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

[Ian Rogers]

On Thu, Jul 11, 2024 at 9:58 PM Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>
> 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?

The git log last mentions NDK 12 from 2016 working. I suspect these
instructions haven't worked for a good long while.

Thanks,
Ian

> >
> > 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@xxxxxxx>
> > ---
> >  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
> >