.py - Generate header file to contain lttng tracepoints
> +
> +import datetime
> +import jinja2
> +import os
> +import sys
> +
> +def main(argv):
> + if len(argv) < 3:
> + print(f'Usage: {argv[0]} output template tp_files...')
> + return 1
> +
> + output = argv[1]
> + template = argv[2]
> +
> + year = datetime.datetime.now().year
> + path = output.replace('include/', '', 1)
> +
> + source = ''
> + for fname in argv[3:]:
> + source += open(fname, 'r', encoding='utf-8').read() + '\n\n'
> +
> + template = jinja2.Template(open(template, 'r').read())
> + string = template.render(year=year, path=path, source=source)
> +
> + f = open(output, 'w').write(string)
> +
> + return 0
> +
> +
> +if __name__ == '__main__':
> + sys.exit(main(sys.argv))
> diff --git a/utils/tracepoints/meson.build b/utils/tracepoints/meson.build
> new file mode 100644
> index 00000000..807230fc
> --- /dev/null
> +++ b/utils/tracepoints/meson.build
> @@ -0,0 +1,5 @@
> +# SPDX-License-Identifier: CC0-1.0
> +
> +py_modules += ['jinja2']
> +
> +gen_tracepoints_header = find_program('./gen-tp-header.py')
>
--
Regards
--
Kieran
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