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

[Hans de Goede]

Hi,

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>

Regards,

Hans

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...






> ---
> 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