[libcamera-devel,v4,06/11] test: fence: Add test for the Fence class

14966 diff mbox series

Add a test for the Fence class by testing a Fence failure case, and
by testing a successfully signalled fence capture cycle.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
---
 test/fence.cpp   | 340 +++++++++++++++++++++++++++++++++++++++++++++++
 test/meson.build |   1 +
 2 files changed, 341 insertions(+)
 create mode 100644 test/fence.cpp

Hi Jacopo,

Thank you for the patch.

On Wed, Dec 01, 2021 at 03:29:31PM +0100, Jacopo Mondi wrote:
> Add a test for the Fence class by testing a Fence failure case, and
> by testing a successfully signalled fence capture cycle.
> 
> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
> ---
>  test/fence.cpp   | 340 +++++++++++++++++++++++++++++++++++++++++++++++
>  test/meson.build |   1 +
>  2 files changed, 341 insertions(+)
>  create mode 100644 test/fence.cpp
> 
> diff --git a/test/fence.cpp b/test/fence.cpp
> new file mode 100644
> index 000000000000..ee1c8343e01c
> --- /dev/null
> +++ b/test/fence.cpp
> @@ -0,0 +1,340 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (C) 2021, Google Inc.
> + *
> + * fence.cpp - Fence test
> + */
> +
> +#include <iostream>
> +#include <memory>
> +#include <sys/eventfd.h>
> +#include <unistd.h>
> +
> +#include <libcamera/base/event_dispatcher.h>
> +#include <libcamera/base/thread.h>
> +#include <libcamera/base/timer.h>
> +#include <libcamera/base/unique_fd.h>
> +#include <libcamera/base/utils.h>
> +
> +#include <libcamera/fence.h>
> +#include <libcamera/framebuffer_allocator.h>
> +
> +#include "camera_test.h"
> +#include "test.h"
> +
> +using namespace std::chrono_literals;
> +using namespace libcamera;
> +using namespace std;
> +
> +class FenceTest : public CameraTest, public Test
> +{
> +public:
> +	FenceTest();
> +
> +protected:
> +	int init() override;
> +	int run() override;
> +	void cleanup() override;
> +
> +private:
> +	int validateExpiredRequest(Request *request);
> +	void requestComplete(Request *request);
> +	void signalFence();
> +
> +	std::unique_ptr<Fence> fence_;
> +	EventDispatcher *dispatcher_;
> +	UniqueFD eventFd_;
> +	Timer fenceTimer_;
> +
> +	std::vector<std::unique_ptr<Request>> requests_;
> +	std::unique_ptr<CameraConfiguration> config_;
> +	FrameBufferAllocator *allocator_;

With a unique_ptr you could avoid the cleanup() function (and also avoid
a leak in a failure path in init()).

> +
> +	Stream *stream_;
> +
> +	bool expectedCompletionResult_ = true;
> +	bool expectFenceFailure_ = true;
> +
> +	unsigned int completedRequest_;
> +
> +	unsigned int signalledRequestId_;
> +	unsigned int expiredRequestId_;
> +	unsigned int nbuffers_;
> +
> +	int efd2_;
> +	int efd_;
> +};
> +
> +FenceTest::FenceTest()
> +	: CameraTest("platform/vimc.0 Sensor B")
> +{
> +}
> +
> +int FenceTest::init()
> +{
> +	dispatcher_ = Thread::current()->eventDispatcher();
> +

I'd add a comment here to record a need for future development:

	/*
	 * Create an eventfd() to model the fence. This is enough to support the
	 * needs of libcamera which only needs to wait for read events through
	 * poll(). Once native support for fences will be available in the
	 * backend kernel APIs this will need to be replaced by a sw_sync fence,
	 * but that requires debugfs.
	 */

