Using the Android Native Development Kit (NDK)
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Transcript of Using the Android Native Development Kit (NDK)
Using the Android* Native Development Kit
(NDK)
Xavier Hallade, Technical Marketing Engineer
@ph0b - ph0b.com
3
Agenda
• The Android* Native Development Kit (NDK)
• Developing an application that uses the NDK
• Supporting several CPU architectures
• Summary and Q&A
Break
• Debugging
• Optimizing
• Intel® Tools and Libraries
• Summary and Q&A
4
Agenda
• The Android* Native Development Kit (NDK)
• Developing an application that uses the NDK
• Supporting several CPU architectures
• Summary and Q&A
Break
• Debugging
• Optimizing
• Intel® Tools and Libraries
• Summary and Q&A
5
Android* Native Development Kit (NDK)
What is it?
Build scripts/toolkit to incorporate native code in Android* apps via the Java Native Interface (JNI)
Why use it?
Performance
e.g., complex algorithms, multimedia applications, games
Differentiation
app that takes advantage of direct CPU/HW access
e.g., using SSSE3 for optimization
Fluid and lag-free animations
Software code reuse
Why not use it?
Performance improvement isn’t alwaysguaranteed, in contrary to the added complexity
6
C/C++Code
Makefilendk-build
Mix with Java*
GDB debug
Java Framework
Java Application
SDK APIs
JNI
Native Libs
Android* Applications
NDK APIs
Bionic C Library
NDK Application Development
Using JNI
7
NDK Platform
Android* NDK Application
Dalvik* Application
Android app
Class
Java Source
Compile with
Javac
Java Native
Library Class
Java* Native
Library
Compile with
Javac
Create C header with
javah -jni
Header file C/C++ Source
Code
Compile and Link C
Code
Dynamic
Library
Application
Files
Makefile
Optional thanks to
JNI_Onload
8
Compatibility with Standard C/C++
Bionic C Library:
Lighter than standard GNU C Library
Not POSIX compliant
pthread support included, but limited
No System-V IPCs
Access to Android* system properties
Bionic is not binary-compatible with the standard C library
It means you generally need to (re)compile everything using the Android NDK toolchain
9
Android* C++ SupportBy default, libstdc++ is used. It lacks:
Standard C++ Library support (except some headers)
C++ exceptions support
RTTI support
Fortunately, you have other libs available with the NDK:
Runtime Exceptions RTTI STL
system No No No
gabi++ Yes Yes No
stlport Yes Yes Yes
gnustl Yes Yes Yes
Choose which library to compile
against in your Makefile
(Application.mk file):
APP_STL := gnustl_shared
Postfix the runtime with _static
or _shared
For using C++ features, you also need to enable these in your Makefile:LOCAL_CPP_FEATURES += exceptions rtti
10
Agenda
• The Android* Native Development Kit (NDK)
• Developing an application that uses the NDK
• Supporting several CPU architectures
• Summary and Q&A
Break
• Debugging
• Optimizing
• Intel® Tools and Libraries
• Summary and Q&A
11
PSI
TS
PIDs
Installing the Android* NDKNDK is a platform dependant archive:
It provides:
A build environment
Android* headers and libraries
Documentation and samples
(these are very useful)
You can integrate it with Eclipse ADT:
We’ll talk about Android studio integration later
12
Standard Android* Project Structure
Native Sources - JNI Folder 1. Create JNI folder for native sources
3. Create Android.mk Makefile
4. Build Native libraries using NDK-BUILD script.
2. Reuse or create native c/c++ sources
NDK-BUILD will automatically create ABI libs folders.
Manually Adding Native Code to an Android* Project
13
Adding NDK Support to your Eclipse Android*
Project
14
Android* NDK Samples
Sample App Type
hello-jni Call a native function written in C from Java*.
bitmap-plasma Access an Android* Bitmap object from C.
san-angeles EGL and OpenGL* ES code in C.
hello-gl2 EGL setup in Java and OpenGL ES code in C.
native-activityC only OpenGL sample
(no Java, uses the NativeActivity class).
native-plasmaC only OpenGL sample
(also uses the NativeActivity class).
