[{"id":35739,"web_url":"https://patchwork.libcamera.org/comment/35739/","msgid":"<175741023797.2127323.13396933237866864867@neptunite.rasen.tech>","date":"2025-09-09T09:30:37","subject":"Re: [PATCH v16 09/12] libcamera: software_isp: Make input buffer\n\tcopying configurable","submitter":{"id":17,"url":"https://patchwork.libcamera.org/api/people/17/","name":"Paul Elder","email":"paul.elder@ideasonboard.com"},"content":"Hi Milan,\n\nThanks for the patch.\n\nQuoting Milan Zamazal (2025-07-29 16:31:57)\n> On some platforms, working directly on the input buffer is very slow due\n> to disabled caching. This is why we copy the input buffer into standard\n> (cached) memory. This is an unnecessary overhead on platforms with\n> cached buffers.\n> \n> Let's make input buffer copying configurable. The default is still\n> copying, as it's overhead is much lower than contingent operations on\n> non-cached memory. Ideally, we should improve this in future to set the\n> default to non-copying if we can be sure under observable circumstances\n> that we are working with cached buffers.\n> \n> Completes software ISP TODO #6.\n> \n> Signed-off-by: Milan Zamazal \n> ---\n> Documentation/runtime_configuration.rst | 2 ++\n> src/libcamera/software_isp/TODO | 11 -----------\n> src/libcamera/software_isp/debayer_cpu.cpp | 7 +++++--\n> src/libcamera/software_isp/debayer_cpu.h | 3 ++-\n> src/libcamera/software_isp/software_isp.cpp | 3 ++-\n> 5 files changed, 11 insertions(+), 15 deletions(-)\n> \n> diff --git a/Documentation/runtime_configuration.rst b/Documentation/runtime_configuration.rst\n> index 8fd80c311..57285cadb 100644\n> --- a/Documentation/runtime_configuration.rst\n> +++ b/Documentation/runtime_configuration.rst\n> @@ -52,6 +52,7 @@ file structure:\n> pipeline_handler:\n> ...\n> simple:\n> + copy_input_buffer: # true/false\n> supported_devices:\n> - driver: # driver name, e.g. `mxc-isi`\n> software_isp: # true/false\n> @@ -85,6 +86,7 @@ Configuration file example\n> min_unicam_buffers: 2\n> min_total_unicam_buffers: 2\n> simple:\n> + copy_input_buffer: false\n> supported_devices:\n> - driver: mxc-isi\n> software_isp: true\n> diff --git a/src/libcamera/software_isp/TODO b/src/libcamera/software_isp/TODO\n> index a50db668e..2c919f442 100644\n> --- a/src/libcamera/software_isp/TODO\n> +++ b/src/libcamera/software_isp/TODO\n> @@ -71,17 +71,6 @@ per-frame buffers like we do for hardware ISPs.\n> \n> ---\n> \n> -6. Input buffer copying configuration\n> -\n> -> DebayerCpu::DebayerCpu(std::unique_ptr stats)\n> -> : stats_(std::move(stats)), gammaCorrection_(1.0)\n> -> {\n> -> enableInputMemcpy_ = true;\n> -\n> -Set this appropriately and/or make it configurable.\n> -\n> ----\n> -\n> 7. Performance measurement configuration\n> \n> > void DebayerCpu::process(FrameBuffer *input, FrameBuffer *output, DebayerParams params)\n> diff --git a/src/libcamera/software_isp/debayer_cpu.cpp b/src/libcamera/software_isp/debayer_cpu.cpp\n> index 66f6038c1..704d4e487 100644\n> --- a/src/libcamera/software_isp/debayer_cpu.cpp\n> +++ b/src/libcamera/software_isp/debayer_cpu.cpp\n> @@ -24,6 +24,7 @@\n> #include \"libcamera/internal/bayer_format.h\"\n> #include \"libcamera/internal/dma_buf_allocator.h\"\n> #include \"libcamera/internal/framebuffer.h\"\n> +#include \"libcamera/internal/global_configuration.h\"\n> #include \"libcamera/internal/mapped_framebuffer.h\"\n> \n> namespace libcamera {\n> @@ -38,8 +39,9 @@ namespace libcamera {\n> /**\n> * \\brief Constructs a DebayerCpu object\n> * \\param[in] stats Pointer to the stats object to use\n> + * \\param[in] configuration The global configuration\n> */\n> -DebayerCpu::DebayerCpu(std::unique_ptr stats)\n> +DebayerCpu::DebayerCpu(std::unique_ptr stats, const GlobalConfiguration &configuration)\n> : stats_(std::move(stats))\n> {\n> /*\n> @@ -50,7 +52,8 @@ DebayerCpu::DebayerCpu(std::unique_ptr stats)\n> * always set it to true as the safer choice but this should be changed in\n> * future.\n> */\n> - enableInputMemcpy_ = true;\n> + enableInputMemcpy_ =\n> + configuration.option({ \"pipelines\", \"simple\", \"copy_input_buffer\" }).value_or(true);\n\nI like how clean this becomes!\n\n\nReviewed-by: Paul Elder \n\n> \n> /* Initialize color lookup tables */\n> for (unsigned int i = 0; i < DebayerParams::kRGBLookupSize; i++) {\n> diff --git a/src/libcamera/software_isp/debayer_cpu.h b/src/libcamera/software_isp/debayer_cpu.h\n> index 926195e98..2f35aa18b 100644\n> --- a/src/libcamera/software_isp/debayer_cpu.h\n> +++ b/src/libcamera/software_isp/debayer_cpu.h\n> @@ -18,6 +18,7 @@\n> #include \n> \n> #include \"libcamera/internal/bayer_format.h\"\n> +#include \"libcamera/internal/global_configuration.h\"\n> \n> #include \"debayer.h\"\n> #include \"swstats_cpu.h\"\n> @@ -27,7 +28,7 @@ namespace libcamera {\n> class DebayerCpu : public Debayer, public Object\n> {\n> public:\n> - DebayerCpu(std::unique_ptr stats);\n> + DebayerCpu(std::unique_ptr stats, const GlobalConfiguration &configuration);\n> ~DebayerCpu();\n> \n> int configure(const StreamConfiguration &inputCfg,\n> diff --git a/src/libcamera/software_isp/software_isp.cpp b/src/libcamera/software_isp/software_isp.cpp\n> index 28e2a360e..b7651b7d2 100644\n> --- a/src/libcamera/software_isp/software_isp.cpp\n> +++ b/src/libcamera/software_isp/software_isp.cpp\n> @@ -114,7 +114,8 @@ SoftwareIsp::SoftwareIsp(PipelineHandler *pipe, const CameraSensor *sensor,\n> }\n> stats->statsReady.connect(this, &SoftwareIsp::statsReady);\n> \n> - debayer_ = std::make_unique(std::move(stats));\n> + const GlobalConfiguration &configuration = pipe->cameraManager()->_d()->configuration();\n> + debayer_ = std::make_unique(std::move(stats), configuration);\n> debayer_->inputBufferReady.connect(this, &SoftwareIsp::inputReady);\n> debayer_->outputBufferReady.connect(this, &SoftwareIsp::outputReady);\n> \n> -- \n> 2.50.1\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 593EEBDB13\n\tfor ;\n\tTue, 9 Sep 2025 09:30:49 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 2FCCA6936B;\n\tTue, 9 Sep 2025 11:30:48 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id C145069339\n\tfor ;\n\tTue, 9 Sep 2025 11:30:44 +0200 (CEST)","from neptunite.rasen.tech (unknown\n\t[IPv6:2404:7a81:160:2100:6f3a:4f34:f1fa:8b3])\n\tby perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id F3450605;\n\tTue, 9 Sep 2025 11:29:30 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; 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