[PATCH v2] libcamera: software_isp: Replace malloc() with std::vector<>

[Laurent Pinchart]

Hi Hans,

On Mon, Aug 05, 2024 at 12:22:02PM +0200, Hans de Goede wrote:
> On 8/4/24 3:36 PM, Laurent Pinchart wrote:
> > libcamera is implemented in C++, use std::vector<> to manage the
> > dynamically allocated line buffers instead of malloc() and free(). This
> > simplifies the code and improves memory safety by ensuring no allocation
> > will be leaked.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> 
> I have given this a spin with IPU6 + the softISP and everything still works:
> 
> Tested-by: Hans de Goede <hdegoede at redhat.com>

Thank you.

> p.s.
> 
> I do see an *unrelated* performance regression where the softISP processing
> time for 1920x1080 goes up from 3 ms / frame to 6 ms / frame. 1 ms of that
> is caused by the new 32bpp RGB sparse output support which qcam prefers
> over the previous 24bpp packed support forcing 24 bpp packed output fmt
> resolves the 1 ms difference which is expected since 32 bpp sparse writes
> 33% more data. But that still leaves 2 ms unaccounted for.
> 
> I'll try to dig into where those 2 ms are coming from. With moderen CPU
> turboing behavior it is hard to tell really. Might even be a kernel issue...

Is that a regression introduced by this patch, or a regression between a
particular point in the past and the last master branch ?

> > ---
> > Changes since v1:
> > 
> > - Use std::vector instead of new[]() and delete[]()
> > ---
> >  src/libcamera/software_isp/debayer_cpu.cpp | 31 +++++++++-------------
> >  src/libcamera/software_isp/debayer_cpu.h   |  2 +-
> >  2 files changed, 13 insertions(+), 20 deletions(-)
> > 
> > diff --git a/src/libcamera/software_isp/debayer_cpu.cpp b/src/libcamera/software_isp/debayer_cpu.cpp
> > index f8d2677d657a..077f7f4bc45b 100644
> > --- a/src/libcamera/software_isp/debayer_cpu.cpp
> > +++ b/src/libcamera/software_isp/debayer_cpu.cpp
> > @@ -49,16 +49,9 @@ DebayerCpu::DebayerCpu(std::unique_ptr<SwStatsCpu> stats)
> >  	/* Initialize color lookup tables */
> >  	for (unsigned int i = 0; i < DebayerParams::kRGBLookupSize; i++)
> >  		red_[i] = green_[i] = blue_[i] = i;
> > -
> > -	for (unsigned int i = 0; i < kMaxLineBuffers; i++)
> > -		lineBuffers_[i] = nullptr;
> >  }
> >  
> > -DebayerCpu::~DebayerCpu()
> > -{
> > -	for (unsigned int i = 0; i < kMaxLineBuffers; i++)
> > -		free(lineBuffers_[i]);
> > -}
> > +DebayerCpu::~DebayerCpu() = default;
> >  
> >  #define DECLARE_SRC_POINTERS(pixel_t)                            \
> >  	const pixel_t *prev = (const pixel_t *)src[0] + xShift_; \
> > @@ -526,13 +519,10 @@ int DebayerCpu::configure(const StreamConfiguration &inputCfg,
> >  	lineBufferPadding_ = inputConfig_.patternSize.width * inputConfig_.bpp / 8;
> >  	lineBufferLength_ = window_.width * inputConfig_.bpp / 8 +
> >  			    2 * lineBufferPadding_;
> > -	for (unsigned int i = 0;
> > -	     i < (inputConfig_.patternSize.height + 1) && enableInputMemcpy_;
> > -	     i++) {
> > -		free(lineBuffers_[i]);
> > -		lineBuffers_[i] = (uint8_t *)malloc(lineBufferLength_);
> > -		if (!lineBuffers_[i])
> > -			return -ENOMEM;
> > +
> > +	if (enableInputMemcpy_) {
> > +		for (unsigned int i = 0; i <= inputConfig_.patternSize.height; i++)
> > +			lineBuffers_[i].resize(lineBufferLength_);
> >  	}
> >  
> >  	measuredFrames_ = 0;
> > @@ -587,9 +577,10 @@ void DebayerCpu::setupInputMemcpy(const uint8_t *linePointers[])
> >  		return;
> >  
> >  	for (unsigned int i = 0; i < patternHeight; i++) {
> > -		memcpy(lineBuffers_[i], linePointers[i + 1] - lineBufferPadding_,
> > +		memcpy(lineBuffers_[i].data(),
> > +		       linePointers[i + 1] - lineBufferPadding_,
> >  		       lineBufferLength_);
> > -		linePointers[i + 1] = lineBuffers_[i] + lineBufferPadding_;
> > +		linePointers[i + 1] = lineBuffers_[i].data() + lineBufferPadding_;
> >  	}
> >  
> >  	/* Point lineBufferIndex_ to first unused lineBuffer */
> > @@ -614,9 +605,11 @@ void DebayerCpu::memcpyNextLine(const uint8_t *linePointers[])
> >  	if (!enableInputMemcpy_)
> >  		return;
> >  
> > -	memcpy(lineBuffers_[lineBufferIndex_], linePointers[patternHeight] - lineBufferPadding_,
> > +	memcpy(lineBuffers_[lineBufferIndex_].data(),
> > +	       linePointers[patternHeight] - lineBufferPadding_,
> >  	       lineBufferLength_);
> > -	linePointers[patternHeight] = lineBuffers_[lineBufferIndex_] + lineBufferPadding_;
> > +	linePointers[patternHeight] = lineBuffers_[lineBufferIndex_].data()
> > +				    + lineBufferPadding_;
> >  
> >  	lineBufferIndex_ = (lineBufferIndex_ + 1) % (patternHeight + 1);
> >  }
> > diff --git a/src/libcamera/software_isp/debayer_cpu.h b/src/libcamera/software_isp/debayer_cpu.h
> > index 1dac64351f1d..8237a64be733 100644
> > --- a/src/libcamera/software_isp/debayer_cpu.h
> > +++ b/src/libcamera/software_isp/debayer_cpu.h
> > @@ -146,7 +146,7 @@ private:
> >  	DebayerInputConfig inputConfig_;
> >  	DebayerOutputConfig outputConfig_;
> >  	std::unique_ptr<SwStatsCpu> stats_;
> > -	uint8_t *lineBuffers_[kMaxLineBuffers];
> > +	std::vector<uint8_t> lineBuffers_[kMaxLineBuffers];
> >  	unsigned int lineBufferLength_;
> >  	unsigned int lineBufferPadding_;
> >  	unsigned int lineBufferIndex_;
> > 
> > base-commit: 19bbca3c0b376ba0183f5db53472c8c46cd402b5

-- 
Regards,

Laurent Pinchart