…
15
Focus on Native Activity
Only native code in the project
android_main() entry point running in its own thread
Event loop to get input data and frame drawing messages
/**
* This is the main entry point of a native application that is using
* android_native_app_glue. It runs in its own thread, with its own
* event loop for receiving input events and doing other things.
*/
void android_main(struct android_app* state);
16
PSI
TS
PIDs
Integrating Native Functions with Java*
Declare native methods in your Android* application (Java*) using the ‘native’ keyword:
public native String stringFromJNI();
Provide a native shared library built with the NDK that contains the methods used by your application:
libMyLib.so
Your application must load the shared library (before use… during class load for example):
static {
System.loadLibrary("MyLib");
}
There is two ways to associate your native code to the Java methods: javah and JNI_OnLoad
17
Javah Method
“javah” helps automatically generate the appropriate JNI header stubs
based on the Java* source files from the compiled Java classes files:
Example:
> javah –d jni –classpath bin/classes \
com.example.hellojni.HelloJni
Generates com_example_hellojni_HelloJni.h file with this
definition:
JNIEXPORT jstring JNICALL
Java_com_example_hellojni_HelloJni_stringFromJNI(JNIEn
v *, jobject);
18
Javah Method
C function that will be automatically mapped:jstring
Java_com_example_hellojni_HelloJni_stringFromJNI(JNIEnv* env,
jobject thiz )
{
return (*env)->NewStringUTF(env, "Hello from JNI !");
}
...
{
...
tv.setText( stringFromJNI() );
...
}
public native String stringFromJNI();
static {
System.loadLibrary("hello-jni");
}
19
JNI_OnLoad Method – Why ?
Proven method
No more surprises after methods registration
Less error prone when refactoring
Add/remove native functions easily
No symbol table issue when mixing C/C++ code
Best spot to cache Java* class object references
20
JNI_OnLoad Method
In your library name your functions as you wish and declare the mapping with JVM methods:
jstring stringFromJNI(JNIEnv* env, jobject thiz)
{
return env->NewStringUTF("Hello from JNI !");
}
static JNINativeMethod exposedMethods[] = {
{"stringFromJNI","()Ljava/lang/String;",(void*)stringFromJNI},
}
()Ljava/lang/String; is the JNI signature of the Java* method, you can retrieve it using the javap utility:
> javap -s -classpath bin\classes -p com.example.hellojni.HelloJni
Compiled from "HelloJni.java“
…
public native java.lang.String stringFromJNI();
Signature: ()Ljava/lang/String;
…
21
JNI_OnLoad Method
JNI_OnLoad is the library entry point called during load.
Here it applies the mapping previously defined.
extern "C" jint JNI_OnLoad(JavaVM* vm, void* reserved)
{
JNIEnv* env;
if (vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6) !=
JNI_OK)
return JNI_ERR;
jclass clazz = env->FindClass("com/example/hellojni/HelloJni");
if(clazz==NULL)
return JNI_ERR;
env->RegisterNatives(clazz, exposedMethods,
sizeof(exposedMethods)/sizeof(JNINativeMethod));
env->DeleteLocalRef(clazz);
return JNI_VERSION_1_6;
}
22
Memory Handling of Java* Objects
Memory handling of Java* objects is done by the JVM:
You only deal with references to these objects
Each time you get a reference, you must not forget to delete it after use
local references are automatically deleted when the native call returns to
Java
References are local by default
Global references are only created by NewGlobalRef()
23
Creating a Java* String
Memory is handled by the JVM, jstring is always a reference. You can call DeleteLocalRef() on it once you finished with it.
