[libcamera-devel] [PATCH v6 7/7] android: post_processor: Make post processing async
Umang Jain
umang.jain at ideasonboard.com
Sat Oct 23 12:33:02 CEST 2021
Introduce a dedicated worker class derived from libcamera::Thread.
The worker class maintains a queue for post-processing requests
and waits for a post-processing request to become available.
It will process them as per FIFO before de-queuing it from the
queue.
The post processing streams loop in CameraDevice::requestComplete()
is tweaked a bit to better suit asynchronous needs of post processing.
Also, the entire iteration is locked under streamProcessMutex_ which
helps us to queue all the post-processing request at once, before any
of the post-processing completion slot (streamProcessingComplete())
is allowed to run for post-processing requests completing in parallel.
This helps us to manage both synchronous and asynchronous errors
encountered during the entire post processing operation.
This patch also implements a flush() for the PostProcessorWorker
class which is responsible to purge post-processing requests
queued up while a camera is stopping/flushing. It is hooked with
CameraStream::flush(), which isn't used currently but will be
used when we handle flush/stop scenarios in greater detail
subsequently (in a different patchset).
The libcamera request completion handler CameraDevice::requestComplete()
assumes that the request that has just completed is at the front of the
queue. Now that the post-processor runs asynchronously, this isn't true
anymore, a request being post-processed will stay in the queue and a new
libcamera request may complete. Remove that assumption, and use the
request cookie to obtain the Camera3RequestDescriptor.
Signed-off-by: Umang Jain <umang.jain at ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
src/android/camera_device.cpp | 49 +++++------------
src/android/camera_stream.cpp | 101 ++++++++++++++++++++++++++++++++--
src/android/camera_stream.h | 38 ++++++++++++-
3 files changed, 148 insertions(+), 40 deletions(-)
diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
index 3114def0..dc39467b 100644
--- a/src/android/camera_device.cpp
+++ b/src/android/camera_device.cpp
@@ -1026,29 +1026,8 @@ int CameraDevice::processCaptureRequest(camera3_capture_request_t *camera3Reques
void CameraDevice::requestComplete(Request *request)
{
- Camera3RequestDescriptor *descriptor;
- {
- MutexLocker descriptorsLock(descriptorsMutex_);
- ASSERT(!descriptors_.empty());
- descriptor = descriptors_.front().get();
- }
-
- if (descriptor->request_->cookie() != request->cookie()) {
- /*
- * \todo Clarify if the Camera has to be closed on
- * ERROR_DEVICE.
- */
- LOG(HAL, Error)
- << "Out-of-order completion for request "
- << utils::hex(request->cookie());
-
- MutexLocker descriptorsLock(descriptorsMutex_);
- descriptors_.pop();
-
- notifyError(0, nullptr, CAMERA3_MSG_ERROR_DEVICE);
-
- return;
- }
+ Camera3RequestDescriptor *descriptor =
+ reinterpret_cast<Camera3RequestDescriptor *>(request->cookie());
/*
* Prepare the capture result for the Android camera stack.
@@ -1124,12 +1103,16 @@ void CameraDevice::requestComplete(Request *request)
/* Handle post-processing. */
bool needPostProcessing = false;
+ MutexLocker locker(descriptor->streamsProcessMutex_);
+
/*
- * \todo Protect the loop below with streamProcessMutex_ when post
- * processor runs asynchronously.
+ * Queue all the post-processing streams request at once. The completion
+ * slot streamProcessingComplete() can only execute when we are out
+ * this critical section. This helps to handle synchronous errors here
+ * itself.
*/
auto iter = descriptor->pendingStreamsToProcess_.begin();
- while (descriptor->pendingStreamsToProcess_.size() > 0) {
+ while (iter != descriptor->pendingStreamsToProcess_.end()) {
CameraStream *stream = iter->first;
Camera3RequestDescriptor::StreamBuffer *buffer = iter->second;
needPostProcessing = true;
@@ -1151,18 +1134,16 @@ void CameraDevice::requestComplete(Request *request)
}
if (needPostProcessing) {
- /*
- * \todo We will require to check if we failed to queue
- * post-processing requests when we migrate to post-processor
- * running asynchronously.
- *
- * if (descriptor->pendingStreamsToProcess_.size() == 0)
- * completeDescriptor(descriptor);
- */
+ if (descriptor->pendingStreamsToProcess_.size() == 0) {
+ locker.unlock();
+ completeDescriptor(descriptor);
+ }
return;
}
+ locker.unlock();
+
completeDescriptor(descriptor);
}
diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
index 45d0607d..68b916e9 100644
--- a/src/android/camera_stream.cpp
+++ b/src/android/camera_stream.cpp
@@ -99,6 +99,7 @@ int CameraStream::configure()
if (ret)
return ret;
+ worker_ = std::make_unique<PostProcessorWorker>(postProcessor_.get());
postProcessor_->processComplete.connect(
this, [&](Camera3RequestDescriptor::StreamBuffer *streamBuffer,
PostProcessor::Status status) {
@@ -112,6 +113,8 @@ int CameraStream::configure()
cameraDevice_->streamProcessingComplete(streamBuffer,
bufferStatus);
});
+
+ worker_->start();
}
if (type_ == Type::Internal) {
@@ -179,10 +182,6 @@ int CameraStream::process(const FrameBuffer &source,
ASSERT(type_ != Type::Direct);
- /*
- * \todo Buffer mapping and processing should be moved to a
- * separate thread.
