T-trace: Tracing Applications

This tutorial demonstrates how you can insert tracepoints in Tizen native applications and then run the T-trace tool to view the results.

This feature is supported in mobile applications only.

Warm-up

Become familiar with the T-trace API basics by learning about:

• Initializing Tracing

  Initialize tracing for use.

• Inserting Tracepoints

  Create custom tracepoints in your application.

Initializing Tracing

To initialize tracing:

1. To use the functions and data types of the T-trace API, include the <trace.h> header file in your application:

   #include <trace.h>
   

2. Make sure you have the libttrace.so T-trace library. The T-trace library provides a tracing function to write traces to the system trace buffer.
3. Check that the following prerequisites are fulfilled:
   • linux-2.6.27 kernel
   • debugfs mounted on /sys/kernel/debug

Inserting Tracepoints

To insert tracepoints:

• Use synchronous tracing.

  If the trace event starts and ends in a same context within the same process, thread, and function, use the trace_begin() and trace_end() functions to track the event. Note that every trace_begin() function matches up with a trace_end() function that occurs after it.

  int 
  main(void) 
  {
     int integer = 12;
     trace_begin("event name: %d", integer);
  
     trace_end();
  
     return 0;
  }
  

• Use asynchronous tracing.

  If the trace event starts and ends in a different context, use the trace_async_begin() and trace_async_end() functions to track the event. Note that every trace_async_begin() function matches with a trace_async_end() function that has the same name and cookie. As the cookie provides an identifier among several events, it must have a unique integer value.

  void 
  function1() 
  {
     int cookies_f1 = 123;
  
     trace_async_begin(cookies, "event name");
  } 
  
  void 
  function2() 
  {
     int cookies_f2 = 123;
  
     trace_async_end(cookies_f2, "event name");
  
  }
  

• Track the trace counter.

  To track the change of an integer counter on your application, use the trace_update_counter() function:

  void 
  function2(int count) 
  {
     trace_update_counter(count, "event_name");
  }