By the way:
Main difference with compiling JNI code in C or in C++ is the nature of “env” as you can see it here
Remember that otherwise, the API is the same
C:
jstring string =
(*env)->NewStringUTF(env, "new Java String");
C++:
jstring string = env->NewStringUTF("new Java String");
24
Getting a C/C++ String from Java* String
const char *nativeString = (*env)-
>GetStringUTFChars(javaString, null);
…
(*env)->ReleaseStringUTFChars(env, javaString,
nativeString);
//more secure and efficient:
int tmpjstrlen = env->GetStringUTFLength(tmpjstr);
char* fname = new char[tmpjstrlen + 1];
env->GetStringUTFRegion(tmpjstr, 0, tmpjstrlen, fname);
fname[tmpjstrlen] = 0;
…
delete fname;
25
Handling Java* Exceptions
// call to java methods may throw Java exceptions
jthrowable ex = (*env)->ExceptionOccurred(env);
if (ex!=NULL) {
(*env)->ExceptionClear(env);
// deal with exception
}
(*env)->DeleteLocalRef(env, ex);
26
JNI Primitive Types
Java* Type Native Type Description
boolean jboolean unsigned 8 bits
byte jbyte signed 8 bits
char jchar unsigned 16 bits
short jshort signed 16 bits
int jint signed 32 bits
long jlong signed 64 bits
float jfloat 32 bits
double jdouble 64 bits
void void N/A
27
JNI Reference Types
jobject
jclass
jstring
jarray
jobjectArray
jbooleanArray
jbyteArray
jcharArray
jshortArray
jintArray
jlongArray
jfloatArray
jdoubleArray
jthrowable
Arrays elements are manipulated using Get<type>ArrayElements()
and Get/Set<type>ArrayRegion()
Don’t forget to call ReleaseXXX() for each GetXXX() call.
28
Calling Java* MethodsOn an object instance:jclass clazz = (*env)->GetObjectClass(env, obj);
jmethodID mid = (*env)->GetMethodID(env, clazz,
"methodName", "(…)…");
if (mid != NULL)
(*env)->Call<Type>Method(env, obj, mid, parameters…);
Static call:jclass clazz = (*env)->FindClass(env, "java/lang/String");
jmethodID mid = (*env)->GetStaticMethodID(env, clazz,
"methodName", "(…)…");
if (mid != NULL)
(*env)->CallStatic<Type>Method(env, clazz, mid,
parameters…);
• (…)…: method signature
• parameters: list of parameters expected by the Java* method• <Type>: Java method return type
29
Throwing Java* Exceptions
jclass clazz =
(*env->FindClass(env, "java/lang/Exception");
if (clazz!=NULL)
(*env)->ThrowNew(env, clazz, "Message");
The exception will be thrown only when the JNI call returns to Java*, it
will not break the current native code execution.
30
Agenda
• The Android* Native Development Kit (NDK)
• Developing an application that uses the NDK
• Supporting several CPU architectures
• Break
• Summary and Q&A
• Debugging
• Optimizing
• Intel® Tools and Libraries
• Summary and Q&A
31
NDK Applications support on Intel® Platforms
Most will run w/o any recompilation…
Android NDK provides an x86 toolchain since 2011
A simple recompile using the Android NDK yields the
best performance
If there is specific processor dependent code, porting
may be necessary
32
Include all ABIs by setting APP_ABI to all in jni/Application.mk:
APP_ABI=all
The NDK will generate optimized code for all target ABIs
You can also pass APP_ABI variable to ndk-build, and specify each ABI:
ndk-build APP_ABI=x86
Configuring NDK Target ABIs
Build ARM v7a libs
Build ARM v5 libs
Build x86 libs
Build mips libs
33
Fat Binaries
By default, an APK contains libraries for every supported ABIs.
Use lib/armeabi libraries
Use lib/armeabi-v7a
libraries
Use lib/x86
libraries
libs/armeabi-v7a
libs/x86
libs/armeabi
Android project
…
The application will be filtered during installation (after download)
34
Multiple APKs
Google Play* supports multiple APKs for the same application.
