| Message ID | 20200323142205.28342-6-laurent.pinchart@ideasonboard.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series |
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| Related | show |
Hi Laurent, On 23/03/2020 14:21, Laurent Pinchart wrote: > To avoid blocking the camera manager for a long amount of time, move > capture event processing to the main thread. Captured buffers are added > to a queue and an event is posted to the main window to signal > availability of a buffer. > Is the 'queue' necessary? Could the buffers not be passed through the event? > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > --- > src/qcam/main_window.cpp | 54 +++++++++++++++++++++++++++++++++++++++- > src/qcam/main_window.h | 8 ++++++ > 2 files changed, 61 insertions(+), 1 deletion(-) > > diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp > index 354a53367d0f..afd8b9c413f5 100644 > --- a/src/qcam/main_window.cpp > +++ b/src/qcam/main_window.cpp > @@ -19,6 +19,7 @@ > #include <QImage> > #include <QImageWriter> > #include <QInputDialog> > +#include <QMutexLocker> > #include <QStandardPaths> > #include <QTimer> > #include <QToolBar> > @@ -31,6 +32,21 @@ > > using namespace libcamera; > > +class CaptureEvent : public QEvent > +{ > +public: > + CaptureEvent() > + : QEvent(type()) > + { > + } > + > + static Type type() > + { > + static int type = QEvent::registerEventType(); > + return static_cast<Type>(type); > + } > +}; > + > MainWindow::MainWindow(CameraManager *cm, const OptionsParser::Options &options) > : options_(options), cm_(cm), allocator_(nullptr), isCapturing_(false) > { > @@ -63,6 +79,16 @@ MainWindow::~MainWindow() > } > } > > +bool MainWindow::event(QEvent *e) > +{ > + if (e->type() == CaptureEvent::type()) { > + processCapture(); > + return true; > + } > + > + return QMainWindow::event(e); > +} > + > int MainWindow::createToolbars() > { > QAction *action; > @@ -343,6 +369,13 @@ void MainWindow::stopCapture() > > config_.reset(); > > + /* > + * A CaptureEvent may have been posted before we stopped the camera, > + * but not processed yet. Clear the queue of done buffers to avoid > + * racing with the event handler. > + */ > + doneQueue_.clear(); > + Do we not need to lock mutex_ here? > titleTimer_.stop(); > setWindowTitle(title_); > } > @@ -371,10 +404,29 @@ void MainWindow::requestComplete(Request *request) > return; > > const std::map<Stream *, FrameBuffer *> &buffers = request->buffers(); > + FrameBuffer *buffer = buffers.begin()->second; > + > + { > + QMutexLocker locker(&mutex_); > + doneQueue_.enqueue(buffer); > + } > + > + QCoreApplication::postEvent(this, new CaptureEvent); > +} > + > +void MainWindow::processCapture() > +{ > + FrameBuffer *buffer; This scoping is to ensure the locker unlocks after the dequeue right? Perhaps a new line between the FrameBuffer declaration and the start of the scope? It looks a bit like some sort of badly defined inline function otherwise :-S > + { > + QMutexLocker locker(&mutex_); > + if (doneQueue_.isEmpty()) > + return; > + > + buffer = doneQueue_.dequeue(); > + } > > framesCaptured_++; > > - FrameBuffer *buffer = buffers.begin()->second; > const FrameMetadata &metadata = buffer->metadata(); > > double fps = metadata.timestamp - lastBufferTime_; > diff --git a/src/qcam/main_window.h b/src/qcam/main_window.h > index 720a3393e3dc..c623120d5894 100644 > --- a/src/qcam/main_window.h > +++ b/src/qcam/main_window.h > @@ -11,7 +11,9 @@ > > #include <QElapsedTimer> > #include <QMainWindow> > +#include <QMutex> > #include <QObject> > +#include <QQueue> > #include <QTimer> > > #include <libcamera/buffer.h> > @@ -40,6 +42,8 @@ public: > MainWindow(CameraManager *cm, const OptionsParser::Options &options); > ~MainWindow(); > > + bool event(QEvent *e) override; > + > private Q_SLOTS: > void quit(); > void updateTitle(); > @@ -57,6 +61,7 @@ private: > int openCamera(); > > void requestComplete(Request *request); > + void processCapture(); > int display(FrameBuffer *buffer); > void queueRequest(FrameBuffer *buffer); > > @@ -78,6 +83,9 @@ private: > uint32_t previousFrames_; > uint32_t framesCaptured_; > > + QMutex mutex_; > + QQueue<FrameBuffer *> doneQueue_; > + > QToolBar *toolbar_; > ViewFinder *viewfinder_; > std::map<int, std::pair<void *, unsigned int>> mappedBuffers_; >
Hi Kieran, On Mon, Mar 23, 2020 at 02:59:08PM +0000, Kieran Bingham wrote: > On 23/03/2020 14:21, Laurent Pinchart wrote: > > To avoid blocking the camera manager for a long amount of time, move > > capture event processing to the main thread. Captured buffers are added > > to a queue and an event is posted to the main window to signal > > availability of a buffer. > > Is the 'queue' necessary? > Could the buffers not be passed through the event? I would then have no way in processCapture() to ignore the event after stopping the camera. I could check isCapturing_, but at least in theory, we could stop and restart and have the pending event generated before stopped delivered after the restart. I think a queue is cleaner as it gives us full control. > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > > --- > > src/qcam/main_window.cpp | 54 +++++++++++++++++++++++++++++++++++++++- > > src/qcam/main_window.h | 8 ++++++ > > 2 files changed, 61 insertions(+), 1 deletion(-) > > > > diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp > > index 354a53367d0f..afd8b9c413f5 100644 > > --- a/src/qcam/main_window.cpp > > +++ b/src/qcam/main_window.cpp > > @@ -19,6 +19,7 @@ > > #include <QImage> > > #include <QImageWriter> > > #include <QInputDialog> > > +#include <QMutexLocker> > > #include <QStandardPaths> > > #include <QTimer> > > #include <QToolBar> > > @@ -31,6 +32,21 @@ > > > > using namespace libcamera; > > > > +class CaptureEvent : public QEvent > > +{ > > +public: > > + CaptureEvent() > > + : QEvent(type()) > > + { > > + } > > + > > + static Type type() > > + { > > + static int type = QEvent::registerEventType(); > > + return static_cast<Type>(type); > > + } > > +}; > > + > > MainWindow::MainWindow(CameraManager *cm, const OptionsParser::Options &options) > > : options_(options), cm_(cm), allocator_(nullptr), isCapturing_(false) > > { > > @@ -63,6 +79,16 @@ MainWindow::~MainWindow() > > } > > } > > > > +bool MainWindow::event(QEvent *e) > > +{ > > + if (e->type() == CaptureEvent::type()) { > > + processCapture(); > > + return true; > > + } > > + > > + return QMainWindow::event(e); > > +} > > + > > int MainWindow::createToolbars() > > { > > QAction *action; > > @@ -343,6 +369,13 @@ void MainWindow::stopCapture() > > > > config_.reset(); > > > > + /* > > + * A CaptureEvent may have been posted before we stopped the camera, > > + * but not processed yet. Clear the queue of done buffers to avoid > > + * racing with the event handler. > > + */ > > + doneQueue_.clear(); > > + > > Do we not need to lock mutex_ here? No, because at this point there can't be any call to MainWindow::requestComplete(), as the camera is stopped. This function, as well as MainWindow::processCapture(), run in the same thread, so they can't run concurrently. > > titleTimer_.stop(); > > setWindowTitle(title_); > > } > > @@ -371,10 +404,29 @@ void