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{
    "id": 25898,
    "url": "https://patchwork.libcamera.org/api/patches/25898/?format=api",
    "web_url": "https://patchwork.libcamera.org/patch/25898/",
    "project": {
        "id": 1,
        "url": "https://patchwork.libcamera.org/api/projects/1/?format=api",
        "name": "libcamera",
        "link_name": "libcamera",
        "list_id": "libcamera_core",
        "list_email": "libcamera-devel@lists.libcamera.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": ""
    },
    "msgid": "<20260120170701.400944-1-barnabas.pocze@ideasonboard.com>",
    "date": "2026-01-20T17:07:01",
    "name": "[RFC,v1] libcamera: software_isp: debayer: Take `DebayerParams` by ref",
    "commit_ref": null,
    "pull_url": null,
    "state": "superseded",
    "archived": false,
    "hash": "279f011c0baea8326aca6670c6daadeceb036aae",
    "submitter": {
        "id": 216,
        "url": "https://patchwork.libcamera.org/api/people/216/?format=api",
        "name": "Barnabás Pőcze",
        "email": "barnabas.pocze@ideasonboard.com"
    },
    "delegate": null,
    "mbox": "https://patchwork.libcamera.org/patch/25898/mbox/",
    "series": [
        {
            "id": 5726,
            "url": "https://patchwork.libcamera.org/api/series/5726/?format=api",
            "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=5726",
            "date": "2026-01-20T17:07:01",
            "name": "[RFC,v1] libcamera: software_isp: debayer: Take `DebayerParams` by ref",
            "version": 1,
            "mbox": "https://patchwork.libcamera.org/series/5726/mbox/"
        }
    ],
    "comments": "https://patchwork.libcamera.org/api/patches/25898/comments/",
    "check": "pending",
    "checks": "https://patchwork.libcamera.org/api/patches/25898/checks/",
    "tags": {},
    "headers": {
        "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>",
        "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 CDE37C3220\n\tfor <parsemail@patchwork.libcamera.org>;\n\tTue, 20 Jan 2026 17:07:06 +0000 (UTC)",
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        ],
        "Authentication-Results": "lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"ucFe0gfV\"; dkim-atps=neutral",
        "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1768928793;\n\tbh=RqkbJEnCgL0GbNM4dRDPdtWkLQoRdsRsHXKgYHqni+g=;\n\th=From:To:Subject:Date:From;\n\tb=ucFe0gfVRRvhEhW92BR2xqPi4DjagdrDUYOq5AkGv5hseJBEnz3dNOE5DES0CMhdS\n\tJzF1c9tnheINK27VMBlV5n/PzQzPJEX0crOdAafs3ZKGRg/bLaKYV13JcfCHq+9+0Y\n\tBdgGObcPOxlaadBnpzxEjKb8a5x8uWpcTBU3dpcA=",
        "From": "=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= <barnabas.pocze@ideasonboard.com>",
        "To": "libcamera-devel@lists.libcamera.org",
        "Subject": "[RFC PATCH v1] libcamera: software_isp: debayer: Take\n\t`DebayerParams` by ref",
        "Date": "Tue, 20 Jan 2026 18:07:01 +0100",
        "Message-ID": "<20260120170701.400944-1-barnabas.pocze@ideasonboard.com>",
        "X-Mailer": "git-send-email 2.52.0",
        "MIME-Version": "1.0",
        "Content-Type": "text/plain; charset=UTF-8",
        "Content-Transfer-Encoding": "8bit",
        "X-BeenThere": "libcamera-devel@lists.libcamera.org",
        "X-Mailman-Version": "2.1.29",
        "Precedence": "list",
        "List-Id": "<libcamera-devel.lists.libcamera.org>",
        "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>",
        "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>",
        "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>",