What compatible APK will be chosen for a device entirely depends on the android:VersionCode
If you have multiple APKs for multiple ABIs, best is to simply prefix your current version code with a digit representing the ABI:
2310 6310
You can have more options for multiple APKs, here is a convention that will work
if you’re using all of these:
x86ARMv7
35
Uploading Multiple APKs to the store
Switch to Advanced mode before
uploading the second APK.
The interface almost doesn’t change.
But if you upload a new apk in
simple mode, it will overwrite the
former one.
You can get the same screen than on
the right. even if the new package
will not overwrite the previous one.
36
Uploading Multiple APKs to the store
Don’t forget to use different version codes for your different APKs.
37
Memory AlignmentBy default
Easy fix
struct TestStruct {
int mVar1;
long long mVar2;
int mVar3;
};
struct TestStruct {
int mVar1;
long long mVar2 __attribute__ ((aligned(8)));
int mVar3;
};
38
SIMD InstructionsNEON* instruction set on ARM* platforms
MMX™, Intel® SSE, SSE2, SSE3, SSSE3 on Intel® Atom™ processor based platforms
http://intel.ly/10JjuY4 - NEONvsSSE.h : wrap NEON functions and intrinsics to
SSE3 – 100% covered
Optimization Notice
Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.
Notice revision #20110804
//******* definition sample *****************
int8x8_t vadd_s8(int8x8_t a, int8x8_t b); // VADD.I8 d0,d0,d0
#ifdef USE_MMX
#define vadd_s8 _mm_add_pi8 //MMX
#else
#define vadd_s8 _mm_add_epi8
#endif
//…
Intel® Streaming SIMD Extensions (Intel® SSE)Supplemental Streaming SIMD Extensions (SSSE)
39
Multiple Code Paths
Compiler macros
• Directly inside source code
• No runtime overhead
• Works with all build configurations
#ifdef __i386__
strlcat(buf, "__i386__", sizeof(buf));
#endif
#ifdef __arm__
strlcat(buf, "__arm__", sizeof(buf));
#endif
#ifdef _MIPS_ARCH
strlcat(buf, "_MIPS_ARCH", sizeof(buf));
#endif
40
Multiple Code Paths
Inside Makefiles
ifeq ($(TARGET_ARCH_ABI),x86)
…
else
…
endif
41
3rd party libraries x86 support
Game engines/libraries with x86 support:
• Havok Anarchy SDK: android x86 target available
• Unreal Engine 3: android x86 target available
• Marmalade: android x86 target available
• Cocos2Dx: set APP_ABI in Application.mk
• FMOD: x86 lib already included, set ABIs in Application.mk
• AppGameKit: x86 lib already included, set ABIs in Application.mk
• libgdx: x86 lib now available in latest releases
• …
No x86 support but works on consumer devices:
• Corona
• Unity
42
Agenda
• The Android* Native Development Kit (NDK)
• Developing an application that uses the NDK
• Supporting several CPU architectures
• Summary and Q&A
Break
• Debugging
• Optimizing
• Intel® Tools and Libraries
• Summary and Q&A
43
Debugging with logcatNDK provides log API in <android/log.h>:
Usually used through this sort of macro:
#define LOGI(...) ((void)__android_log_print(ANDROID_LOG_INFO,
"APPTAG", __VA_ARGS__))
Example:
LOGI("accelerometer: x=%f y=%f z=%f", x, y, z);
int __android_log_print(int prio, const char *tag,
const char *fmt, ...)
44
Debugging with logcat
To get more information on native code execution:
adb shell setprop debug.checkjni 1
(already enabled by default in the emulator)
And to get memory debug information (root only):
adb shell setprop libc.debug.malloc 1
-> leak detection
adb shell setprop libc.debug.malloc 10
-> overruns detection
adb shell start/stop -> reload environment
45
Debugging with GDB and EclipseNative support must be added to your project
Pass NDK_DEBUG=1 to the ndk-build command, from the project
properties:
NDK_DEBUG flag is supposed to be automatically set for a debug
build, but this is not currently the case.
