[libcamera-devel] [PATCH v2 3/3] ipa: raspberrypi: Rate-limit the controller algorithms
Naushir Patuck
naush at raspberrypi.com
Fri Apr 16 16:36:33 CEST 2021
Hi David,
Thank you for your feedback.
On Fri, 16 Apr 2021 at 14:44, David Plowman <david.plowman at raspberrypi.com>
wrote:
> Hi Naush
>
> Thanks for version 2 of this patch, and especially for re-basing on
> top of my still-pending patch!
>
> Weirdly this one, which I'd have expected to be the "3/3" has ended up
> as a reply to the cover note, so not sure what's going on there. But
> anyway...
>
I think that is gmail causing issues by bunching 0/3 and 3/3 into a
conversation
for some reason, even though the subjects are (slightly) different. Happens
on my view as well!
>
> On Fri, 16 Apr 2021 at 11:31, Naushir Patuck <naush at raspberrypi.com>
> wrote:
> >
> > The controller algorithms currently run on every frame provided to the
> > IPA by the pipeline handler. This may be undesirable for very fast fps
> > operating modes where it could significantly increase the computation
> > cycles (per unit time) without providing any significant changes to the
> > IQ parameters. The added latencies could also cause dropped frames.
> >
> > Pass the FrameBuffer timestamp to the IPA through the controls. This
> > timestamp will be used to rate-limit the controller algorithms to run
> > with a minimum inter-frame time given by a compile time constant,
> > currently set to 16.66ms.
>
> Is it worth a remark on how we don't rate-limit while dropping frames?
> I don't really mind, though.
>
> >
> > Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> > ---
> > src/ipa/raspberrypi/raspberrypi.cpp | 48 +++++++++++++++++--
> > .../pipeline/raspberrypi/raspberrypi.cpp | 5 ++
> > 2 files changed, 49 insertions(+), 4 deletions(-)
> >
> > diff --git a/src/ipa/raspberrypi/raspberrypi.cpp
> b/src/ipa/raspberrypi/raspberrypi.cpp
> > index f6d1ab16a290..e96b169ca612 100644
> > --- a/src/ipa/raspberrypi/raspberrypi.cpp
> > +++ b/src/ipa/raspberrypi/raspberrypi.cpp
> > @@ -61,6 +61,14 @@ constexpr unsigned int DefaultExposureTime = 20000;
> > constexpr double defaultMinFrameDuration = 1e6 / 30.0;
> > constexpr double defaultMaxFrameDuration = 1e6 / 0.01;
> >
> > +/*
> > + * Determine the minimum allowable inter-frame duration (in us) to run
> the
> > + * controller algorithms. If the pipeline handler provider frames at a
> rate
> > + * higher than this, we rate-limit the controller prepare() and
> process() calls
>
> Strictly speaking, I guess they're still Prepare() and Process()...
> (until such time as the lower-casing elves strike those files!)
>
> > + * to lower than or equal to this rate.
> > + */
> > +constexpr double controllerMinFrameDuration = 1e6 / 60.0;
> > +
> > LOG_DEFINE_CATEGORY(IPARPI)
> >
> > class IPARPi : public ipa::RPi::IPARPiInterface
> > @@ -68,7 +76,7 @@ class IPARPi : public ipa::RPi::IPARPiInterface
> > public:
> > IPARPi()
> > : controller_(), frameCount_(0), checkCount_(0),
> mistrustCount_(0),
> > - lsTable_(nullptr), firstStart_(true)
> > + lastRunTimestamp_(0), lsTable_(nullptr),
> firstStart_(true)
> > {
> > }
> >
> > @@ -146,6 +154,12 @@ private:
> > /* Number of frames that need to be dropped on startup. */
> > unsigned int dropFrameCount_;
> >
> > + /* Frame timestamp for the last run of the controller. */
> > + uint64_t lastRunTimestamp_;
> > +
> > + /* Do we run a Controller::process() for this frame? */
> > + bool processPending_;
> > +
> > /* LS table allocation passed in from the pipeline handler. */
> > FileDescriptor lsTableHandle_;
> > void *lsTable_;
> > @@ -262,6 +276,7 @@ void IPARPi::start(const ControlList &controls,
> ipa::RPi::StartConfig *startConf
> > startConfig->dropFrameCount = dropFrameCount_;
> >
> > firstStart_ = false;
> > + lastRunTimestamp_ = 0;
> > }
> >
> > void IPARPi::setMode(const CameraSensorInfo &sensorInfo)
> > @@ -406,7 +421,7 @@ void IPARPi::signalStatReady(uint32_t bufferId)
> > {
> > if (++checkCount_ != frameCount_) /* assert here? */
> > LOG(IPARPI, Error) << "WARNING: Prepare/Process