        "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>",
        "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>",
        "Errors-To": "libcamera-devel-bounces@lists.libcamera.org",
        "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>"
    },
    "content": "When calling `Debayer::process()` from `SoftwareIsp::process()`, the\n`DebayerParams` object is copied multiple time:\n\n  (1) call of `BoundMethodMember<...>::activate()`\n      inside `Object::invokeMethod()`\n  (2) constructor of `BoundMethodArgs<...>`\n      inside `BoundMethodMember<...>::activate()`\n  (3) call of `BoundMethodMember<...>::invoke()`\n      inside `BoundMethodArgs::invokePack()`\n  (4) call of the actual pointer to member function\n      inside `BoundMethodMember::invoke()`\n\nGiven that the type has a size of 5696 bytes at the moment on x86-64,\nwhile the size is expected to shrink considerably and compilers might\navoid one or two of the above copies, this is still not ideal. By making\n`Debayer::process()` take the parameter object by const lvalue reference,\nonly the copy in the `BoundMethodArgs` constructor remains. So do that.\n\nSigned-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>\n---\n src/libcamera/software_isp/debayer.cpp     | 2 +-\n src/libcamera/software_isp/debayer.h       | 4 ++--\n src/libcamera/software_isp/debayer_cpu.cpp | 2 +-\n src/libcamera/software_isp/debayer_cpu.h   | 2 +-\n src/libcamera/software_isp/debayer_egl.cpp | 6 +++---\n src/libcamera/software_isp/debayer_egl.h   | 6 +++---\n 6 files changed, 11 insertions(+), 11 deletions(-)",
    "diff": "diff --git a/src/libcamera/software_isp/debayer.cpp b/src/libcamera/software_isp/debayer.cpp\nindex 65a1762dd..3e7702525 100644\n--- a/src/libcamera/software_isp/debayer.cpp\n+++ b/src/libcamera/software_isp/debayer.cpp\n@@ -401,7 +401,7 @@ Debayer::~Debayer()\n  * \\brief Select the bayer params to use for the next frame debayer\n  * \\param[in] params The parameters to be used in debayering\n  */\n-void Debayer::setParams(DebayerParams &params)\n+void Debayer::setParams(const DebayerParams &params)\n {\n \tgreen_ = params.green;\n \tgreenCcm_ = params.greenCcm;\ndiff --git a/src/libcamera/software_isp/debayer.h b/src/libcamera/software_isp/debayer.h\nindex cd2db9930..99e22ed85 100644\n--- a/src/libcamera/software_isp/debayer.h\n+++ b/src/libcamera/software_isp/debayer.h\n@@ -47,7 +47,7 @@ public:\n \tvirtual std::tuple<unsigned int, unsigned int>\n \tstrideAndFrameSize(const PixelFormat &outputFormat, const Size &size) = 0;\n \n-\tvirtual void process(uint32_t frame, FrameBuffer *input, FrameBuffer *output, DebayerParams params) = 0;\n+\tvirtual void process(uint32_t frame, FrameBuffer *input, FrameBuffer *output, const DebayerParams &params) = 0;\n \tvirtual int start() { return 0; }\n \tvirtual void stop() {}\n \n@@ -92,7 +92,7 @@ private:\n \tvirtual Size patternSize(PixelFormat inputFormat) = 0;\n \n protected:\n-\tvoid setParams(DebayerParams &params);\n+\tvoid setParams(const DebayerParams &params);\n \tvoid dmaSyncBegin(std::vector<DmaSyncer> &dmaSyncers, FrameBuffer *input, FrameBuffer *output);\n \tstatic bool isStandardBayerOrder(BayerFormat::Order order);\n };\ndiff --git a/src/libcamera/software_isp/debayer_cpu.cpp b/src/libcamera/software_isp/debayer_cpu.cpp\nindex 00738c56b..b52f4d5c7 100644\n--- a/src/libcamera/software_isp/debayer_cpu.cpp\n+++ b/src/libcamera/software_isp/debayer_cpu.cpp\n@@ -740,7 +740,7 @@ void DebayerCpu::process4(uint32_t frame, const uint8_t *src, uint8_t *dst)\n \t}\n }\n \n-void DebayerCpu::process(uint32_t