TotalView Users Guide - CI Wiki

How Parallelism Affects Behavior
How Parallelism Affects Behavior
A parallel program consists of some number of processes, each involving
some number of threads. Processes fall into two categories, depending on
when they are created:
� Initial process
A preexisting process from the normal run-time environment (that is, created
outside TotalView) or one that was created as TotalView loaded the
program.
� Spawned process
A new process created by a process executing under CLI control.
TotalView assigns an integer value to each individual process and thread
under its control. This process/thread identifier can be the system identifier
associated with the process or thread. However, it can be an arbitrary value
created by the CLI. Process numbers are unique over the lifetime of a debugging
session; in contrast, thread numbers are only unique while the process
exists.
Process/thread notation lets you identify the component that a command
targets. For example, if your program has two processes, and each has two
threads, four threads exist:
Thread 1 of process 1
Thread 2 of process 1
Thread 1 of process 2
Thread 2 of process 2
You identify the four threads as follows:
1.1—Thread 1 of process 1
1.2—Thread 2 of process 1
2.1—Thread 1 of process 2
2.2—Thread 2 of process 2
Types of IDs
Multi-threaded, multi-process, and distributed programs contain a variety
of IDs. The following types are used in the CLI and the GUI:
System PID This is the process ID and is generally called the PID.
System TID This is the ID of the system kernel or user thread. On
some systems (for example, AIX), the TIDs have no obvious
meaning. On other systems, they start at 1 and
are incremented by 1 for each thread.
TotalView Users Guide: version 8.7 209