HP UX Caliper Software How fprof Metrics Are Obtained, Information in fprof Measurement Reports

In this table, “program object” refers to any of the following:

•Thread

•Load module

•Function

•Source statement

•Instruction bundle

Table 26 Information in fprof Measurement Reports

Column	Description
% Total IP Samples	Percent of the total IP samples attributable to a given program object.
Cumulat % of Total	Running sum of the percent of total IP samples accounted for by the given program object and
	those listed above it.
IP Samples	Total number of IP samples attributed to the given program object.
Kernel Thread	Kernel Thread ID suffixed with the the name of the routine that the thread will execute once it
Identification Number	is created.
Load Module	Shared library or the main executable.
Function	Routine from your application.
File	Source file associated with a function.
Line	The column contains one of these:
Slot	• A source-code line number for rows showing statements
Col,Offset
	• An instruction slot number for rows showing instructions not on a bundle boundary
	• A source-code column number followed by an offset from the beginning address of a function
	for rows showing instructions on a bundle boundary
	Column and line numbers are preceded by “~” when they are approximate due to optimization.
>Statement	The column contains either a source statement preceded by “>” or a disassembled instruction.
Instruction	Statements that are out of order due to optimization are preceded by “*>”.

How fprof Metrics Are Obtained

HP Caliper obtains fprof metrics using the performance monitoring unit (PMU).

Exact counts are obtained from the PMU's performance monitor configuration (PMC)/performance monitor data (PMD) register pairs. Sampled IPs are obtained from the operating system.

HP Caliper takes samples by using the overflow of one of the PMU's event counters as a sampling trigger. Samples are taken every Nth PMU event, where both N and the sampling event are defined in the fprof measurement configuration file in the HP Caliper home directory in the config subdirectory. You can override the value in the measurement configuration file by using the -soption.

The list of processor metrics you can use for the sampling event are available from the file itanium2_cpu_counters.txt, located in the HP Caliper home directory in the doc/text subdirectory.

The IP collected at each sampling point is the IP recorded by the kernel (in the process's save state) when the PMU overflow trap is taken. The kernel does not record a instruction slot number. Thus, the lowest granularity HP Caliper reports is instruction bundles.

The IP that HP Caliper records is the address of the next instruction that will execute when the kernel resumes execution of your application. It is not the address of the instruction that caused the event that resulted in the PMU overflow trap. This is because of the delays associated with incrementing the PMU counter, detecting the overflow, and triggering the trap. This means that the instruction

fprof Measurement Report Description 203