Setting Breakpoints and Stepping through a Program

Action Points (breakpoints)

An action point is TotalView’s much more powerful version of a breakpoint. Here are the four types:

Breakpoint - stops execution of the processes or threads that reach it.

Process Barrier Point - holds each process when it reaches the barrier point until all processes in the group have reached the barrier point. Primarily for MPI programs.

Evaluation Point - executes a code fragment when it is reached. Enables you to set “conditional breakpoints” and perform conditional execution.

Watchpoint - monitors a location in memory and either stops execution or evaluates an expression when the value stored in memory is modified.

Set action points in the Process Window with a single left-click on the line number. TotalView displays a sign.

 

Figure 8: Breakpoint Set At a Line

 

View all action points in the Process Window’s Action Points tab.

 

Figure 9: Action Points Tab

When your program halts on an action point, TotalView reports this status in various ways, including in the Root Window, the Process Window’s Source Pane, and through a yellow arrow (Figure 9) on the Action Points tab.

Once you have created an action point, you can save, reload, suppress, and redefine its characteristics in a number of ways. You can set action points on all functions within a class or on a virtual function, and finely control how action points work in multi-threaded multi process programs.

See More

How how action points work: “About Action Points” in the TotalView User Guide

On setting action points: “Setting Action Points” in the TotalView User Guide

On the CLI command dactions to display, save, and reload action points: dactions in the TotalView Reference Guide

On the role of barrier points in multi-threaded processes: “Using Barrier Points” in the TotalView User Guide