HP Caliper User's Guide

The preceding lines in the entry describe the callers of this function.
The lines following the primary line describe its subroutines (called children in the call
graph). The entries are sorted by time spent in the function and its subroutines.
Hot Call Paths Part of the Report
This section reports the most probable hottest call paths. A call path represents a subset
of the program's execution. The Hot Call Paths section reports the percentage of a
program's CPU time that is attributed to specific call paths. Since scgprof does not
store the whole call stack, it only tries to report the most probable hot paths in the
program. There could be some false positives and false negatives as well in the report.
You can use the --callpath-cutoff option to specify cutoff values that limit the
hot callpaths reported in this section. See “--callpath-cutoff ” (page 74)“ .
Function Indexes
The Function Indexes, which follows the Call Graph, is an alphabetical list of each
function in your program with its index value.
Diagnostic Messages
The Diagnostic Messages appear at the end of the report.
gprof Fallacy and Possibly Misleading Results
The HP Caliper sampled call graph report (with the scgprof measurement) and the
call graph report (with the cgprof measurement) both produce gprof-like reports.
Thus, both these reports might produce misleading results regarding the amount of
time spent under a function. The inaccuracy results because the HP Caliper sampled
call graph and call graph reports estimate the amount of time spent in a function from
the number of times the function is called, regardless of the time actually spent in the
function. This is sometimes referred to as the gprof fallacy.
For example, if function A and B each call function C 10 times, scgprof and cgprof
assign the total time spent in function C equally to both functions A and B. However,
calls from function A might take longer than those from function B. In this example,
function A would have a higher effect on performance than function B, which the call
graph data would not show.
Keep this limitation in mind when you analyze sampled call graph and call graph
report results.
170 Producing a Sampled Call Graph Profile Analysis