TotalView Users Guide - CI Wiki

Debugging PVM (Parallel Virtual Machine) and DPVM Applications
You cannot use CLI variables to start both PVM and DPVM.
Automatically Acquiring PVM/DPVM Processes
When you start TotalView as part of a PVM or DPVM debugging session, it
takes the following actions:
� TotalView makes sure that no other PVM or DPVM taskers are running. If
TotalView finds a tasker on a host that it is debugging, it displays the following
message and then exits:
Fatal error: A PVM tasker is already running
on host 'host'
� TotalView finds all the hosts in the PVM or DPVM configuration. Using the
pvm_spawn() call, TotalView starts a TotalView Server (tvdsvr) on each remote
host that has the same architecture type as the host TotalView is
running on. It tells you it has started a debugger server by displaying the
following message:
Spawning TotalView Debugger Server onto PVM
host 'host'
If you add a host with a compatible computer architecture to your PVM or
DPVM debugging session after you start TotalView, it automatically starts a
debugger server on that host.
After all debugger servers are running, TotalView intercepts every PVM or
DPVM task created with the pvm_spawn() call on hosts that are part of the
debugging session. If a PVM or DPVM task is created on a host with a different
computer architecture, TotalView ignores that task.
When TotalView receives a PVM or DPVM tasker event, the following actions
occur:
1 TotalView reads the symbol table of the spawned executable.
2 If a saved breakpoint file for the executable exists and you have enabled
automatic loading of breakpoints, TotalView loads breakpoints for the
process.
3 TotalView asks if you want to stop the process before it enters the main()
routine.
If you answer Yes, TotalView stops the process before it enters main() (that
is, before it executes any user code). This allows you to set breakpoints in
the spawned process before any user code executes. On most computers,
TotalView stops a process in the start() routine of the crt0.o module
if it is statically linked. If the process is dynamically linked, TotalView stops
it just after it finishes running the dynamic linker. Because the Process
Window displays assembler instructions, you need to use the View >
Lookup Function command to display the source code for main().
CLI: dlist function-name
For more information on this command, see “Finding the Source Code for
Functions” on page 225.
154 Chapter 7: Setting Up Parallel Debugging Sessions