MainWindow::requestComplete(Request *request) > > return; > > > > const std::map<Stream *, FrameBuffer *> &buffers = request->buffers(); > > + FrameBuffer *buffer = buffers.begin()->second; > > + > > + { > > + QMutexLocker locker(&mutex_); > > + doneQueue_.enqueue(buffer); > > + } > > + > > + QCoreApplication::postEvent(this, new CaptureEvent); > > +} > > + > > +void MainWindow::processCapture() > > +{ > > + FrameBuffer *buffer; > > This scoping is to ensure the locker unlocks after the dequeue right? Correct. > Perhaps a new line between the FrameBuffer declaration and the start of > the scope? It looks a bit like some sort of badly defined inline > function otherwise :-S OK. > > + { > > + QMutexLocker locker(&mutex_); > > + if (doneQueue_.isEmpty()) > > + return; > > + > > + buffer = doneQueue_.dequeue(); > > + } > > > > framesCaptured_++; > > > > - FrameBuffer *buffer = buffers.begin()->second; > > const FrameMetadata &metadata = buffer->metadata(); > > > > double fps = metadata.timestamp - lastBufferTime_; > > diff --git a/src/qcam/main_window.h b/src/qcam/main_window.h > > index 720a3393e3dc..c623120d5894 100644 > > --- a/src/qcam/main_window.h > > +++ b/src/qcam/main_window.h > > @@ -11,7 +11,9 @@ > > > > #include <QElapsedTimer> > > #include <QMainWindow> > > +#include <QMutex> > > #include <QObject> > > +#include <QQueue> > > #include <QTimer> > > > > #include <libcamera/buffer.h> > > @@ -40,6 +42,8 @@ public: > > MainWindow(CameraManager *cm, const OptionsParser::Options &options); > > ~MainWindow(); > > > > + bool event(QEvent *e) override; > > + > > private Q_SLOTS: > > void quit(); > > void updateTitle(); > > @@ -57,6 +61,7 @@ private: > > int openCamera(); > > > > void requestComplete(Request *request); > > + void processCapture(); > > int display(FrameBuffer *buffer); > > void queueRequest(FrameBuffer *buffer); > > > > @@ -78,6 +83,9 @@ private: > > uint32_t previousFrames_; > > uint32_t framesCaptured_; > > > > + QMutex mutex_; > > + QQueue<FrameBuffer *> doneQueue_; > > + > > QToolBar *toolbar_; > > ViewFinder *viewfinder_; > > std::map<int, std::pair<void *, unsigned int>> mappedBuffers_;
Hi Laurent, On 23/03/2020 16:52, Laurent Pinchart wrote: > Hi Kieran, > > On Mon, Mar 23, 2020 at 02:59:08PM +0000, Kieran Bingham wrote: >> On 23/03/2020 14:21, Laurent Pinchart wrote: >>> To avoid blocking the camera manager for a long amount of time, move >>> capture event processing to the main thread. Captured buffers are added >>> to a queue and an event is posted to the main window to signal >>> availability of a buffer. >> >> Is the 'queue' necessary? >> Could the buffers not be passed through the event? > > I would then have no way in processCapture() to ignore the event after > stopping the camera. I could check isCapturing_, but at least in theory, > we could stop and restart and have the pending event generated before > stopped delivered after the restart. I think a queue is cleaner as it > gives us full control. > Ok, with minors resolved, Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com> >>> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> >>> --- >>> src/qcam/main_window.cpp | 54 +++++++++++++++++++++++++++++++++++++++- >>> src/qcam/main_window.h | 8 ++++++ >>> 2 files changed, 61 insertions(+), 1 deletion(-) >>> >>> diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp >>> index 354a53367d0f..afd8b9c413f5 100644 >>> --- a/src/qcam/main_window.cpp >>> +++ b/src/qcam/main_window.cpp >>> @@ -19,6 +19,7 @@ >>> #include <QImage> >>> #include <QImageWriter> >>> #include <QInputDialog> >>> +#include <QMutexLocker> >>> #include <QStandardPaths> >>> #include <QTimer> >>> #include <QToolBar> >>> @@ -31,6 +32,21 @@ >>> >>> using namespace libcamera; >>> >>> +class CaptureEvent : public QEvent >>> +{ >>> +public: >>> + CaptureEvent() >>> + : QEvent(type()) >>> + { >>> + } >>> + >>> + static Type type() >>> + { >>> + static int type = QEvent::registerEventType(); >>> + return static_cast<Type>(type); >>> + } >>> +}; >>> + >>> MainWindow::MainWindow(CameraManager *cm, const OptionsParser::Options &options) >>> : options_(options), cm_(cm), allocator_(nullptr), isCapturing_(false) >>> { >>> @@ -63,6 +79,16 @@ MainWindow::~MainWindow() >>> } >>> } >>> >>> +bool MainWindow::event(QEvent *e) >>> +{ >>> + if (e->type() == CaptureEvent::type()) { >>> + processCapture(); >>> + return true; >>> + } >>> + >>> + return QMainWindow::event(e); >>> +} >>> + >>> int MainWindow::createToolbars() >>> { >>> QAction *action; >>> @@ -343,6 +369,13 @@ void MainWindow::stopCapture() >>> >>> config_.reset(); >>> >>> + /* >>> + * A CaptureEvent may have been posted before we stopped the camera, >>> + * but not processed yet. Clear the queue of done buffers to avoid >>> + * racing with the event handler. >>> + */ >>> + doneQueue_.clear(); >>> + >> >> Do we not need to lock mutex_ here? > > No, because at this point there can't be any call to > MainWindow::requestComplete(), as the camera is stopped. This function, > as well as MainWindow::processCapture(), run in the same thread, so they > can't run concurrently. > >>> titleTimer_.stop(); >>> setWindowTitle(title_); >>> } >>> @@ -371,10 +404,29 @@ void MainWindow::requestComplete(Request *request) >>> return; >>> >>> const std::map<Stream *, FrameBuffer *> &buffers = request->buffers(); >>> + FrameBuffer *buffer = buffers.begin()->second; >>> + >>> + { >>> + QMutexLocker locker(&mutex_); >>> + doneQueue_.enqueue(buffer); >>> + } >>> + >>> + QCoreApplication::postEvent(this, new CaptureEvent); >>> +} >>> + >>> +void MainWindow::processCapture() >>> +{ >>> + FrameBuffer *buffer; >> >> This scoping is to ensure the locker unlocks after the dequeue right? > > Correct. > >> Perhaps a new line between the FrameBuffer declaration and the start of >> the scope? It looks a bit like some sort of badly defined inline >> function otherwise :-S > > OK. > >>> + { >>> + QMutexLocker locker(&mutex_); >>> + if (doneQueue_.isEmpty()) >>> + return; >>> + >>> + buffer = doneQueue_.dequeue(); >>> + } >>> >>> framesCaptured_++; >>> >>> - FrameBuffer *buffer = buffers.begin()->second; >>> const FrameMetadata &metadata = buffer->metadata(); >>> >>> double fps = metadata.timestamp - lastBufferTime_; >>> diff --git a/src/qcam/main_window.h b/src/qcam/main_window.h >>> index 720a3393e3dc..c623120d5894 100644 >>> --- a/src/qcam/main_window.h >>> +++ b/src/qcam/main_window.h >>> @@ -11,7 +11,9 @@ >>> >>> #include <QElapsedTimer> >>> #include <QMainWindow> >>> +#include <QMutex> >>> #include <QObject> >>> +#include <QQueue> >>> #include <QTimer> >>> >>> #include <libcamera/buffer.h> >>> @@ -40,6 +42,8 @@ public: >>> MainWindow(CameraManager *cm, const OptionsParser::Options &options); >>> ~MainWindow(); >>> >>> + bool event(QEvent *e) override; >>> + >>> private Q_SLOTS: >>> void quit(); >>> void updateTitle(); >>> @@ -57,6 +61,7 @@ private: >>> int openCamera(); >>> >>> void requestComplete(Request *request); >>> + void processCapture(); >>> int display(FrameBuffer *buffer); >>> void queueRequest(FrameBuffer *buffer); >>> >>> @@ -78,6 +83,9 @@ private: >>> uint32_t previousFrames_; >>> uint32_t framesCaptured_; >>> >>> + QMutex mutex_; >>> + QQueue<FrameBuffer *> doneQueue_; >>> + >>> QToolBar *toolbar_; >>> ViewFinder *viewfinder_; >>> std::map<int, std::pair<void *, unsigned int>> mappedBuffers_; >
diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp index 354a53367d0f..afd8b9c413f5 100644 --- a/src/qcam/main_window.cpp +++ b/src/qcam/main_window.cpp @@ -19,6 +19,7 @@ #include <QImage> #include <QImageWriter> #include <QInputDialog> +#include <QMutexLocker> #include <QStandardPaths> #include <QTimer> #include <QToolBar> @@ -31,6 +32,21 @@ using namespace libcamera; +class CaptureEvent : public QEvent +{ +public: + CaptureEvent() + : QEvent(type()) + { + } + + static Type type() + { + static int type = QEvent::registerEventType(); + return static_cast<Type>(type); + } +}; + MainWindow::MainWindow(CameraManager *cm, const OptionsParser::Options &options) : options_(options), cm_(cm), allocator_(nullptr), isCapturing_(false) { @@ -63,6 +79,16 @@ MainWindow::~MainWindow() } } +bool MainWindow::event(QEvent *e) +{ + if (e->type() == CaptureEvent::type()) { + processCapture(); + return true; + } + + return QMainWindow::event(e); +} + int MainWindow::createToolbars() { QAction *action; @@ -343,6 +369,13 @@ void MainWindow::stopCapture() config_.reset(); + /* + * A CaptureEvent may have been posted before we stopped the camera, + * but not processed yet. Clear the queue of done buffers to avoid + * racing with the event handler. + */ + doneQueue_.clear(); + titleTimer_.stop(); setWindowTitle(title_); } @@ -371,10 +404,29 @@ void MainWindow::requestComplete(Request *request) return; const std::map<Stream *, FrameBuffer *> &buffers = request->buffers(); + FrameBuffer *buffer = buffers.begin()->second; + + { + QMutexLocker locker(&mutex_); + doneQueue_.enqueue(buffer); + } + + QCoreApplication::postEvent(this, new CaptureEvent); +} + +void MainWindow::processCapture() +{ + FrameBuffer *buffer; + { + QMutexLocker locker(&mutex_); + if (doneQueue_.isEmpty()) + return; + + buffer = doneQueue_.dequeue(); + } framesCaptured_++; - FrameBuffer *buffer = buffers.begin()->second; const FrameMetadata &metadata = buffer->metadata(); double fps = metadata.timestamp - lastBufferTime_; diff --git a/src/qcam/main_window.h b/src/qcam/main_window.h index 720a3393e3dc..c623120d5894 100644 --- a/src/qcam/main_window.h +++ b/src/qcam/main_window.h @@ -11,7 +11,9 @@ #include <QElapsedTimer> #include <QMainWindow> +#include <QMutex> #include <QObject> +#include <QQueue> #include <QTimer> #include <libcamera/buffer.h> @@ -40,6 +42,8 @@ public: MainWindow(CameraManager *cm, const OptionsParser::Options &options); ~MainWindow(); + bool event(QEvent *e) override; + private Q_SLOTS: void quit(); void updateTitle(); @@ -57,6 +61,7 @@ private: int openCamera(); void requestComplete(Request *request); + void processCapture(); int display(FrameBuffer *buffer); void queueRequest(FrameBuffer *buffer); @@ -78,6 +83,9 @@ private: uint32_t previousFrames_; uint32_t framesCaptured_; + QMutex mutex_; + QQueue<FrameBuffer *> doneQueue_; + QToolBar *toolbar_; ViewFinder *viewfinder_; std::map<int, std::pair<void *, unsigned int>> mappedBuffers_;
To avoid blocking the camera manager for a long amount of time, move capture event processing to the main thread. Captured buffers are added to a queue and an event is posted to the main window to signal availability of a buffer. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> --- src/qcam/main_window.cpp | 54 +++++++++++++++++++++++++++++++++++++++- src/qcam/main_window.h | 8 ++++++ 2 files changed, 61 insertions(+), 1 deletion(-)