This feature is useful for obtaining asynchronous backtraces from a multitude of running jobs. It uses the bt option to yod along with the program bt.
To use this feature, one starts a job with the bt option:
% yod -sz 7 -bt hello
which, again, attaches a gdb to each compute node process. Then, the gdb's can be interrupted for a back trace by doing
% bt -j 104 -n 21 -n 22
for instance. The bt command has the syntax
bt -j job_id -n node_id_0 ... -n node_id_n
The job id and node ids for the job in question can be obtained from pingd's output. Note, the job id is also contained in yod's initial output.
There is also a graphical version of the bt command, which is called C-bt. It is a Perl/Tk wrapper for bt which makes the task of entering a node list less cumbersome.
C-bt is started w/o command line options. It has a built-in pingd facility, which displays only those jobs on the machine associated with the current user. From this display a job id can be determined and entered. If pingd is selected once the job id has been entered C-bt displays the nodes associtated with the job as a set of buttons which can be selected and unselected in various ways. Once node selection has been made, a back trace for all selected nodes can be obtained by choosing ``get bt'' from the operations menu.