46
Debugging with GDB and Eclipse*
When NDK_DEBUG=1 is specified, a “gdbserver” file is added to your
libraries
47
Debugging with GDB and Eclipse*
Debug your project as a native Android* application:
48
Debugging with GDB and Eclipse
From Eclipse “Debug” perspective, you can manipulate breakpoints and debug your project
Your application will run before the debugger is attached, hence breakpoints you set near application launch will be ignored
49
ValgrindThe Valgrind tool suite provides a number of debugging and profiling tools that help you make your
programs faster and more correct.
Memcheck : It can detect many memory-related errors that are common in C and C++ programs and
that can lead to crashes and unpredictable behavior.
Setting up Valgrind
Download latest version on Valgrind from http://valgrind.org/downloads/
./configure
Make
Sudo make install
Steps above should install valgrind.
Compile your program with -g to include debugging information so that Memcheck's error messages
include exact line numbers.
gcc myprog.c
valgrind --leak-check=yes myprog arg1 arg2 ; Memcheck is the default tool. The --leak-check option
turns on the detailed memory leak detector. You can also invoke the leak check like this
Valgrind ./a.out
Use “–o” to optimize the program while compiling. Any other option slows down Valgrind to a
significant extent.
50
Interpreting Valgrind error messages
Example of output message from Valgrind Memcheck
==19182== Invalid write of size 4
==19182== at 0x804838F: f (example.c:6) ==19182== by 0x80483AB: main (example.c:11)
19182 : Process ID
“Invalid write..” is the error message
6 and 11 are line numbers
Add “--gen-suppressions=yes ” to suppress errors arising out of pre compiled libs and other mem leak errors that you cannot make changes to.
Memcheck cannot detect every memory error your program has. For example, it can't detect out-of-range reads or writes to arrays that are allocated statically or on the stack. But it should detect many errors that could crash your program
Suggested reading : http://valgrind.org/docs/manual/manual.html
51
Valgrind on Android x86Installing Valgrind
Download this package: https://my.syncplicity.com/share/7cse0vnb43auckm/valgrind-x86-android-emulator
Unzip and enter root of the unzipped package.
Install valgrind on the emulator using these commands:
adb push Inst /
adb shell chmod 777 /data/local/Inst
adb shell chmod 755 /data/local/Inst/bin/*
adb shell chmod 755 /data/local/Inst/lib/valgrind/*
Setting up a program to be run with Valgrind
adb shell setprop wrap.com.example.hellojni "logwrapper /data/local/Inst/bin/valgrind“ #Replace package name with your package name
Next startups of your app will be wrapped by valgrind and you'll see the output inside logcat.
Please note
These binaries are compatible with Intel HAXM 4.0.3 x86 emulator, not the 4.3.
You can use any OS as host
To use valgrind on a real device, you need to recompile valgrind for it (you can read the .sh file inside the zip to get the right cmd and adapt it) and you need to be root on it.
52
Agenda
• The Android* Native Development Kit (NDK)
• Developing an application that uses the NDK
• Supporting several CPU architectures
• Summary and Q&A
Break
• Debugging
• Optimizing
• Intel® Tools and Libraries
• Summary and Q&A
53
VectorizationSIMD instructions up to SSSE3 available on current Intel® Atom™ processor based platforms, Intel® SSE4.2 on the Intel Silvermont Microarchitecture
On ARM*, you can get vectorization through the ARM NEON* instructions
Two classic ways to use these instructions:
Compiler auto-vectorization
Compiler intrinsics
Optimization Notice
Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.
