1. The Instruments Application
The Instruments application lets you gather a variety of application performance metrics, such as memory and network use.
2. The Shark Application
The Shark application lets you view system-level events, such as system calls, thread-scheduling decisions, interrupts, and virtual memory faults.
Note:
When performance problems in your code are more related to the interaction between your code, iOS, and the hardware architecture of the device, you can use Shark to get information about those interactions and find performance bottlenecks.
