| 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 |