HP XC System 3.x Software - Manual (Page 69)

6 Using HPCPI on an HP XC Cluster
This chapter describes additional procedures for using HPCPI on an HP XC cluster. This chapter
addresses the following topics:
•
“Overview” (page 69)
• “Collecting Data on Multiple Nodes” (page 70)
• “Collecting Data on One Node” (page 73)
Overview
When using HPCPI on an HP XC cluster you can do the following:
• Collect performance data from some or all nodes in the job allocation.
• Collect performance data from one node in the job allocation.
To collect performance data from all nodes in the job allocation, the hpcpid daemon must run
on all nodes in the job allocation. In addition, you can consolidate the data into a single database
and synchronize the epochs.
If you collect performance data from only one node in the job allocation, the hpcpid daemon
only needs to run on this node. If you are using HPCPI labels, you must execute the hpcpictl
label
command only on the node on which hpcpid is running, and use label selectors to
associate the label with data from the application instead of the mpirun or other distribution
utility process, as described in
“Starting a Distribution Utility from hpcpictl label” (page 73) .
Using Labels with mpirun and Other Distribution Utilities
Many distribution utilities (utilities that start programs on multiple nodes, such as mpirun)
create a new session and process group for the processes it launches, including processes it
launches on the local system.
There are two ways to establish HPCPI labels with distribution utilities:
• Execute the hpcpictl label command from the distribution utility as follows:
% mpirun ... hpcpictl label myLabel... myApp
Use this method to collect performance data from all nodes in the job allocation. You must
start the hpcpid daemon on all nodes in the job allocation if it is not already running, and
in most cases you will synchronize the database and epoch. For more information, see
“Collecting Data on Multiple Nodes” (page 70) .
• Execute the distribution utility from the hpcpictl label command as follows:
% hpcpictl label myLabel... mpirun... myApp
Use this method to collect performance data from only one node in the job allocation. The
hpcpid
daemon needs to run only on the node where you are collecting data; it does not
have to run on the other nodes in the cluster. For more information, see “Collecting Data
on One Node” (page 73) .
Overview 69