Optimizing Applications on Android NDK

My application for Android NDK uses a single Open Source library in C. When it work, this library is too much load on the processor. Questions:

1. How understand what components of the library take the most pressure?

2. Is there开发者_如何学C any method to optimize? LOCAL_ARM_MODE: = arm greatly improves the performance?

There some tricks that can optimize your Android native code without too much efforts:

• turn on level 3 compiler optimizations using -O3 switch
• turn off string aliasing -fno-strict-aliasing (or you can turn it on if you are following the C-aliasing rules)
• turn on floating-point instructions support -mfpu=vfp -mfloat-abi=softfp