frame, FrameBuffer *input, FrameBuffer *output, DebayerParams params)\n+void DebayerCpu::process(uint32_t frame, FrameBuffer *input, FrameBuffer *output, const DebayerParams &params)\n {\n \tbench_.startFrame();\n \ndiff --git a/src/libcamera/software_isp/debayer_cpu.h b/src/libcamera/software_isp/debayer_cpu.h\nindex 67df2b93a..27eff021d 100644\n--- a/src/libcamera/software_isp/debayer_cpu.h\n+++ b/src/libcamera/software_isp/debayer_cpu.h\n@@ -37,7 +37,7 @@ public:\n \tstd::vector<PixelFormat> formats(PixelFormat input);\n \tstd::tuple<unsigned int, unsigned int>\n \tstrideAndFrameSize(const PixelFormat &outputFormat, const Size &size);\n-\tvoid process(uint32_t frame, FrameBuffer *input, FrameBuffer *output, DebayerParams params);\n+\tvoid process(uint32_t frame, FrameBuffer *input, FrameBuffer *output, const DebayerParams &params);\n \tSizeRange sizes(PixelFormat inputFormat, const Size &inputSize);\n \tconst SharedFD &getStatsFD() { return stats_->getStatsFD(); }\n \ndiff --git a/src/libcamera/software_isp/debayer_egl.cpp b/src/libcamera/software_isp/debayer_egl.cpp\nindex 9693d7252..1ac162427 100644\n--- a/src/libcamera/software_isp/debayer_egl.cpp\n+++ b/src/libcamera/software_isp/debayer_egl.cpp\n@@ -386,7 +386,7 @@ DebayerEGL::strideAndFrameSize(const PixelFormat &outputFormat, const Size &size\n \treturn std::make_tuple(stride, stride * size.height);\n }\n \n-void DebayerEGL::setShaderVariableValues(DebayerParams &params)\n+void DebayerEGL::setShaderVariableValues(const DebayerParams &params)\n {\n \t/*\n \t * Raw Bayer 8-bit, and packed raw Bayer 10-bit/12-bit formats\n@@ -509,7 +509,7 @@ void DebayerEGL::setShaderVariableValues(DebayerParams &params)\n \treturn;\n }\n \n-int DebayerEGL::debayerGPU(MappedFrameBuffer &in, int out_fd, DebayerParams &params)\n+int DebayerEGL::debayerGPU(MappedFrameBuffer &in, int out_fd, const DebayerParams &params)\n {\n \t/* eGL context switch */\n \tegl_.makeCurrent();\n@@ -536,7 +536,7 @@ int DebayerEGL::debayerGPU(MappedFrameBuffer &in, int out_fd, DebayerParams &par\n \treturn 0;\n }\n \n-void DebayerEGL::process(uint32_t frame, FrameBuffer *input, FrameBuffer *output, DebayerParams params)\n+void DebayerEGL::process(uint32_t frame, FrameBuffer *input, FrameBuffer *output, const DebayerParams &params)\n {\n \tbench_.startFrame();\n \ndiff --git a/src/libcamera/software_isp/debayer_egl.h b/src/libcamera/software_isp/debayer_egl.h\nindex a5033bc63..790348249 100644\n--- a/src/libcamera/software_isp/debayer_egl.h\n+++ b/src/libcamera/software_isp/debayer_egl.h\n@@ -50,7 +50,7 @@ public:\n \tstd::vector<PixelFormat> formats(PixelFormat input);\n \tstd::tuple<unsigned int, unsigned int> strideAndFrameSize(const PixelFormat &outputFormat, const Size &size);\n \n-\tvoid process(uint32_t frame, FrameBuffer *input, FrameBuffer *output, DebayerParams params);\n+\tvoid process(uint32_t frame, FrameBuffer *input, FrameBuffer *output, const DebayerParams &params);\n \tint start();\n \tvoid stop();\n \n@@ -72,9 +72,9 @@ private:\n \t\t\t\t std::vector<std::string> shaderEnv);\n \tint linkShaderProgram(void);\n \tint getShaderVariableLocations();\n-\tvoid setShaderVariableValues(DebayerParams &params);\n+\tvoid setShaderVariableValues(const DebayerParams &params);\n \tvoid configureTexture(GLuint &texture);\n-\tint debayerGPU(MappedFrameBuffer &in, int out_fd, DebayerParams &params);\n+\tint debayerGPU(MappedFrameBuffer &in, int out_fd, const DebayerParams &params);\n \n \t/* Shader program identifiers */\n \tGLuint vertexShaderId_ = 0;\n",
    "prefixes": [
        "RFC",
        "v1"
    ]
}