Build guide for Windows

Build guide for Windows#

Requirements#

  • Windows Server 2025

Prepare build environment#

  1. Install MSYS2

    Download the latest installer from https://www.msys2.org/

  2. Install npcap

    Download the latest installer from https://npcap.com/#download

  3. Run MSYS2 UCRT64

    Note: All the following commands should be executed in UCRT64 environment.

  4. Install tools

    pacman -S git pactoys unzip

    pacboy -S dlfcn:p gcc:p gtest:p json-c:p libpcap:p meson:p mman-win32:p

  5. Install npcap SDK

    wget https://npcap.com/dist/npcap-sdk-1.16.zip

    unzip -d npcap-sdk-1.16 ./npcap-sdk-1.16.zip

    cp -r ./npcap-sdk-1.16/lib/x64/. "${MSYSTEM_PREFIX}/lib"

Build DPDK#

  1. Clone the MTL repository

    git clone https://github.com/OpenVisualCloud/Media-Transport-Library.git

    cd ./Media-Transport-Library

    MTL_PATH="$PWD"

  2. Clone the DPDK repository

    Note: The DPDK repository should be located directly in the MTL repository.

    versions.env in the MTL repository holds the DPDK version to use. Read the file to set DPDK_VER.

    . "$MTL_PATH"/versions.env

    git clone -b "v${DPDK_VER}" https://github.com/DPDK/dpdk.git

  3. Convert the patch symlinks to files

    Run this step for the DPDK versions 22.03 to 23.11. For every other version, go to the next step.

    Note: Some patch files in these versions point to a patch of an older DPDK version. Git can write such a file as a text file that holds the target path. It does this when the checkout has core.symlinks=false. A file system that cannot hold symlinks makes Git set this value at clone time. This is frequent on Windows. Some of these files are text in the repository itself. git am and git apply reject a text file.

    The command replaces each text file with the content of its target. A symlink can point to a second symlink. The longest chain in the repository is two hops. The command makes three passes, one more than the chain needs. It rewrites only a file whose first line starts with ../ and ends with .patch, so it is safe to run twice.

    for _ in 1 2 3; do
    for f in "$MTL_PATH"/patches/dpdk/"${DPDK_VER}"/*.patch \
             "$MTL_PATH"/patches/dpdk/"${DPDK_VER}"/windows/*.patch; do
        [ -f "$f" ] || continue
        target=$(head -n 1 "$f")
        case "$target" in ../*.patch) cp "$(dirname "$f")/$target" "$f" ;; esac
    done
done

for f in "$MTL_PATH"/patches/dpdk/"${DPDK_VER}"/*.patch \
         "$MTL_PATH"/patches/dpdk/"${DPDK_VER}"/windows/*.patch; do
    [ -f "$f" ] || continue
    case "$(head -n 1 "$f")" in ../*.patch) echo "not converted: $f" ;; esac
done

    The command then checks each file again. A line in the output means the conversion is not complete. Report such a file in a GitHub issue.

    Note: The three passes are enough only while every chain stays inside one directory depth. A chain such as 23.11/windows/A.patch -> ../../23.07/A.patch -> ../23.03/A.patch makes the second pass compute the path 23.11/windows/../23.03/A.patch. This path does not exist, so cp writes an error and the text file stays. Nothing in the repository enforces the depth rule.

    Do not commit the result. A commit of the converted tree replaces each symlink with a large file. With core.symlinks=false, Git keeps the symlink mode and writes the patch body as the link target. Such an entry is not valid. No tool in this repository and no CI job finds either result.

    To remove the changes, use this command. It restores from HEAD, not from the index, so it also works after git add. It reverts the whole version directory:

    git -C "$MTL_PATH" restore --source=HEAD --staged --worktree patches/dpdk/"${DPDK_VER}"

  4. Apply the MTL patches for DPDK

    cd "${MTL_PATH}/dpdk"

    git am "$MTL_PATH"/patches/dpdk/"${DPDK_VER}"/*.patch

    git apply "$MTL_PATH"/patches/dpdk/"${DPDK_VER}"/windows/*.patch

  5. Build DPDK

    meson setup -Dmax_lcores=256 build

    meson compile -C build

    Create a copy of the sched.h file

    Note: DPDK installation overwrites the sched.h file and cause MTL build problems

    cp "${MSYSTEM_PREFIX}/include/sched.h" "${MTL_PATH}/sched.h.bak"

    meson install -C build

    Restore the copy

    cp "${MTL_PATH}/sched.h.bak" "${MSYSTEM_PREFIX}/include/sched.h"

Build MTL#

  1. Run the build script

    cd "$MTL_PATH"

    ./build.sh debugonly
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