Parallel Programming with Intel® Parallel Studio XE

Chapter 11

Debugging Parallel Applications

What's in This Chapter?

Introducing the Intel Debugger and its workflow

Detecting data races

Observing the runtime behavior of a threaded program

This chapter shows how to use the parallel debugging features of the Intel Debugger on your parallel or threaded application. One of the biggest challenges in parallel programming is tracking down data races. In this chapter you use the debugger to detect data races as you debug.

Unlike the error-finding techniques presented in other chapters, with a debugger you can single-step into your code and examine your parallel applications to confirm that the program is running as you expect. You can, as it were, sit inside your program and observe what is happening around you.

Introduction to the Intel Debugger

You are probably reading this chapter because you are developing or debugging a parallel program. Compared to pure serial software, parallel programs introduce additional issues that can produce problems that are difficult to track down and debug. The most common error is a data race, where one thread tries to read data that is being written by another thread. Programmers solve data races by inserting synchronization primitives in the code so that only one thread at a time can access shared data. Adding these primitives may solve the data race issue, but could inadvertently introduce a deadlock, with both threads waiting for each other to release the shared resource.

In addition to the risk of ...