Re: [PATCH v3 7/7] perf docs: Remove the Android cross building document

[Namhyung Kim <namhyung@kernel.org>]

On Sat, Jul 06, 2024 at 07:29:12PM +0100, Leo Yan wrote:
> The Android NDK (as time being the latest LTS version is r26d) changes
> toolchain to LLVM / Clang, so GCC compilers is not included in the NDK
> anymore. Therefore, the Android document contains obsolete info for
> building perf binary with NDK.

Do you know if the version prior to the change is still used?

> 
> Furthermore, the Clang included in the Android NDK is problematic for
> cross compilation Aarch64 target. The building reports multiple errors
> with the compiler aarch64-linux-android34-clang.
> 
> Thus, delete Documentation/android.txt to avoid confusion.

If so, maybe we can keep the document little more and add a note that
this works only for some old versions.

I'm also curious if it's still broken after your fixes.

Thanks,
Namhyung

> 
> Signed-off-by: Leo Yan <leo.yan@arm.com>
> ---
>  tools/perf/Documentation/android.txt | 78 ----------------------------
>  1 file changed, 78 deletions(-)
>  delete mode 100644 tools/perf/Documentation/android.txt
> 
> diff --git a/tools/perf/Documentation/android.txt b/tools/perf/Documentation/android.txt
> deleted file mode 100644
> index 24a59998fc91..000000000000
> --- a/tools/perf/Documentation/android.txt
> +++ /dev/null
> @@ -1,78 +0,0 @@
> -How to compile perf for Android
> -=========================================
> -
> -I. Set the Android NDK environment
> -------------------------------------------------
> -
> -(a). Use the Android NDK
> -------------------------------------------------
> -1. You need to download and install the Android Native Development Kit (NDK).
> -Set the NDK variable to point to the path where you installed the NDK:
> -  export NDK=/path/to/android-ndk
> -
> -2. Set cross-compiling environment variables for NDK toolchain and sysroot.
> -For arm:
> -  export NDK_TOOLCHAIN=${NDK}/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin/arm-linux-androideabi-
> -  export NDK_SYSROOT=${NDK}/platforms/android-24/arch-arm
> -For x86:
> -  export NDK_TOOLCHAIN=${NDK}/toolchains/x86-4.9/prebuilt/linux-x86_64/bin/i686-linux-android-
> -  export NDK_SYSROOT=${NDK}/platforms/android-24/arch-x86
> -
> -This method is only tested for Android NDK versions Revision 11b and later.
> -perf uses some bionic enhancements that are not included in prior NDK versions.
> -You can use method (b) described below instead.
> -
> -(b). Use the Android source tree
> ------------------------------------------------
> -1. Download the master branch of the Android source tree.
> -Set the environment for the target you want using:
> -  source build/envsetup.sh
> -  lunch
> -
> -2. Build your own NDK sysroot to contain latest bionic changes and set the
> -NDK sysroot environment variable.
> -  cd ${ANDROID_BUILD_TOP}/ndk
> -For arm:
> -  ./build/tools/build-ndk-sysroot.sh --abi=arm
> -  export NDK_SYSROOT=${ANDROID_BUILD_TOP}/ndk/build/platforms/android-3/arch-arm
> -For x86:
> -  ./build/tools/build-ndk-sysroot.sh --abi=x86
> -  export NDK_SYSROOT=${ANDROID_BUILD_TOP}/ndk/build/platforms/android-3/arch-x86
> -
> -3. Set the NDK toolchain environment variable.
> -For arm:
> -  export NDK_TOOLCHAIN=${ANDROID_TOOLCHAIN}/arm-linux-androideabi-
> -For x86:
> -  export NDK_TOOLCHAIN=${ANDROID_TOOLCHAIN}/i686-linux-android-
> -
> -II. Compile perf for Android
> -------------------------------------------------
> -You need to run make with the NDK toolchain and sysroot defined above:
> -For arm:
> -  make WERROR=0 ARCH=arm CROSS_COMPILE=${NDK_TOOLCHAIN} EXTRA_CFLAGS="-pie --sysroot=${NDK_SYSROOT}"
> -For x86:
> -  make WERROR=0 ARCH=x86 CROSS_COMPILE=${NDK_TOOLCHAIN} EXTRA_CFLAGS="-pie --sysroot=${NDK_SYSROOT}"
> -
> -III. Install perf
> ------------------------------------------------
> -You need to connect to your Android device/emulator using adb.
> -Install perf using:
> -  adb push perf /data/perf
> -
> -If you also want to use perf-archive you need busybox tools for Android.
> -For installing perf-archive, you first need to replace #!/bin/bash with #!/system/bin/sh:
> -  sed 's/#!\/bin\/bash/#!\/system\/bin\/sh/g' perf-archive >> /tmp/perf-archive
> -  chmod +x /tmp/perf-archive
> -  adb push /tmp/perf-archive /data/perf-archive
> -
> -IV. Environment settings for running perf
> -------------------------------------------------
> -Some perf features need environment variables to run properly.
> -You need to set these before running perf on the target:
> -  adb shell
> -  # PERF_PAGER=cat
> -
> -IV. Run perf
> -------------------------------------------------
> -Run perf on your device/emulator to which you previously connected using adb:
> -  # ./data/perf
> -- 
> 2.34.1
>