Notice revision #20110804
SSSE3, SSE4.2Vector size: 128 bit
Data types:
• 8, 16, 32, 64 bit integer
• 32 and 64 bit float
VL: 2, 4, 8, 16
X2
Y2
X2◦Y2
X1
Y1
X1◦Y1
X4
Y4
X4◦Y4
X3
Y3
X3◦Y3
127 0
Intel® Streaming SIMD Extensions (Intel® SSE)
Supplemental Streaming SIMD Extensions (SSSE)
54
GCC Flags
ffast-math influence round-off of fp arithmetic and so breaks strict IEEE
compliance
The other optimizations are totally safe
Add -ftree-vectorizer-verbose to get a vectorization report
ifeq ($(TARGET_ARCH_ABI),x86)
LOCAL_CFLAGS += -O3 -ffast-math -mtune=atom -msse3 -mfpmath=sse
else
LOCAL_CFLAGS += ...
endif
LOCAL_CFLAGS += -O3 -ffast-math -mtune=slm -msse4.2 -mfpmath=sse
To optimize for Intel Silvermont Microarchitecture (available starting with NDK r9
gcc-4.8 toolchain):
Optimization Notice
Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.
Notice revision #20110804
55
Agenda
• The Android* Native Development Kit (NDK)
• Developing an application that uses the NDK
• Supporting several CPU architectures
• Summary and Q&A
Break
• Debugging
• Optimizing
• Intel® Tools and Libraries
• Summary and Q&A
56
Intel x86 Emulator
Accelerator
Intel x86 Atom
System Image
Faster Android* Emulation on Intel® Architecture
Based Host PCPre-built Intel® Atom™ Processor Images
Android* SDK manager has x86 emulation images built-in
To emulate an Intel Atom processor based Android phone, install the “Intel Atom x86 System Image” available in the Android SDK Manager
Much Faster Emulation
Intel® Hardware Accelerated Execution Manager (Intel® HAXM) for Mac and Windows uses Intel®
Virtualization Technology (Intel® VT) to accelerate Android emulator
Intel VT is already supported in Linux* by KVM
57
Intel® Threading Building Blocks (Intel® TBB)
Specify tasks instead of manipulating threads
Intel® Threading Building Blocks (Intel® TBB) maps your logical tasks onto threads with
full support for nested parallelism
Targets threading for scalable performance
Uses proven efficient parallel patterns
Uses work-stealing to support the load balance of unknown execution time for tasks
Open source and licensed versions available on:
Linux*, Windows*, Mac OS X* and… Android*
Open Source version available on:
http://threadingbuildingblocks.org/
Licensed version available on:
http://software.intel.com/en-us/intel-tbb
58
Components of TBB (version 4.2)
Synchronization primitivesatomic operations
mutexes : classic, recursive, spin, queuing
rw_mutexes : spin, queuing
Parallel algorithmsparallel_for
parallel_for_each
parallel_reduce
parallel_do
parallel_scan
parallel_pipeline & filters
parallel_sort
parallel_invoke
Concurrent containersconcurrent_hash_map
concurrent_queue
concurrent_bounded_queue
concurrent_priority_queue
concurrent_vector
concurrent_unordered_map
concurrent_unordered_set
Task scheduler
Memory allocatorstbb_allocator, cache_aligned_allocator, scalable_allocator
Thread Local Storagecombinable
enumerable_thread_specific
flattened2d
Ranges and
partitioners
Flow Graphsfunctional nodes
(source, continue, function)
buffering nodes
(buffer, queue, sequencer)
split/join nodes
other nodes
Tasks & Task groups
59
Intel® TBB – Integration
#for including tbb in your project:
include $(CLEAR_VARS)
LOCAL_MODULE := tbb
LOCAL_SRC_FILES := $(TBB_PATH)/lib/android/libtbb.so
LOCAL_EXPORT_C_INCLUDES := $(TBB_PATH)/include
include $(PREBUILT_SHARED_LIBRARY)
#for calling tbb from your lib:
LOCAL_CPP_FEATURES := rtti exceptions
LOCAL_SHARED_LIBRARIES += tbb
LOCAL_CFLAGS += -DTBB_USE_GCC_BUILTINS -std=c++11
Android.mk
APP_STL := gnustl_shared Application.mk
System.loadLibrary("gnustl_shared");
System.loadLibrary("tbb");
System.loadLibrary("YourLib");
Java
60
Intel® Threading Building Blocks (Intel® TBB) -
Example#include <tbb/parallel_reduce.h>
#include <tbb/blocked_range.h>
double getPi() {
const int num_steps = 10000000;
const double step = 1./num_steps;
double pi = tbb::parallel_reduce(
tbb::blocked_range<int>(0, num_steps), //Range
double(0), //Value
