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

◦ %Indirect Branch
◦ This metric provides the percentage of Indirect branches among all branches.
◦ %Return Branch
This metric provides the percentage of Return branches among all branches.
• IPREL Path Statistics
This metric provides path distribution and mispredict rate for both paths of a non-call IPREL
branch. Unconditional IPREL branches are included, so there is a slight bias toward the taken
path. There is also an untaken bias that is an artifact of the Itanium 2's branch semantics
defined by the PMU. In the Itanium 2, predicated off branches are considered retired untaken
branches. Thus, the untaken category will be biased by predicated off branches. For most
commercial applications, the untaken path will dominate if PBO has been successfully applied.
◦ %Taken
Percentage of taken non-call IPREL branches.
◦ %Taken Mispredicted (%mpb)
Percentage of mispredicted taken non-call IPREL branches.
◦ %Untaken
Percentage of non-taken non-call IPREL branches.
◦ %Untaken Mispredicted (%mpb)
Percentage of mispredicted non-taken non-call IPREL branches.
brpred Event Set
The brpred event set provides information useful in assessing the effectiveness of branch prediction
for the three major classes of branches: IPREL, Indirect, and Return.
The Itanium 2's branch semantics considers predicated off branches as retired untaken branches.
So the branch statistics include the impact of predicated off branches that were predicated to be
a taken branch. For each branch class (IPREL, Indirect, and Return), the frequency weight, percentage
of correct, wrong path, and wrong target prediction outcomes is provided. The weight is the
fractional part of each prediction outcome for each branch category that applies to the overall
branch prediction statistics.
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.
brpred Event Set 231