- */
const StreamConfiguration &output = configuration();
dest.destBuffer = std::make_unique<CameraBuffer>(
*dest.camera3Buffer, output.pixelFormat, output.size,
@@ -194,11 +193,19 @@ int CameraStream::process(const FrameBuffer &source,
dest.srcBuffer = &source;
- postProcessor_->process(&dest);
+ worker_->queueRequest(&dest);
return 0;
}
+void CameraStream::flush()
+{
+ if (!postProcessor_)
+ return;
+
+ worker_->flush();
+}
+
FrameBuffer *CameraStream::getBuffer()
{
if (!allocator_)
@@ -226,3 +233,87 @@ void CameraStream::putBuffer(FrameBuffer *buffer)
buffers_.push_back(buffer);
}
+
+CameraStream::PostProcessorWorker::PostProcessorWorker(PostProcessor *postProcessor)
+ : postProcessor_(postProcessor)
+{
+}
+
+CameraStream::PostProcessorWorker::~PostProcessorWorker()
+{
+ {
+ libcamera::MutexLocker lock(mutex_);
+ state_ = State::Stopped;
+ }
+
+ cv_.notify_one();
+ wait();
+}
+
+void CameraStream::PostProcessorWorker::start()
+{
+ {
+ libcamera::MutexLocker lock(mutex_);
+ ASSERT(state_ != State::Running);
+ state_ = State::Running;
+ }
+
+ Thread::start();
+}
+
+void CameraStream::PostProcessorWorker::queueRequest(Camera3RequestDescriptor::StreamBuffer *dest)
+{
+ {
+ MutexLocker lock(mutex_);
+ ASSERT(state_ == State::Running);
+ requests_.push(dest);
+ }
+
+ cv_.notify_one();
+}
+
+void CameraStream::PostProcessorWorker::run()
+{
+ MutexLocker locker(mutex_);
+
+ while (1) {
+ cv_.wait(locker, [&] {
+ return state_ != State::Running || !requests_.empty();
+ });
+
+ if (state_ != State::Running)
+ break;
+
+ Camera3RequestDescriptor::StreamBuffer *streamBuffer = requests_.front();
+ requests_.pop();
+ locker.unlock();
+
+ postProcessor_->process(streamBuffer);
+
+ locker.lock();
+ }
+
+ if (state_ == State::Flushing) {
+ std::queue<Camera3RequestDescriptor::StreamBuffer *> requests =
+ std::move(requests_);
+ locker.unlock();
+
+ while (!requests.empty()) {
+ postProcessor_->processComplete.emit(
+ requests.front(), PostProcessor::Status::Error);
+ requests.pop();
+ }
+
+ locker.lock();
+ state_ = State::Stopped;
+ }
+}
+
+void CameraStream::PostProcessorWorker::flush()
+{
+ libcamera::MutexLocker lock(mutex_);
+ state_ = State::Flushing;
+ lock.unlock();
+
+ cv_.notify_one();
+}
diff --git a/src/android/camera_stream.h b/src/android/camera_stream.h
index e9c320b1..7c6e887c 100644
--- a/src/android/camera_stream.h
+++ b/src/android/camera_stream.h
@@ -7,12 +7,16 @@
#ifndef __ANDROID_CAMERA_STREAM_H__
#define __ANDROID_CAMERA_STREAM_H__
+#include <condition_variable>
#include <memory>
#include <mutex>
+#include <queue>
#include <vector>
#include <hardware/camera3.h>
+#include <libcamera/base/thread.h>
+
#include <libcamera/camera.h>
#include <libcamera/framebuffer.h>
#include <libcamera/framebuffer_allocator.h>
@@ -20,9 +24,9 @@
#include <libcamera/pixel_format.h>
#include "camera_request.h"
+#include "post_processor.h"
class CameraDevice;
-class PostProcessor;
class CameraStream
{
@@ -125,8 +129,38 @@ public:
Camera3RequestDescriptor::StreamBuffer &dest);
libcamera::FrameBuffer *getBuffer();
void putBuffer(libcamera::FrameBuffer *buffer);
+ void flush();
private:
+ class PostProcessorWorker : public libcamera::Thread
+ {
+ public:
+ enum class State {
+ Stopped,
+ Running,
+ Flushing,
+ };
+
+ PostProcessorWorker(PostProcessor *postProcessor);
+ ~PostProcessorWorker();
+
+ void start();
+ void queueRequest(Camera3RequestDescriptor::StreamBuffer *request);
+ void flush();
+
+ protected:
+ void run() override;
+
+ private:
+ PostProcessor *postProcessor_;
+
+ libcamera::Mutex mutex_;
+ std::condition_variable cv_;
+
+ std::queue<Camera3RequestDescriptor::StreamBuffer *> requests_;
+ State state_ = State::Stopped;
+ };
+
int waitFence(int fence);
CameraDevice *const cameraDevice_;
@@ -143,6 +177,8 @@ private:
*/
std::unique_ptr<std::mutex> mutex_;
std::unique_ptr<PostProcessor> postProcessor_;
+
+ std::unique_ptr<PostProcessorWorker> worker_;
};
#endif /* __ANDROID_CAMERA_STREAM__ */
--
2.31.1
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