//function
[&](const tbb::blocked_range<int>& r, double current_sum ) ->
double {
for (size_t i=r.begin(); i!=r.end(); ++i) {
double x = (i+0.5)*step;
current_sum += 4.0/(1.0 + x*x);
}
return current_sum; // updated value of the accumulator
},
[]( double s1, double s2 ) { //Reduction
return s1+s2;
}
);
return pi*step;
}
Computes reduction
over a range
Defining a one-
dimensional range
Lambda function with
range and initial value as
parm
Calculating a part of Pi
within the range r
Defining a reduction
function
61
Intel® Graphics Performance Analyzer
(Intel® GPA): System Analyzer
Profiles performance and Power
Real-time charts of CPU, GPU and power
metrics
Conduct real-time experiments with
OpenGL-ES* (with state overrides) to help
narrow down problems
Triage system-level performance with
CPU, GPU and Power metrics
Available freely on intel.com/software/gpa
62
1. Install APK, and
connect to Host PC via
adb
2. Run Intel® GPA System Analyzer
on development machine3. View Profile
Intel® Graphics Performance Analyzer (Intel® GPA):
How to Use the System Analyzer
63
Intel® C++ Compiler for Android*
• Based on Intel® C/C++ Compiler XE 14.0 for Linux*
• Integrates into the Android* NDK as additional toolchain
• Supports Intel® Atom™ processor optimization
• 79.95$
Available on http://software.intel.com/c-compiler-android
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http://www.projectanarchy.com/
Project Anarchy*
• Complete mobile game engine that includes Havok Vision Engine, Physics, Animation Studio and AI
• Free to publish on Android (ARM and x86), iOS, and Tizen
• C++ development environment
• Efficient asset management system
• LUA scripting and debugging
• Extensible source code and full library of sample materials
• Remote debugging
• File serving for live asset updates
• Remote input
• Visual debugger
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Summary
Use the NDK for performance critical applications and code reuse
It is easy to target multiple architectures
Our tools can help you getting most out of it
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Where to Get More Info
Intel® Developer Zone (Intel® DZ)• Real developers sharing knowledge and offering
help• Dedicated communities and forums focused on
your interests• Worldwide reach• News and insights on cutting edge technology
Android Developer on Intel Website• Great content you won’t find anywhere else• Technical articles, tools, and guides• Native app porting tips & case studies• Info on x86 emulator and Intel® Hardware Accelerated
Execution Manager• Active forums and blogs written by Intel and
community experts
Getting Started
Technical Content
Android Blogs
Support Forums
www.intel.com/software/android
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Resources
http://developer.android.com/tools/sdk/ndk/index.html - NDK
http://docs.oracle.com/javase/6/docs/technotes/guides/jni/spec/intro.html - JNI documentation
http://software.intel.com/en-us/blogs/2012/12/12/from-arm-neon-to-intel-mmxsse-automatic-porting-
solution-tips-and-tricks - Automatic porting of NEON* instructions
http://software.intel.com/en-us/blogs/2012/11/28/intel-for-android-developers-learning-series - Android* learning series
http://software.intel.com/en-us/articles/android-application-development-and-optimization-on-the-intel-atom-platform - NDK Apps Development
http://software.intel.com/en-us/articles/creating-and-porting-ndk-based-android-apps-for-ia/ - NDK Apps porting
http://software.intel.com/en-us/articles/android-texture-compression - Textures Compression
http://software.intel.com/en-us/articles/how-to-debug-an-app-for-android-x86-and-the-tools-to-use/ - NDK Apps debugging
http://software.intel.com/en-us/articles/android-tutorial-writing-a-multithreaded-application-using-intel-threading-building-blocks - TBB Android* Tutorial
http://developer.android.com/training/ - Google Android* developer guide
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