HP Caliper User Guide Release 5.5 (5900-2351, August 2012)

C Event Set Descriptions for CPU Metrics
This appendix contains descriptions for the output of each event set available when you use the
cpu measurement.
NOTE: The information provided in this appendix for each report description is the same
information you receive when you use the --info option to append help to the end of text reports,
or when you use this command:
$ caliper info -r event-set
For more information, see “cpu Measurement Report Description ” (p. 181).
brpath Event Set
The brpath event set provides information on the dynamic mix of branch types (IPREL, indirect,
and return), branch path distribution, branch density, and so forth.
If you use this event set, the default is to make the measurements irrespective of CPU operating
state (that is, user, system, or interrupt states). By default, the idle state is not included in the
measurement. You can use command-line options to limit the scope of the measurement. Specifically,
you can:
• Limit measurement to a specific privilege level: -m event_set[:all|user|kernel]
• Include idle: --exclude-idle False
• Exclude the interruption state: --measure-on-interrupts off
• Only measure the interruption state: --measure-on-interrupts only
Metrics Available from this Measurement
The following metrics are available from this event set. These descriptions do not take into account
any command-line options you might use.
The metrics are:
• Raw CPI
The raw CPI is computed using all instructions retired. This includes nops and predicated off
instructions. The relationship between effective and raw CPI values can be obtained from the
cpi measurement.
• Branch Per Inst
This is the ratio of the number of total instructions and total branches retired. The instructions
retired includes nops and predicated off instructions. The cpi measurement can be used in
conjunction with this measurement to estimate the ratio of the number of branches and effective
instructions. The Itanium 2's PMU branch semantics considers predicated off branches as
retired untaken branches. Thus, predicated off branches are included as part of the denominator
in this derived metric.
• Branch Distribution
This metric provides a distribution of branches among the three major branch categories:
IPREL, Indirect, and Return. The IPREL category is further subdivided into call and noncall
branch categories. The Indirect category includes indirect call and noncall indirect branches.
The Return category covers all forms of return branches.
◦ %IPREL Call Branch
This metric provides the percentage of IPREL call branches among all branches.
◦ %IPREL Non-Call Branch
This metric provides the percentage of IPREL non-call branches among all branches.
230 Event Set Descriptions for CPU Metrics