HP Caliper User's Guide

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.
300 Event Set Descriptions for CPU Metrics