HP Caliper User's Guide

is reported with a kernel thread ID suffixed with the the name of the routine that the
thread will execute once it is created.
Hot Call Paths Part of the Report
This section reports the hottest call paths. A call path represents a subset of the program's
execution. The Hot Call Paths section reports the percentage of program's real time
that is attributed to specific call paths. You can use the --callpath-cutoff option
to specify cutoff values that limit the hot call paths reported in this section. You can
also use the --sort-by option to specify the metric you want to be used for sorting
and cutoffs. See “--callpath-cutoff ” (page 74) and “--sort-by” (page 95).
You can designate one or more functions as being of no interest using the
--skip-functions option. If a call stack sample contains this function as a leaf
routine, it will be skipped while reporting the call stack profile. See “--skip-functions
” (page 95).
Call Graph Part of the Report
This section reports the call graph produced from the call stack samples. All the call
graph entries—one for each function—are reported. Each entry has one or more lines
and delimited by the line full of dashes.
In each entry, the primary line is the one that starts with an index number in square
brackets. The preceding lines in the entry describe the callers of this function. The lines
following the primary line describe the callees of this function.
The entries are sorted by the number of Sample Hits In or Under Function.
Function Indexes
The Function Indexes is an alphabetical list of each function in your program with its
index value.
Avoids gprof Fallacy
The cstack measurement does not exhibit the gprof fallacy condition that the
scgprof and cgprof measurements do. (See “gprof Fallacy and Possibly Misleading
Results” (page 170)'.) This is because the real time of the program that is attributable to
a function is directly proportional to the number of Sample Hits In or Under Function.
It does not depend on the number of times a function is called.
Limitations to Using cstack
• Due to a kernel limitation on HP-UX, call stack sampling on HP-UX 11.23 (v2)
exhibits heavy system call bias, resulting in inaccurate call stack profile reports.
For an accurate call stack profile, you need to run cstack on HP-UX 11.31 (v3)
• You cannot use the caliper diff command with this measurement.
Avoids gprof Fallacy 193