HP Caliper User's Guide

cycles Measurement Report Description
Available only on Integrity servers dual-core Itanium 2 and Itanium 9300 quad-core
processor systems.
With the cycles measurement, produced by the cycles measurement configuration
file, HP Caliper measures and reports a flat profile of the instruction pointers (IPs).
This measurement uses the IP-EAR of the dual-core Itanium 2 and Itanium 9300
quad-core processor systems.
The flat profile is produced by statistical sampling of the execution trace buffer (ETB)
configured to capture IPs of retired intructions. The cycles measurement samples
the ETB at a regular interval, for example, at every N CPU cycles. This provides a
statistical identification of where CPU events are occurring.
The report shows two levels of information:
• Exact counts of CPU metrics summed across the entire run of an application
• Sampled IPs that are associated with particular locations in the measured
application.
When compared with the fprof measurement, the cycles measurement provides
the following two additional pieces of information when invoked with the -r all
option:
• Cycles Per Bundle: The average number of cycles elapsed to retire the bundle. If
there are no stalls, it should take exactly one cycle to retire a bundle. If the Cycle
Per Bundle information is more than 1, this means that many additional cycles of
stall were seen on that bundle.
• Split issues: In general, when an instruction does not issue at the same time as the
instruction immediately before it, the instruction execution is said to have a split
issue. The split issue can occur when there are explicit stop bits in a bundle or
there are insufficient machine resources of the type required to execute the
instruction. In the cycles report, the Cycles Per Bundle information is prefixed
with an asterisk (*) if instructions from that bundle are split issued.
The report shows measured data by thread, load module, function, source statement,
and instruction bundle.
Command-line options allow you to control the amount of data reported, how the data
is sorted, and the number of statements and instructions reported for each sampled
program location.
Example Command Line for Text Report
$ caliper cycles -ra -o reports/sample.txt ./wordplay thequickbrownfox
Example Command Line for CSV Report
$ caliper cycles --csv csvout ./wordplay thequickbrownfox
244 Descriptions of Measurement Reports