HP Caliper User's Guide

• Make all of the performance runs on the same type of system. Performance data
from runs made on incompatible systems will be ignored.
• Save each HP Caliper performance run in a separate database. This makes it easier
later to mix-and-match databases for analysis.
• When you re-run the Advisor, be sure to list all of the available, current databases:
the initial ones and all additional ones. This gives the Advisor the most performance
data to work with.
• If the application program is rebuilt, then start over with new performance
measurements and new databases. The Advisor will ignore obsolete data, but
doing so can slow down processing.
• If a large amount of advice is not printed due to cutoff limits, try increasing the
limits to see other relevant advice. There may be some particularly useful advice
just below the cutoff.
• Codify some of your past application-specific performance analysis by writing
custom rules. This customization of the Advisor helps to catch future application
performance regressions.
• The ordering of rule files and databases on the command line makes no difference
to the results produced by the Advisor. The only exception is in the case where
the databases contain data from different, incompatible systems for the same
executable object.
• If you want to use multiple rule files, consider writing a “super” rule file that
merely ‘includes’ the real rule files. If you do this, only the super rule file needs
to be given on the command line. If that rule file is named default, then you
don't need to use the --rule-files option.
• You can add frequently used command-line options as variables to the
.caliperinit file to save typing. Just remember that .caliperinit variable
names have slightly different spelling: the command-line-equivalent hyphen (-)
is replaced with the underscore (_).
How the HP Caliper Advisor Works
Here is a simplified explanation of how the Advisor works to clarify how analysis
objects are selected and which performance data is used:
1. The command-line options and .caliperinit variable settings are processed
and verified. If there are any errors, they are reported and the run terminates.
If no databases are specified, all the databases in the databases directory are opened
and validated. If there are any errors, the errors are reported and the run terminates.
If there is no data to analyze, the Advisor prints a “how to get started” help message
and the run terminates.
2. All the specified databases are opened and validated. If there are any errors, they
are reported and the run terminates.
How the HP Caliper Advisor Works 111