> mismatch!!!";
> > - if (frameCount_ > mistrustCount_)
> > + if (processPending_ && frameCount_ > mistrustCount_)
> > processStats(bufferId);
> >
> > reportMetadata();
> > @@ -894,10 +909,11 @@ void IPARPi::returnEmbeddedBuffer(unsigned int
> bufferId)
> >
> > void IPARPi::prepareISP(const ipa::RPi::ISPConfig &data)
> > {
> > + int64_t frameTimestamp =
> data.controls.get(controls::draft::SensorTimestamp);
> > + RPiController::Metadata lastMetadata;
> > Span<uint8_t> embeddedBuffer;
> >
> > - rpiMetadata_.Clear();
> > -
> > + lastMetadata = std::move(rpiMetadata_);
> > fillDeviceStatus(data.controls);
> >
> > if (data.embeddedBufferPresent) {
> > @@ -920,6 +936,30 @@ void IPARPi::prepareISP(const ipa::RPi::ISPConfig
> &data)
> > if (data.embeddedBufferPresent)
> > returnEmbeddedBuffer(data.embeddedBufferId);
> >
> > + if (lastRunTimestamp_ && frameCount_ > dropFrameCount_ &&
> > + frameTimestamp - lastRunTimestamp_ <
> controllerMinFrameDuration * 1e3) {
> > + /*
> > + * Ensure we update the controller metadata with the new
> frame's
> > + * exposure/gain values so that the correct values are
> returned
> > + * out in libcamera metadata later on. All other
> metadata values
> > + * must remain the same as the last frame.
> > + */
> > + DeviceStatus currentDeviceStatus;
> > +
> > + rpiMetadata_.Get<DeviceStatus>("device.status",
> currentDeviceStatus);
> > + rpiMetadata_ = std::move(lastMetadata);
> > + rpiMetadata_.Set("device.status", currentDeviceStatus);
> > + processPending_ = false;
> > + LOG(IPARPI, Debug) << "Rate-limiting the controller!
> inter-frame duration: "
> > + << frameTimestamp - lastRunTimestamp_
> > + << ", min duration "
> > + << controllerMinFrameDuration * 1e3;
> > + return;
> > + }
> > +
> > + lastRunTimestamp_ = frameTimestamp;
> > + processPending_ = true;
> > +
> > ControlList ctrls(ispCtrls_);
>
> Hmm, yes, I see there's an interesting manoeuvre going on with the
> metadata. I wonder if there's a way to rearrange this that involves a
> bit less shuffling, maybe:
>
> first delete these lines:
> + lastMetadata = std::move(rpiMetadata_);
> fillDeviceStatus(data.controls);
>
> next, in place of:
> + DeviceStatus currentDeviceStatus;
> +
> + rpiMetadata_.Get<DeviceStatus>("device.status",
> currentDeviceStatus);
> + rpiMetadata_ = std::move(lastMetadata);
> + rpiMetadata_.Set("device.status", currentDeviceStatus);
>
> do this:
> fillDeviceStatus(data.controls);
>
> and finally after the if-block for the "skip the algos" case put these
> back:
> rpiMetadata_.Clear();
> fillDeviceStatus(data.controls);
>
I did try this type of logic initially, but I don't think it would work.
We need to call rpiMetadata_.Clear() and fillDeviceStatus() before
helper_->Prepare() is called at the beginning of the function. I cannot
move the latter call further down as it needs to run before my skip algos
check and the returnEmbeddedBuffer() call. So I think the existing
manoeuvre
is needed without more refactoring.
Regards,
Naush
>
> I don't know if this ends up tidier or not, perhaps it's best if you
> decide what you prefer. But I'm fine either way, so:
>
> Reviewed-by: David Plowman <david.plowman at raspberrypi.com>
>
> Thanks!
> David
>
> >
> > controller_.Prepare(&rpiMetadata_);
> > diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > index 2a917455500f..9cf9c8c6cebd 100644
> > --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > @@ -1414,6 +1414,11 @@ void
> RPiCameraData::unicamBufferDequeue(FrameBuffer *buffer)
> > * DelayedControl and queue them along with the frame
> buffer.
> > */
> > ControlList ctrl =
> delayedCtrls_->get(buffer->metadata().sequence);
> > + /*
> > + * Add the frame timestamp to the ControlList for the
> IPA to use
> > + * as it does not receive the FrameBuffer object.
> > + */
> > + ctrl.set(controls::draft::SensorTimestamp,
> buffer->metadata().timestamp);
> > bayerQueue_.push({ buffer, std::move(ctrl) });
> > } else {
> > embeddedQueue_.push(buffer);
> > --
> > 2.25.1
> >
>
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