> +	eventFd_ = UniqueFD(eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK));
> +	if (!eventFd_.isValid()) {
> +		cerr << "Unable to create eventfd" << endl;
> +		return TestFail;
> +	}
> +
> +	/*
> +	 * Keep a copy of the original fd value to validate that an expired
> +	 * fence has the same fd value.
> +	 */
> +	efd_ = eventFd_.get();
> +
> +	config_ = camera_->generateConfiguration({ StreamRole::Viewfinder });
> +	if (!config_ || config_->size() != 1) {
> +		cerr << "Failed to generate default configuration" << endl;
> +		return TestFail;
> +	}
> +
> +	if (camera_->acquire()) {
> +		cerr << "Failed to acquire the camera" << endl;
> +		return TestFail;
> +	}
> +
> +	if (camera_->configure(config_.get())) {
> +		cerr << "Failed to set default configuration" << endl;
> +		return TestFail;
> +	}
> +
> +	StreamConfiguration &cfg = config_->at(0);
> +	stream_ = cfg.stream();
> +
> +	allocator_ = new FrameBufferAllocator(camera_);
> +	if (allocator_->allocate(stream_) < 0)
> +		return TestFail;
> +
> +	nbuffers_ = allocator_->buffers(stream_).size();
> +	if (nbuffers_ < 2) {
> +		cerr << "Not enough buffers available" << endl;
> +		return TestFail;
> +	}
> +
> +	signalledRequestId_ = nbuffers_ - 2;
> +	expiredRequestId_ = nbuffers_ - 1;
> +
> +	return TestPass;
> +}
> +
> +int FenceTest::validateExpiredRequest(Request *request)
> +{
> +	FrameBuffer *buffer = request->buffers().begin()->second;
> +
> +	std::unique_ptr<Fence> fence = buffer->releaseFence();
> +	if (!fence) {
> +		cerr << "The expired fence should be present" << endl;
> +		return TestFail;
> +	}
> +
> +	if (!fence->isValid()) {
> +		cerr << "The expired fence should be valid" << endl;
> +		return TestFail;
> +	}
> +
> +	UniqueFD fd = fence->release();
> +	if (fd.get() != efd_) {
> +		cerr << "The expired fence file descriptor should not change" << endl;
> +		return TestFail;
> +	}
> +
> +	expectFenceFailure_ = false;
> +
> +	return 0;
> +}
> +
> +/* Callback to signal a fence waiting on the eventfd file descriptor. */
> +void FenceTest::signalFence()
> +{
> +	uint64_t value = 1;
> +	write(efd2_, &value, sizeof(value));
> +	dispatcher_->processEvents();
> +}
> +
> +void FenceTest::requestComplete(Request *request)
> +{
> +	uint64_t cookie = request->cookie();
> +	completedRequest_ = cookie;
> +
> +	/* We expect the last request to fail, if it doesn't happen, test fails. */
> +	if (expectFenceFailure_ && cookie == expiredRequestId_ &&
> +	    request->status() != Request::RequestCancelled) {
> +		cerr << "The last request should have failed: " << cookie << endl;
> +
> +		expectedCompletionResult_ = false;
> +		dispatcher_->interrupt();
> +		return;
> +	}
> +
> +	/* All other requests but the last one should be completed. */
> +	if (expectFenceFailure_ && cookie < expiredRequestId_ &&
> +	    request->status() != Request::RequestComplete) {
> +		cerr << "All requests but last should complete: " << cookie << endl;
> +
> +		expectedCompletionResult_ = false;
> +		dispatcher_->interrupt();
> +		return;
> +	}
> +
> +	/*
> +	 * If the last request has failed already, all the ones queued after
> +	 * that shall complete.
> +	 */
> +	if (!expectFenceFailure_ &&
> +	    request->status() != Request::RequestComplete) {
> +		cerr << "Unexpected request failure: " << cookie << endl;
> +
> +		expectedCompletionResult_ = false;
> +		dispatcher_->interrupt();
> +		return;
> +	}
> +
> +	/*
> +	 * The last request has failed.
> +	 * Validate its fence status and do not re-queue it.
> +	 */
> +	if (cookie == expiredRequestId_) {
> +		int ret = validateExpiredRequest(request);
> +		if (ret)
> +			expectedCompletionResult_ = false;
> +
> +		dispatcher_->interrupt();
> +		return;
> +	}
> +
> +	const Request::BufferMap &buffers = request->buffers();
> +	const Stream *stream = buffers.begin()->first;
> +	FrameBuffer *buffer = buffers.begin()->second;
> +
> +	/* A succesfully completed request should have the Fence closed. */
> +	std::unique_ptr<Fence> bufferFence = buffer->releaseFence();
> +	if (bufferFence) {
> +		cerr << "Unexpected valid fence in completed request" << endl;
> +
> +		expectedCompletionResult_ = false;
> +		dispatcher_->interrupt();
> +		return;
> +	}
> +
> +	request->reuse();
> +
> +	if (cookie == signalledRequestId_) {
> +		/*
> +		 * The second time this request is about to be queued add
> +		 * a fence to it.
> +		 *
> +		 * The main loop should signal it by using a timer to write to
> +		 * the eventfd file descriptor before the fence expires.
> +		 */
> +		UniqueFD eventFd2(eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK));
> +		if (!eventFd2.isValid()) {
> +			cerr << "Unable to create eventfd" << endl;
> +			expectedCompletionResult_ = false;

Shouldn't the dispatcher be interrupted here too ? I'm tempted to wrap
all the validation code (up to request->reuse()) in a separate
validateRequest() function, with requestComplete() doing

	uint64_t cookie = request->cookie();

	if (validateRequest(request) != TestPass) {
		expectedCompletionResult_ = false;
		completedRequest_ = cookie;
		dispatcher_->interrupt();
		return;
	}

	request->reuse();

	...

	camera_->queueRequest(request);

	completedRequest_ = cookie;
	dispatcher_->interrupt();

This would also avoid setting completedRequest_ too early, which could
possibly race with the code in the main loop (not entirely sure about
that though).

