TotalView Users Guide - CI Wiki

Figure 150: The Threads Tab
Updating Process Information
Manipulating Processes and Threads
Normally, TotalView only updates information when the thread being executed
stops executing. You can force TotalView to update a window by
using the Window > Update command. You need to use this command if
you want to see what a variable’s value is while your program is executing.
When you use this command, TotalView momentarily stops execution so that it can
obtain the information that it needs. It then restarts the thread.
Holding and Releasing Processes and Threads
Many times when you are running a multi-process or multi-threaded program,
you want to synchronize execution to the same place. You can do this manually
using a hold command, or automatically by setting a barrier point.
When a process or a thread is held, any command that it receives that tells
it to execute are ignored. For example, assume that you place a hold on a
process in a control group that contains three processes. After you select
Group > Go, two of the three processes resume executing. The held process
ignores the Go command.
At a later time, you will want to run what is being held. Do this using a
Release command. When you release a process or a thread, you are telling
it that it can run. But you still need to tell it to execute, which means that it
is waiting to receive an execution command, such as Go, Out, or Step.
Manually holding and releasing processes and threads is useful in the following
instances:
� When you need to run a subset of the processes and threads. You can
manually hold all but the ones you want to run.
� When a process or thread is held at a barrier point and you want to run it
without first running all the other processes or threads in the group to
that barrier. In this case, you release the process or the thread manually,
and then run it.
TotalView can also hold a process or thread if it stops at a barrier breakpoint.
You can manually release a process or thread being held at a barrier
breakpoint. See “Setting Barrier Points” on page 362 for more information on
manually holding and releasing barrier breakpoint.
When TotalView is holding a process, the Root and Process Windows display
a held indicator, which is the uppercase letter H. When TotalView is
holding a thread, it displays a lowercase h.
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