TotalView Users Guide - CI Wiki

Stepping (Part I)
� Set breakpoints at lines you choose, and let your program execute to
that breakpoint. See “Setting Breakpoints and Barriers” on page 351.
� Set conditional breakpoints that cause a program to stop after it evaluates
a condition that you define, for example “stop when a value is less
than eight. See “Setting Eval Points” on page 367.
TotalView provides additional features for working with breakpoints, process
barrier breakpoints, and eval points. For more information, see Chapter
16, “Setting Action Points,” on page 349.
Stepping (Part I)
You can use TotalView stepping commands to:
� Execute one source line or machine instruction at a time; for example,
Process > Step in the GUI and dstep in the CLI.
CLI: dstep
� Run to a selected line, which acts like a temporary breakpoint; for example,
Process > Run To.
CLI: duntil
� Run until a function call returns; for example, Process > Out.
CLI: dout
In all cases, stepping commands operate on the Thread of Interest (TOI). In
the GUI, the TOI is the selected thread in the current Process Window. In
the CLI, the TOI is the thread that TotalView uses to determine the scope of
the stepping operation.
On all platforms except SPARC Solaris, TotalView uses smart single-stepping
to speed up stepping of one-line statements that contain loops and conditions,
such as Fortran 90 array assignment statements. Smart stepping
occurs when TotalView realizes that it doesn’t need to step through an
instruction. For example, assume that you have the following statements:
integer iarray (1000,1000,1000)
iarray = 0
These two statements define one billion scalar assignments. If your computer
steps every instruction, you will probably never get past this statement. Smart
stepping means that TotalView single-steps through the assignment statement
at a speed that is very close to your computer’s native speed.
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