> +			return;
> +		}
> +		efd2_ = eventFd2.get();
> +
> +		std::unique_ptr<Fence> fence =
> +			std::make_unique<Fence>(std::move(eventFd2));

It looks like this whole code block could be moved to a separate
function and reused at init() time (or even at run() time when creating
the requests).

> +		request->addBuffer(stream, buffer, std::move(fence));
> +	} else {
> +		/* All the other requests continue to operate without fences. */
> +		request->addBuffer(stream, buffer);
> +	}
> +
> +	camera_->queueRequest(request);
> +
> +	/*
> +	 * Interrupt the dispatcher to return control to the main loop and
> +	 * activate the fenceTimer
> +	 . */

That looks weird.

> +	dispatcher_->interrupt();
> +}
> +
> +int FenceTest::run()
> +{
> +	for (const auto &[i, buffer] : utils::enumerate(allocator_->buffers(stream_))) {
> +		std::unique_ptr<Request> request = camera_->createRequest(i);
> +		if (!request) {
> +			cerr << "Failed to create request" << endl;
> +			return TestFail;
> +		}
> +
> +		int ret;
> +		if (i == expiredRequestId_) {
> +			/* This request will have a fence, and it will expire. */
> +			fence_ = std::make_unique<Fence>(std::move(eventFd_));
> +			if (!fence_->isValid()) {
> +				cerr << "Fence should be valid" << endl;
> +				return TestFail;
> +			}
> +
> +			ret = request->addBuffer(stream_, buffer.get(), std::move(fence_));
> +		} else {
> +			/* All other requests will have no Fence. */
> +			ret = request->addBuffer(stream_, buffer.get());
> +		}
> +
> +		if (ret) {
> +			cerr << "Failed to associate buffer with request" << endl;
> +			return TestFail;
> +		}
> +
> +		requests_.push_back(std::move(request));
> +	}
> +
> +	camera_->requestCompleted.connect(this, &FenceTest::requestComplete);
> +
> +	if (camera_->start()) {
> +		cerr << "Failed to start camera" << endl;
> +		return TestFail;
> +	}
> +
> +	for (std::unique_ptr<Request> &request : requests_) {
> +		if (camera_->queueRequest(request.get())) {
> +			cerr << "Failed to queue request" << endl;
> +			return TestFail;
> +		}
> +	}
> +
> +	expectedCompletionResult_ = true;
> +
> +	/* This timer serves to signal fences associated with "signalledRequestId_" */
> +	Timer fenceTimer;
> +	fenceTimer.timeout.connect(this, &FenceTest::signalFence);
> +
> +	/* Loop for one second. */
> +	Timer timer;
> +	timer.start(1000);
> +	while (timer.isRunning() && expectedCompletionResult_) {
> +		if (completedRequest_ == signalledRequestId_)
> +			/*
> +			 * signalledRequestId_ has just completed and it has
> +			 * been re-queued with a fence. Start the timer to
> +			 * signal the fence in 10 msec.
> +			 */
> +			fenceTimer.start(10);
> +
> +		dispatcher_->processEvents();
> +	}
> +
> +	camera_->requestCompleted.disconnect();

Is this needed ?

> +
> +	if (camera_->stop()) {
> +		cerr << "Failed to stop camera" << endl;
> +		return TestFail;
> +	}
> +
> +	return expectedCompletionResult_ ? TestPass : TestFail;
> +}
> +
> +void FenceTest::cleanup()
> +{
> +	delete allocator_;
> +}
> +
> +TEST_REGISTER(FenceTest)
> diff --git a/test/meson.build b/test/meson.build
> index daaa3862cdd6..2c9487e203e2 100644
> --- a/test/meson.build
> +++ b/test/meson.build
> @@ -39,6 +39,7 @@ internal_tests = [
>      ['event',                           'event.cpp'],
>      ['event-dispatcher',                'event-dispatcher.cpp'],
>      ['event-thread',                    'event-thread.cpp'],
> +    ['fence',                           'fence.cpp'],
>      ['file',                            'file.cpp'],
>      ['flags',                           'flags.cpp'],
>      ['hotplug-cameras',                 'hotplug-cameras.cpp'],