HP Caliper Advisor Rule Writer Guide

The description section of the report precedes the advice section. The description section

is important because the given set of databases might contain several different

executables, different versions of the same executable, and performance data from the

same or different types of systems. The Advisor reports specifically which version, of

which executable, and measured on which system that the advice applies to. In general,

the Advisor selects the most recent version of each executable it finds in the database(s)

and only uses consistent performance data for each analyzed object.

There are three elements to a piece of advice:

• Index

The index value represents the approximate importance of a particular piece of

advice. The values typically range from 0.0 to 100.0. The index value does not

indicate the improvement that could be achieved if the improvement suggestion

is followed. It is a rough means of ordering the relevance of various unrelated

performance issues. You can use the Advisor --advice-cutoff command-line

option to specify what the minimum index value should be.

• Class

All advice is classified as to what area of application performance it applies to.

Every piece of advice belongs to an advice class, which is one of the following:

— General: advice that doesn’t fit into a single category or can’t easily be classified

— CPU: items pertaining to non-memory CPU cycles

— Memory: for memory-related performance issues

— IO: for any I/O advice

— System: advice relating to system calls, system resources, process management,

and so forth

You can use the Advisor --advice-classes command-line option to specify

which classes of advice should be included in the report.

• Analysis

This is where the performance advice is printed.

An example is shown below. The bold numbers are annotations to explain the

analysis—they are not part of the output you receive.

-------------------------------------------------------------------------------

Index Class Analysis

-------------------------------------------------------------------------------

23.9 cpu Function profile

[cpu_fprof_1]

The percentage of ITLB misses (16.6%) is higher than normal.

This may indicate a poor setting for the virtual memory

instruction page size.

Try adding "+pi 4M" to the application's link command.

Use the following Caliper command to get a source listing of

the 'hot spots' in these routines:

caliper report fprof

24 Running the HP Caliper Advisor